Tagged: NASA Spaceflight Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 1:23 pm on April 25, 2019 Permalink | Reply
    Tags: "Dream Chaser progress ahead of CRS2 as SNC keeps crew version alive", NASA Spaceflight   

    From NASA Spaceflight: “Dream Chaser progress ahead of CRS2 as SNC keeps crew version alive” 

    NASA Spaceflight

    From NASA Spaceflight

    April 25, 2019
    Chris Bergin

    1
    Sierra Nevada Corporation’s Dream Chaser is quietly making progress towards her latest goal of carrying out resupply missions to the International Space Station (ISS), starting in 2021. The Cargo variant of the spaceplane – also sporting an updated “color” scheme – is now deep into construction ahead of flying on NASA’s Commercial Resupply Services 2 (CRS2) missions.

    The company also made a rare reference to the crew version of the vehicle, which continues to be an active program – if without any NASA missions – under a Space Act Agreement (SAA) with the agency.

    Dream Chaser will be flying at least six missions to the ISS in the 2020s, following NASA’s contract award to SNC – along with SpaceX and Orbital ATK for the CRS2 missions.

    The addition of Sierra Nevada Corporation (SNC) to the list of commercial cargo resupply companies will now see the Dream Chaser mini-Shuttle fly in a cargo configuration for Station resupply runs.

    While the CRS stalwarts of Cygnus and Dragon are regular visitors to the ISS, Program Manager Kirk Shireman cited the need for “dissimilar redundancy” in adding Dream Chaser to the mix – a key selling point previously used by SNC during Dream Chaser’s crew transportation aspirations.

    Dream Chaser was making solid progress on the Commercial Crew milestones. The only blot on her report card was a landing gear failure during a 2013 landing test at the Dryden Flight Research Facility in California.

    The test was designed to verify and validate Dream Chaser’s low-atmosphere aerodynamics, flight control surfaces, flight characteristics for approach, flare and landing, and landing systems.

    During this test, the space plane flew itself toward the ground and runway for a landing approximately one minute after release.

    However, as it approached the runway and landing gear deployment was commanded, the left landing gear failed to deploy fully, resulting in the vehicle skidding off runway 22L at Edwards. Notably, the landing gear was donated by a fighter jet and was not a specific part of the Dream Chaser hardware.

    2
    First landing attempt

    Post-test recovery of Dream Chaser showed that while the craft suffered minor damage, the crew compartment was intact and all of its systems were still operational. Unintentionally, the landing gear failure accidentally demonstrated Dream Chaser’s ability to safely protect its crew/cargo and survive a partial “landing gear failure scenario” at landing.

    However, it was likely one of the reasons Dream Chaser lost out on the final funding round that ultimately saw SpaceX’s Crew Dragon (Dragon 2) and Boeing’s Starliner (CST-100) win contracts for the missions that will return domestic launch capability for US astronauts for the first time since the retirement of the Space Shuttle fleet in 2011.

    3
    Crew Dragon and Starliner heading to the ISS-Render by Nathan Koga for NSF/L2

    The decision was controversial and led to a Commercial Crew Transportation Capability (CCtCap) contract award protest from SNC after missing out on a slice of the $6.8 billion pot – of which the lion’s share was allocated to Boeing.

    SNC’s protest statement pointed to the Source Selection document, citing serious questions and inconsistencies.

    “In its 51 year history, SNC has never filed a legal challenge to a government contract award. However, in the case of the CCtCap award, NASA’s own Source Selection Statement and debrief indicate that there are serious questions and inconsistencies in the source selection process. SNC, therefore, feels that there is no alternative but to institute a legal challenge.

    “SNC’s Dream Chaser proposal was the second lowest priced proposal in the CCtCap competition. SNC’s proposal also achieved mission suitability scores comparable to the other two proposals. In fact, out of a possible 1,000 total points, the highest ranked and lowest ranked offerors were separated by a minor amount of total points and other factors were equally comparable.”

    The protest was ultimately unsuccessful. Dream Chaser did repeat the test in 2017, this time nailing the landing and rollout at Edwards Air Force Base.

    NASASpaceFlight.com

    Forums
    L2 Sign Up
    SLS/Orion
    SpaceX
    Commercial
    ISS
    International

    Other

    Dream Chaser progress ahead of CRS2 as SNC keeps crew version alive
    written by Chris Bergin April 25, 2019

    Sierra Nevada Corporation’s Dream Chaser is quietly making progress towards her latest goal of carrying out resupply missions to the International Space Station (ISS), starting in 2021. The Cargo variant of the spaceplane – also sporting an updated “color” scheme – is now deep into construction ahead of flying on NASA’s Commercial Resupply Services 2 (CRS2) missions.

    The company also made a rare reference to the crew version of the vehicle, which continues to be an active program – if without any NASA missions – under a Space Act Agreement (SAA) with the agency.

    Dream Chaser will be flying at least six missions to the ISS in the 2020s, following NASA’s contract award to SNC – along with SpaceX and Orbital ATK for the CRS2 missions.

    The addition of Sierra Nevada Corporation (SNC) to the list of commercial cargo resupply companies will now see the Dream Chaser mini-Shuttle fly in a cargo configuration for Station resupply runs.
    See Also

    While the CRS stalwarts of Cygnus and Dragon are regular visitors to the ISS, Program Manager Kirk Shireman cited the need for “dissimilar redundancy” in adding Dream Chaser to the mix – a key selling point previously used by SNC during Dream Chaser’s crew transportation aspirations.

    Dream Chaser was making solid progress on the Commercial Crew milestones. The only blot on her report card was a landing gear failure during a 2013 landing test at the Dryden Flight Research Facility in California.

    The test was designed to verify and validate Dream Chaser’s low-atmosphere aerodynamics, flight control surfaces, flight characteristics for approach, flare and landing, and landing systems.

    During this test, the space plane flew itself toward the ground and runway for a landing approximately one minute after release.

    However, as it approached the runway and landing gear deployment was commanded, the left landing gear failed to deploy fully, resulting in the vehicle skidding off runway 22L at Edwards. Notably, the landing gear was donated by a fighter jet and was not a specific part of the Dream Chaser hardware.

    Dream Chaser during her first landing attempt – via SNC

    Post-test recovery of Dream Chaser showed that while the craft suffered minor damage, the crew compartment was intact and all of its systems were still operational. Unintentionally, the landing gear failure accidentally demonstrated Dream Chaser’s ability to safely protect its crew/cargo and survive a partial “landing gear failure scenario” at landing.

    However, it was likely one of the reasons Dream Chaser lost out on the final funding round that ultimately saw SpaceX’s Crew Dragon (Dragon 2) and Boeing’s Starliner (CST-100) win contracts for the missions that will return domestic launch capability for US astronauts for the first time since the retirement of the Space Shuttle fleet in 2011.

    Crew Dragon and Starliner heading to the ISS – Render by Nathan Koga for NSF/L2

    The decision was controversial and led to a Commercial Crew Transportation Capability (CCtCap) contract award protest from SNC after missing out on a slice of the $6.8 billion pot – of which the lion’s share was allocated to Boeing.

    SNC’s protest statement pointed to the Source Selection document, citing serious questions and inconsistencies.

    “In its 51 year history, SNC has never filed a legal challenge to a government contract award. However, in the case of the CCtCap award, NASA’s own Source Selection Statement and debrief indicate that there are serious questions and inconsistencies in the source selection process. SNC, therefore, feels that there is no alternative but to institute a legal challenge.

    “SNC’s Dream Chaser proposal was the second lowest priced proposal in the CCtCap competition. SNC’s proposal also achieved mission suitability scores comparable to the other two proposals. In fact, out of a possible 1,000 total points, the highest ranked and lowest ranked offerors were separated by a minor amount of total points and other factors were equally comparable.”

    The protest was ultimately unsuccessful. Dream Chaser did repeat the test in 2017, this time nailing the landing and rollout at Edwards Air Force Base.

    Dream Chaser would then go on to gain a NASA contract via its cargo variant and has been passing milestones ahead of its debut launch on an Atlas V, currently expected to take place in early 2021.

    When the vehicle takes flight, she will look slightly different from recent renderings, with SNC deciding to alter the Thermal Protection System (TPS) design by adding more white tiles to the skin of the craft.

    SNC noted that while the change was to aid the obvious requirements on the TPS during re-entry, it also adds more protection against MMOD (MicroMeteoroid and Orbital Debris) threats.

    From the paperwork standpoint, Dream Chaser recently passed NASA’s Integrated Review Milestone 5 (IR5), a key status check on SNC’s performance of a variety of ground and flight operations. Cargo loading operations have been part of the ground operations testing.

    “Our Dream Chaser team continues to successfully execute milestones as we move closer to getting this spacecraft into space,” said Fatih Ozmen, SNC’s owner and CEO at the time of passing IR5. “The orbital spacecraft is being built and this milestone demonstrates the vehicle keeps passing key reviews and is making great strides.”

    SNC then released rare photos of the vehicle in a video – specifically the pressure vessel – under construction at Lockheed Martin’s famous Skunk Works.

    The video showed the heritage, albeit with obvious changes, between the crew and cargo versions of the Dream Chaser – with the latter allowing for a much larger capacity of cargo upmass, which will be its main job during CRS2.

    Notably, Dream Chaser’s downmass will be brought directly from the ISS to a runway, such as the Kennedy Space Center’s Shuttle Landing Facility (SLF), allowing for faster processing of critical experiments. This is a key part of the “dissimilar redundancy” when compared to other vehicles.

    SNC confirmed work is still active on the human-rated vehicle, which is technically still under a NASA contract, albeit via what is understood to be an unfunded Space Act Agreement (SAA).

    “While we may not be showing it off publicly, we still continue to work on the crew design through an agreement with NASA,” noted SNC in a twitter response. “We actually meet with the Commercial Crew Program regularly and brief milestones to them through that agreement.”

    This note becomes more interesting when considering the issues during the development of the Crew Dragon – specifically the anomaly during the SuperDraco thruster testing several days ago – and Starliner is likely to see both vehicles being delayed from launching humans, potentially into 2020.

    4
    Crew Dragon, Starliner and Dream Chaser all at the ISS. Render by Nathan Koga for NSF/L2

    Depending on just how much work is taking place on the crew Dream Chaser, NASA could – in theory – providing funding to ramp up the work on the Dream Chaser crew vehicle and create a back-up option in case of further issues with the two primary Commercial Crew vehicles.

    Despite the issues with Crew Dragon and Starliner, NASA is far more likely to continue to purchase more Soyuz flights to ensure it can launch American astronauts to the ISS and to provide an uninterrupted US presence on the orbital outpost.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA Spaceflight , now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 12:40 pm on February 8, 2019 Permalink | Reply
    Tags: NASA Spaceflight, NG-10 Cygnus departs ISS after 3 month science supply mission, Northrop Grumman controllers will fire Cygnus’ engine to raise the craft’s orbital altitude above that of the Station’s. In this higher orbit Cygnus will deploy two CubeSats for NanoRacks: MySat   

    From NASA Spaceflight: “NG-10 Cygnus departs ISS after 3 month science, supply mission” 

    NASA Spaceflight

    From NASA Spaceflight

    2
    Three months after its arrival at the International Space Station, the NG-10 Cygnus, named S.S. John Young, has departed the Station with it 5,500 lb (2,494 kg) of trash and disposable equipment.

    For the NG-10 S.S. John Young, Station crew spent the last few weeks packing the spacecraft with supplies and trash no longer needed aboard the outpost before closing Cygnus’ forward hatch and the corresponding port aboard the Station.

    See Also

    NG-10 Mission LIVE Updates
    NGIS Section
    L2 Antares/Cygnus Special
    Click here to Join L2

    As part of departure operations, ISS Flight Engineers Anne McClain (NASA) and David Saint-Jacques (Canadian Space Agency), entered the Cupola workstation on the end of Tranquility (Node-3) and used Canadarm2, the Station’s robotic arm, to grapple Cygnus prior to ground controllers sending commands to unbolt the spacecraft from its berth on the Unity (Node-1) module.

    McClain and Saint-Jacque then maneuvered the S.S. John Young to its departure attitude and location 10 meters from the ISS.

    After a series of readiness checks from NASA Mission Control Houston (MCC-H) and Northrop Grumman Mission Control Dulles (MCC-D), a “go” to release the spacecraft was given.

    McClain and Saint-Jacques then sent commands to Canadarm2’s Latching End Effector (the arm’s hand) snares to release Cygnus; they then backed the arm away from the spacecraft before Cygnus pulsed its maneuvering thrusters to begin departure from the Station.

    Cygnus will fly a straight-line trajectory under the careful watch of MCC-H, MCC-D, as well as McClain and Saint-Jacques, heading directly away from the International Space Station.

    Once Cygnus passes outside the 200 meter Keep Out Sphere (KOS) surrounding the Station, MCC-H and the Station astronauts will pass complete control of the S.S. John Young to Northrop Grumman in Dulles.

    3
    Regions around the International Space Station. (Credit: NASA)

    As is customary with Cygnus missions, the craft’s departure from the Station does not signal the end of its flight, merely the completion of its primary objective and commencement of its secondary mission.

    After leaving ISS, Northrop Grumman controllers will fire Cygnus’ engine to raise the craft’s orbital altitude above that of the Station’s.

    In this higher orbit, Cygnus will deploy two CubeSats for NanoRacks: MySat-1 and CHEFSat.

    MySat-1 is the first NanoRacks payload launched for the United Arab Emirates and is a joint program from Yahsat, Khalifa University of Science and Technology and Northrop Grumman.

    MySat-1 is an educational satellite to help students learn how to build durable satellites with skills that can be upscaled to larger, scientific probes.

    Joining MySat-1 in the high orbit deployment is CHEFSat from NASA. According to NASA, CHEFSat (Cost-effective High E-Frequency Satellite) will test consumer communications technology for use in space by flying a consumer-grade radio frequency device with the goal of preparing a low cost and readily available technology for mission use.

    Once #CHEFSat & #MySat1 are deployed above #ISS altitude, #Cygnus will travel well below @Space_Station to deploy #KickSat2, a #CubeSat from @NASAAmes & @Stanford. #KickSat2 will release small #ChipSats, tiny spacecraft on circuit boards, which will burn up after a few days #NG10 pic.twitter.com/N2bwHmB5h7

    — NanoRacks (@NanoRacks) November 16, 2018

    After those two deployments, Cygnus will lower its orbit below that of the Station’s. From this lower altitude, a third CubeSat, known as KickSat2 – itself carrying 100 ChipSats – will be deployed.

    According to NanoRacks, each ChipSat (a NASA Ames and Stanford University partnership) includes a power, sensor, and communication system on a printed circuit board that measures 3.5 by 3.5 cm, with a thickness of a few millimeters and a mass of less than 3.5 ounces.

    Released below the Station’s orbital altitude, the ChipSats will burn up harmlessly in Earth’s atmosphere within a few days of their release from Cygnus.

    The CubeSat element of Cygnus’ mission is designed to foster commercial activity and growth within the space sector while also enabling low-cost testing of new technologies that may one day become staples of space exploration.

    Previous post-ISS Cygnus activities have included such demonstrations, most notably the SAFFIRE series of experiments that tested fire suppression technology and fire-resistant materials for NASA’s upcoming Orion spacecraft.

    After releasing its CubeSat passengers, Cygnus will maneuver for its deorbit burn, currently scheduled for Monday, 25 February 2019. As with all previous Cygnus missions, the re-entry will be a destructive one, with the S.S. John Young burning up harmlessly over the southern Pacific Ocean.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA Spaceflight , now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 12:28 pm on January 26, 2019 Permalink | Reply
    Tags: , , , , NASA Spaceflight, , Saturn and its rings and dust   

    From NASA Spaceflight: “Cassini still reveals Saturn’s secrets more than a year after its mission’s end” 

    NASA Spaceflight

    From NASA Spaceflight

    January 25, 2019
    Chris Gebhardt

    1

    Cassini’s flagship mission to the ringed planet Saturn ended over a year ago, but data from the craft’s Grand Finale tour of the Saturnian system continues to allow scientists to unlock the mysteries surrounding the sixth planet in our solar system.

    Among the discoveries after the end of Cassini’s mission include a firm understanding of the planet’s rotational period, the the age of the planet’s iconic rings, observations of dust storms on its moon Titan, and numerous other scientific revelations.

    Grand Finale science returns:

    Cassini’s remarkable tenure at Saturn came to an end on 15 September 2017 after numerous mission extensions and scientific returns that scientists could only have dreamed of before the craft’s launch nearly 20 years prior on 15 October 1997.

    In an effort to execute planetary protection to ensure Cassini did not accidentally contaminate one of the potentially life harboring moons of Saturn, the craft was plunged into the ringed planet’s atmosphere for a destructive entry after a final set of 22 close orbits of the planet that constituted the mission’s Grand Finale.

    Knowing this was the end, Cassini scientists did something with their craft that no spacecraft had done before; they flew Cassini through the rings of Saturn and into Saturn’s upper atmosphere multiple times.

    The daring nature of the Grand Finale paid off handsomely, with a host of returns not possible during the craft’s more stable orbits of the planet in the years prior.

    In all, the Grand Finale revealed complex organic compounds embedded in water nanograins (very fine, small particles) raining down from Saturn’s rings into the planet’s upper atmosphere, observed how the rings interact with the planet and how inner-ring particles and gases fall directly into Saturn’s atmosphere, and revealed what the material looks like in the gap between the rings and a planet’s atmosphere.

    In terms of the organic compounds observed in water nanograins, scientists saw methane, ammonia, carbon monoxide, nitrogen, and carbon dioxide – organic compositions far different from the organic compounds found emanating from the icy moon Enceladus and on the methane-rich moon Titan.

    This result revealed the presence of at least three distinct groupings of organic molecules in the Saturnian system – something not expected.

    Additionally, Cassini observed ring particles and gases from the innermost ring raining down into the planet’s atmosphere. Inner-ring particles can take on electric charges and spiral along Saturn’s magnetic field lines, eventually falling into Saturn’s atmosphere at high latitudes in a phenomenon known as “ring rain.”

    But Grand Finale data revealed that some inner-ring particles fall from the rings and are dragged quickly into Saturn’s atmosphere at its equatorial latitudes at an impressive rate of 22,000 pounds (10,000 kg) of material per second.

    Moreover, the area between Saturn and its rings revealed even more surprises for scientists when Cassini was finally able sample the material in the ring gap. This sampling showed nanometer size particles, like smoke, residing in the region, suggesting an as-yet-unknown process grinding up ring particles into a smoke-like consistancy.

    2
    A few of the findings from Cassini’s direct sampling of the rings and atmosphere during the Grand Finale. NASA/JPL Caltech

    Additional data from the Grand Finale also revealed that Saturn and its rings are more interconnected than scientists thought, with Cassini showing previously unknown electric currents from the rings to the top of Saturn’s atmosphere.

    For NASA, Cassini’s daring and risky Grand Finale has been more than justified with the host of data returned, with Cassini Project Science Linda Spilker saying, “Almost everything going on in that region turned out to be a surprise. That was the importance of going there, to explore a place we’d never been before. And the expedition really paid off – the data is tremendously exciting.

    “Many mysteries remain as we put together pieces of the puzzle. Results from Cassini’s final orbits turned out to be more interesting than we could have imagined.”

    When in doubt, look to the rings:

    For decades, a persistent mystery has puzzled scientists about Saturn: how long is a day on the ringed planet?

    It might seem like an easy question to answer, after all, one needs only observe the rotational rate of the planet. But therein lies the problem. Saturn has no solid surface and no defined feature in its gaseous atmosphere to track as the planet rotates.

    Moreover, the planet’s unusual magnetic field masks the planet’s rotation rate.

    But as it turned out, the answer to Saturn’s rotation rate, and therefore the length of its day, resided in the planet’s iconic rings.

    3
    Dive between Saturn and innermost rings. NASA/JPL Caltech

    During the Grand Finale, Cassini flew through Saturn’s rings multiple times, observing the icy and rocky components in unprecedented detail – observations that allowed scientists studying wave patterns in the rings to find that the rings respond to vibrations within Saturn’s interior.

    According to Christopher Mankovich, a graduate student in astronomy and astrophysics at the University of California, Santa Cruz, the vibrations within the rings acted as seismometers measuring vibrations in Saturn’s interior.

    “Particles throughout the rings can’t help but feel these oscillations in the gravity field. At specific locations in the rings, these oscillations catch ring particles at just the right time in their orbits to gradually build up energy, and that energy gets carried away as an observable wave.”

    Tracking these observable waves led Mankovich to develop models of Saturn’s internal structure that’s allowed him to track the movements of the interior and thus calculate Saturn’s rotation rate.

    Using this data, Mankovich was able to determine that Saturn’s rotation rate is 10 hours 33 minutes 38 seconds.

    But Saturn’s rings themselves also held a tantalizing surprise for scientists that was not revealed until the Grand Finale dives through this icy and rocky region.

    ____________________________________

    Saturn’s rings are its most famous feature and make Saturn the most recognizable and exotic planet in the solar system. But new information from Cassini’s Grand Finale shows that the rings formed just 10 to 100 million years ago, meaning the planet’s most iconic feature is also one of its youngest.

    Understanding the age of Saturn’s rings is a matter of determining the mass of the planet, the gravitational pull of Saturn on the rings, and the mass of the rings.

    In order to directly sample the needed data points, Cassini had to fly between Saturn and the rings, something not permitted during the craft’s primary mission but that became a feature of its Grand Finale.

    By flying directly between Saturn and its rings, Cassini was able the return data that allowed scientists to calculate how much gravity was pulling on Cassini, causing it to accelerate, down to a fraction of a millimeter per second. With that information, scientists could understand the mass of the planet and the mass of the rings.

    “Only by getting so close to Saturn in Cassini’s final orbits were we able to gather the measurements to make the new discoveries,” said Cassini radio science team member and lead author Luciano Iess, of Sapienza University of Rome. “And with this work, Cassini fulfills a fundamental goal of its mission: not only to determine the mass of the rings, but to use the information to refine models and determine the age of the rings.”

    Cassini data showed the rings have a low mass, corresponding to a younger age of between 10 to 100 million years. Corroborating this is the appearance of the rings, which are bright and clean. An older ring structure would be dark and contaminated by debris.

    ____________________________________

    However, it has not just been data gathered during the Grand Finale that has continued to illuminate the Saturnian system; information collected throughout Cassini’s mission continues to be analyzed and continues to reveal new and exciting elements of the system.

    Dust storms on Titan:

    Titan is a complex world, to say the least, and the only moon in the solar system with a thick and complex atmosphere and with a hydrologic cycle. Now, the impressive moon enters a category previously reserved for only two other bodies in the solar system: the presence of dust storms on its surface.

    As on Earth and Mars, weather patterns on Titan vary from season to season, and data from Cassini throughout its mission has revealed the changing nature of Titan’s weather, including the emergence of powerful methane storms near the moon’s equator during the northern equinox in 2009.

    During this period, Sebastien Rodriguez, an astronomer at the Université Paris Diderot, France, and his team noted unusual equatorial bright spots in infrared data returned from Cassini, brightenings they interpreted at the time to be the same kind of methane clouds and storms observed on other areas of the moon during the northern equinox.

    But subsequent investigations have revealed that these brightenings were in fact something very different. They were not methane storms. They were dust storms.

    4
    Image showing dust storms. NASA/JPL Caltech, U Arizona, University Paris Diderot, IPGP, S.Rodriguez et al. 2018

    “From what we know about cloud formation on Titan, we can say that such methane clouds in this area and in this time of the year are not physically possible,” said Rodriguez. “The convective methane clouds that can develop in this area and during this period of time would contain huge droplets and must be at a very high altitude – much higher than the 6 miles (10 kilometers) that modeling tells us the new features are located.”

    Modeling and investigation revealed the features seen in 2009 where in the atmosphere but close to Titan’s surface and likely formed “a very thin layer of tiny solid organic particles.” The bright spots appearances directly over the dune fields around Titan’s equator left only a single explanation for what they actually were: clouds of dust raised from the dunes.

    “The near-surface wind speeds required to raise such an amount of dust as we see in these dust storms would have to be very strong – about five times as strong as the average wind speeds estimated by the Huygens measurements near the surface and with climate models,” noted Rodriguez.

    The presence of strong winds and confirmation of dust storms on the surface of Titan means that Titan’s dunes are still active and continually changing. Moreover, winds on Titan could be carrying dust gathered from across large distances, “contributing to the global cycle of organic dust on Titan and causing similar effects to those that can be observed on Earth and Mars”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA Spaceflight, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 2:43 pm on January 9, 2019 Permalink | Reply
    Tags: NASA is yet to release any information as to why the latest RS-25 test in December aborted just seconds into what was set to be a full duration firing., NASA Spaceflight, SLS will start using the expendable version of the engine sometimes called the RS-25E, The new rocket will first use up the stock of Space Shuttle flown veteran engines that were handed over after the conclusion of the Space Shuttle Program., The Shuttle engines – known as RS-25Ds – were designed to be reused numerous times.   

    From NASA Spaceflight: “Government MECO delays RS-25 testing following premature shutdown” 

    NASA Spaceflight

    From NASA Spaceflight

    January 9, 2019
    Chris Bergin

    1

    NASA is yet to release any information as to why the latest RS-25 test in December aborted just seconds into what was set to be a full duration firing. The lack of information partly relates to NASA employees being out of work during the current government shutdown, which has also impacted on the test schedule. However, prime contractor Aerojet Rocketdyne notes they can accommodate a “temporary” delay.

    The RS-25 will be the main engine on NASA’s next flagship rocket, the Space Launch System (SLS), which is using tried and tested heritage hardware from the Space Shuttle era.

    The engine involved with the latest test was the Development Engine 0525 (E0525).

    This engine is being used on the latest set of firing to help validate engine components – built by prime contractor Aerojet Rocketdyne – using modern, updated manufacturing techniques aimed at reducing the cost to build new “production restart” engines for delivery in the early 2020s. As such, this test series is not wholly critical to the opening launches of SLS, albeit pending the reason and potential impacts relating to the test abort.

    Numerous RS-25 hot fires have taken place on the A-1 test stand at Stennis.

    Testing from 2015 through most of 2017 helped to certify the already-built “adaptation” engines and a new engine control system to the SLS flight environment. However, beginning in December 2017, the focus of RS-25 ground testing shifted to development and certification of the “production restart” design.

    Engine 0525 is one of two development engines that have never flown in space and won’t be used with the opening salvo of launches with SLS.

    1
    As viewed in 2012, the SSMEs transferred from Shuttle to SLS. Since then, Engine 2063 has been assembled and acceptance tested at Stennis. Credit: NASA

    The new rocket will first use up the stock of Space Shuttle flown veteran engines that were handed over after the conclusion of the Space Shuttle Program.

    Four engines have been selected for each of the opening missions, with another set of four placed on standby.

    The first four RS-25s that will fly have already been selected for the Exploration Mission -1 (EM-1) maiden launch of the SLS.

    They are currently housed at the Stennis Space Center ahead of eventually being installed on the first core stage for a key validation firing on the B-2 test stand at the facility.

    This “Green Run” test will be the first time four RS-25s will have been fired up together and will act as a major milestone ahead of the core stage’s shipping to the Kennedy Space Center (KSC) for launch preparations.

    3
    The four RS-25 engines slated for Exploration Mission-1 (EM-1), the first SLS launch, at Aerojet Rocketdyne’s Stennis facility in October, 2017. Credit: Aerojet Rocketdyne.

    The Shuttle engines – known as RS-25Ds – were designed to be reused numerous times. Once the stock of RS-25D’s has been exhausted, currently expected to be in the second half of the 2020s based on the current SLS launch schedule – SLS will start using the expendable version of the engine, sometimes called the RS-25E.

    The expendable engine will be cheaper to manufacture and will adopt several elements of modern manufacturing, such as the inclusion of some 3D printed components – such as the pogo accumulator assembly.

    The tests have also been putting the new engine controller units (ECUs) through their paces.

    The engine also sports a new insulation system for the high-pressure fuel turbopump (HPFTP), which some experts have speculated could be a likely suspect for the observed fire that was seen coming from the powerhead before the engine shut down during the December test.

    An RS-25 engine just had a significant anomaly during a test fire at @NASAStennis. The test was aborted just seconds in. pic.twitter.com/77A0d8XyXK

    — Michael Baylor (@nextspaceflight) December 12, 2018

    Immediately after the abort, NASA Stennis sent out a one-line media advisory acknowledging the abort and adding safing of the engine and test stand were in progress.

    “A scheduled RS-25 engine test at NASA’s Stennis Space Center experienced an early shutdown. Post-test securing and processing are in progress,” noted Stennis.

    While Aerojet Rocketdyne forwarded requests for information to NASA Stennis, no specific information was provided.

    NASA employees – bar some relating to the ISS and other critical operations – then became the subject of the government shutdown, ending any hope for a full update for the foreseeable future.

    The last communication from NASA only added the abort was manually triggered from the control room and that an investigation was still being conducted.

    “During an RS-25 engine test on December 12, a manual early termination was initiated when data indicated an anomaly. An investigation into the incident remains underway although initial indications are that damage to the test stand and engine are limited.”

    A couple of early shutdowns have occurred during previous RS-25 hot fire tests. However, each of those have been classed as “facility” issues, where the test stand, not the engine, was at fault. The latest abort appears to be specific to the engine, pending confirmation from NASA or the contractor.

    That contractor, Aerojet Rocketdyne, did provide a statement this week, albeit specific to the shutdown and not the reasons for the RS-25’s aborted test.

    “Aerojet Rocketdyne continues to support the RS-25 adaptation and restart contracts. The shutdown has impacted the availability of NASA testing facilities; however, a temporary delay in testing can be accommodated in our schedules.”

    The key element of that statement is “temporary” as an extended shutdown will undoubtedly feed into the forever-shaky SLS schedule. Current projections for the maiden launch date of SLS and Orion on EM-1 have slipped every year, with the current challenge of keeping this launch in 2020, as opposed to the growing potential of slipping into 2021.

    One of the critical paths on the SLS schedule is the Core Stage, which will host the four RS-25s. Ensuring the engines have concluded their test series, be it for the upcoming flights and/or future iterations as an expendable unit, could play into the Core Stage schedule.

    The most positive news was the safe shutdown during the abort, which showed the test stand did not suffer any obvious damage and the engine didn’t “blow up”. This lack of a dramatic failure was referenced by former Space Shuttle Program manager Wayne Hale.

    It’s all still there. I’ve seen worse

    — Wayne Hale (@waynehale) December 13, 2018

    The next RS-25 test was set to take place over the coming days, although that has obviously been postponed indefinitely due – at least – to the government shutdown.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 4:27 pm on December 29, 2018 Permalink | Reply
    Tags: , , , , Crewed Orion spacecraft passes critical design review, NASA Spaceflight   

    From NASA Spaceflight: “Crewed Orion spacecraft passes critical design review” 

    NASA Spaceflight

    From NASA Spaceflight

    2

    In early December, NASA’s Orion Program completed a “Delta” Critical Design Review (CDR) of the crewed spacecraft configuration that will first fly on Exploration Mission-2 (EM-2). This CDR focused on the changes between the uncrewed spacecraft configuration that will fly on Exploration Mission-1 (EM-1) and EM-2.

    The CDR looked at the progress of designs for new or significantly modified Orion systems for EM-2. CDR Reviews began in September and culminated in a board meeting on December 3.

    NASA, the European Space Agency (ESA), and their U.S. and European prime contractors are looking at the Orion EM-2 schedule, which currently targets launch of a four-person crew in the second half of 2022 on a lunar flyby test flight.

    Delta CDR board on December 3

    “The vehicle came through very well on this CDR,” Kirasich said. “This CDR was focused on the differences between EM-1 and EM-2, which primarily is in two areas. The ECLSS, the Environmental Control and Life Support System, and the crew displays.”

    “Those two systems came through very clean, very few problems because predominantly the teams — even though we don’t fly them on EM-1 — we’ve been working them hard offline in labs and risk reduction development testing,” he added.

    1

    High-level overview of Orion from a NASA presentation. Credit: NASA.

    “The EM-2 CDR was intended to demonstrate the design maturity of EM-2 first use, or substantially modified hardware and software systems since the [EM-1] CDR,” Kirasich said in a follow-up email statement. “Conducted primarily in the fall of 2018, it included eight Subsystem Design Reviews (SSDRs) and four Management Review Team (MRT)/Targeted Review Team (TRT) reviews and a Face-to-Face (F2F) meeting regarding the European Service Module (ESM).”

    “This is comparable to the eight SSDRs, six MRT/TRT reviews, and ESM F2F held in support of the [EM-1] CDR in 2015.”

    The overall Delta CDR started in September. “The way it works is you will start out with component reviews, ” Kirasich explained.

    “I’ll give you an example, there will be a fan, we’ve got to have a critical design review on the fan. Then you have subsystem reviews which is the ECLSS, when you look at the fan with the mixing valve with the diffuser, how does this ECLSS system work?”

    “So you have a system-level (review),” he added. “And then we have integrated vehicle reviews that look across systems.”

    Kirasich noted that this CDR was not intended to cover systems that haven’t changed. “We didn’t go back and have another CDR on the crew module RCS (Reaction Control System) prop thruster, right? Because we’re flying that on EM-1 and that hasn’t changed,” he said.

    “But what we do have to do is, because we’re adding these new systems, they take power, they add mass to the vehicle, they add a heat load to the vehicle,” he explained. “So we have to go across the entire vehicle and we have these integration reviews where we look at, well now that we’ve added these three new fans, ‘[for] the vehicle weight do how much did it go up?’ ‘How much additional power did it consume?’”

    “So we do cross-cutting reviews, as well, and then during all these reviews when you find something you will say ‘this does not meet a requirement’ or ‘this does not meet one of the goals of the CDR’ you write something called an RFA (request for action), which then is a piece of paper that the program goes off and works,” Kirasich said.

    3
    Orion EM-2 pressure vessel in the “birdcage” tool in the Operations and Checkout Building at KSC in November. The remainder of the crew module structural elements are being added to the pressure vessel in the tool. Credit: NASA/Rad Sinyak.

    “We left the review with a total of 206 RFAs, so we accepted 206 RFAs during the review,” he added. “During the process from September until we had our board in early December we closed 37 of the RFAs just while we doing the review itself, so we left the review with 169 RFAs that we’ll then go off [and] work and regroup in late May to make sure we’ve closed all the actions out.”

    “To put that into context for you, I don’t have the exact number but when we did our first Critical Design Review for the EM-1 vehicle we had over a thousand RFAs,” Kirasich noted. “So you can see, the statistics kind of bear it out too, that the vehicle is coming together — smaller number of final things we need to work off to be ready to go into final assembly and testing.”

    EM-2 configuration changes

    The Orion Crew Module flew on the Exploration Flight Test-1 (EFT-1) mission with mass simulators for the rest of the spacecraft and without crew-support systems like ECLSS elements. Exploration Mission-1 (EM-1), currently forecast for launch in the second half of 2020, adds the Crew Module Adapter (CMA) and European Service Module (ESM) elements that provide power, supplies, and propulsion for the spacecraft to fly independently for the first time on a long-duration mission to cislunar space.

    EM-2 adds all the equipment and additional supplies to support a four-person crew up to a twenty-one day independent mission. This includes supplies of oxygen and nitrogen gas predominantly stored in the ESM and systems to manage their mixture for the basic cabin atmosphere in the Crew Module (CM).

    3

    Presentation figure showing basic layout of fully outfitted crew module, which will fly for the first time on EM-2. Credit: NASA.

    Another system in the CM filters carbon dioxide from the crew out of the atmosphere. The EM-2 vehicle design also adds the computer displays and controls to the CM for the crew to be able to monitor and operate the vehicle.

    The EM-2 CM will also have a galley for food preparation and a toilet. There will additionally be storage room for food supplies and other crew equipment.

    The second ESA Service Module that will fly on EM-2 will be largely the same as the first flight module which is being integrated with the CMA at the Kennedy Space Center (KSC) in Florida for EM-1, but prime contractor Airbus Defence and Space will be making some modifications while shaving down the overall mass of the module.

    Kirasich noted one such change is to the solar array drive mechanism. “We’re making a change to it from EM-1 to increase the amount of current that can be applied to the motors essentially to give it a stronger hold and rotational capability,” he said.

    “So we’re changing some parameters inside the FPGA (Field Programmable Gate Array) to have more torque and more margins in our solar array operations for EM-2.”

    4
    Graphic showing the canting angle extremes of the solar array wings (SAW) on the ESM. The drive electronics for the solar arrays are being upgraded with the EM-2 vehicle for future rendezvous and docking missions. Credit: NASA.

    Nujoud Merancy, NASA Exploration Mission Analysis Lead, elaborated further: “You have the inner gimbal, so that is the shoulder joint that moves the array forward and aft, it has enough torque and resistance to handle a lot of what’s going on on EM-1 but then when we looked at EM-3 and beyond really for the rendezvous we end up having to park it a lot because of all the burns,” she said. “To get through a rendezvous there’s a lot of burns as you approach another vehicle.”

    “The combination of the need to park it which takes away from power production and then move it so you can get power and then stop it again for burns, it’s a really good improvement to the overall system operability to just make that gimbal a little bit stronger so that you can keep it tracking through more of the burns,” she explained.

    Another forward looking change is to repoint of some of the RCS thrusters to help with Orion attitude control when maneuvering while docked with a module that it is delivering to the future cislunar gateway. “Realigning the RCS is not a major change,” Merancy noted.

    “But those aft RCS that are out at a ’45’ [degree angle] right now on the pitch and yaw axes if you point them into the pure pitch direction we’ll have more control authority for rendezvous and docking with the co-manifest payload,” she explained.

    A third change adds some redundancy to the ESM propellant system, which adds value when crews start flying on Orion. “The prop system has to be pressurized with upstream helium tanks and right now those two helium systems upstream are independent of each other,” Merancy noted.

    5
    “The idea is that if you add a crossfeed so you can feed from one helium tank to another, if you have a blockage or a leaky valve downstream from one tank you could still retain the performance of that helium by crossfeeding it into the other one,” she said.

    “It’s not something you would nominally use, but it’s something that would improve reliability for a contingency.”

    A recently noted change for the EM-2 CMA is incorporating lessons learned from assembly of the EM-1 flight structure.

    “There’s an inner ring that is, if you will the inner structural article that essentially provides the inner structural member,” Kirasich explained. “For EM-1, we had designed that out of six different pieces, you might imagine six different sixty-degree pieces.”

    “The challenge we had on EM-1 was during assembly in the O&C (Operations and Checkout) Building in Florida. We would hang these parts in the tool, so there’s an inner ring, there’s upper panels, there’s lower panels, and there’s an outer ring and all these things came in pieces.”

    6
    “We had alignment issues, not only between the parts that had to mate between [the panels and the rings] but also with each other,” he noted. “So what we did in an attempt to improve manufacturability was instead of these six sixty-degree inner wall panels, we are going to have a single 360-degree inner wall.”

    “We start with a single piece of aluminum, it’s a forging and we send it to a machine shop that machines out of a single piece instead of six different pieces.”

    EM-2 Orion hardware status

    The EM-2 Orion spacecraft elements are largely still in structural assembly. The completed Crew Module pressure vessel was delivered to the O&C Building at KSC in late August, where Orion prime contractor Lockheed Martin assembles the Crew Module and CMA and performs final spacecraft assembly.

    The CM pressure vessel is currently being outfitted with other structural elements in the birdcage stand. The inner ring/inner wall of the CMA structure is expected to be shipped to KSC soon.

    “It’s being machined for Lockheed Martin by a company called Ingersoll in Rockford, Illinois, and the reason I know this is because whenever we do something like this that is a primary structural component, it’s a pretty big deal and we worry about it so we watch it very closely,” Kirasich said. “We are really close [to completion]. They’ve actually done a tremendous job.”

    7
    The partially-outfitted structure for ESM Flight Model-2 (FM-2), which is slated for the EM-2 mission, is moved into the integration stand at the Airbus assembly, integration, and testing facility in Bremen in late November. Credit: Airbus Defence and Space.

    “Then when Ingersoll is done it goes to a finishing shop where they put a primer on it and it’ll be at the Cape in January, so we’re about done with that inner ring and then it’ll be down at the Cape installed in that tool and we’re going to see if this did indeed improve our manufacturability.”

    Assembly, integration, and testing (AIT) of the second ESM, Flight Model-2 (FM-2), continues at ESM prime contractor Airbus Defence and Space’s AIT facility in Bremen, Germany. With shipment of Flight Model-1 from Bremen in early November, FM-2 took its place in the integration stand in early December.

    At the time of the ESM FM-1 arrival in Florida in November, Airbus was forecasting completion of FM-2 in the first quarter of 2020.

    Removing iron bars

    The overall assessment of the EM-2 launch date target is currently September, 2022, with the different Exploration programs (Exploration Ground Systems, Orion, Space Launch System) looking at schedules for EM-1 and EM-2 dependencies on that first integrated flight.

    Funding for a second Mobile Launcher (ML) set in motion a series of updates and changes to the EM-2 mission and its launch date. Prior to the changes, there was a 33-month “iron bar” in the schedule between EM-1 and EM-2 to modify the first ML for a new Space Launch System (SLS) upper stage.

    With the EM-2 test flight moved back to the first, interim SLS upper stage, the target launch date could be made somewhat independent of when EM-1 finally launches and forecast date moved from 2023 back into 2022. But there are still some dependencies EM-2 has for when EM-1 launches, such as reuse of Orion avionics boxes.

    8
    Long-term Orion program planning chart from early 2018 showing the “avionics refurb” from EM-1 to EM-2 (top middle). With the EM-1 launch date moving into the second half of 2020, the program is buying a second set of core avionics earlier than planned to maintain EM-2 schedule margin. Credit: NASA.

    While the forecast date for EM-2 improved with the move back to the SLS Block 1 configuration, the forecast for the EM-1 launch date has continued to slide which has shrunk the estimated time between launches. “So when EM-1 slipped, it reached the point where the time to pull the boxes out of EM-1 and insert them into the EM-2 crew module and test them, that was starting to drive the EM-2 launch date,” Kirasich noted.

    NASA is trying to advance the target date for the EM-2 launch closer to the mid-2022, and the Orion Program is looking at ways to optimize the schedule for assembly, integration, and testing of the EM-2 vehicle for launch. To reduce the dependence of EM-2 Orion vehicle processing on when EM-1 flies, they looked at advancing the purchase and assembly of the set of EM-3 avionics.

    The original plan was to build the second full set of crew module avionics with construction of the EM-3 spacecraft that will fly after EM-2. “Once we get done with DDT&E (Design, Development, Test and Evaluation) we want to fly once a year and we’re trying to do it very economically and efficient, so we’re trying to reuse as many components from flight to flight as we can,” Kirasich explained.

    “Almost like Shuttle did — you know in the Shuttle every orbiter we had one set of avionics, and unless something broke you reflew the avionics all the time,” he continued. “So the intent when we get into routine operations is we’re going to have three primary structures and three sets of avionics that fly together all the time, that’s our goal.”

    “We looked at how much funding that would take to accelerate those EM-3 boxes and then we all said ‘boy that would take money away from all other things on EM-2, do I need to buy all [of them] or can I buy a subset?’,” Kirasich said.

    It turned out that accelerating only the Orion Core avionics would allow much of the EM-2 Orion integration and checkout to continue independently of EM-1. “The Core consists of the computers, the VMCs (Vehicle Management Computers), and the PDUs (Power Data Units), and actually one or two other boxes which are called media converters,” he explained.

    Gary Cox, NASA Orion Avionics Power and Wiring Manager, said in an email that the number of avionics boxes in the core set is 11, leaving 15 boxes that will be re-used from EM-1 to EM-2.

    “So we’re able to have new boxes, we’re going to put them in, that allows us to turn the vehicle on for the first time on schedule, if you will, without being affected by EM-1,” Kirasich said. “Now let’s go back to our earlier conversation about ECLSS and crew displays. We have new avionics boxes showing up for the first time, the ECLSS controllers and the crew displays.”

    8

    Development version of the Orion crew displays as seen at Johnson Space Center in April, 2018. Credit: Philip Sloss for NSF/L2.

    “They will be able to get plugged in early, so we will be able to do the first vehicle power on and we will also be able to do the first vehicle checkouts of the new components, the ECLSS controllers and the crew displays, completely independent of when EM-1 flies,” he noted.

    “So for approximately half the price of accelerating the whole EM-3 [avionics set], that allowed us to decouple EM-1 from EM-2, it bought us well over six months of decoupling,” Kirasich added.

    In terms of the Orion EM-2 vehicle schedule, Kirasich said his bosses are asking the Exploration programs if they can advance the launch date. “[They] have asked us to try and pull it back to June and we’re working very hard at that action they’ve given us,” he said.

    “I am going to be able to pull it back, I’ll be able to do better than September. I don’t know if I’ll be able to get all the way back to June but that’s what I’m working on.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 1:33 pm on December 9, 2018 Permalink | Reply
    Tags: NASA Spaceflight, NROL-71 mission, ULA Delta IV   

    From NASA Spaceflight: “ULA Delta IV-Heavy scrubs at T-7 seconds ahead of launch with NROL-71 mission” 

    NASA Spaceflight

    From NASA Spaceflight

    December 7, 2018
    William Graham

    1
    United Launch Alliance’s Delta IV Heavy rocket will try again next week to launch the mysterious NROL-71 mission for the National Reconnaissance Office following two scrubs. Friday’s initial attempt was scrubbed after ULA noted an issue with the hold-fire circuitry – specifically a redundant communication link between the control center and the launch site – required further work. Following a 24 hour recycle, all was proceeding to plan until T-7 seconds when an abort was trigged. It is not yet known when the next attempt will take place.
    Like most activities conducted by the United States National Reconnaissance Office (NRO), specifics of the NRO Launch 71 (NROL-71) mission are classified. The NRO is the organization that operates America’s fleet of reconnaissance and intelligence-gathering satellites, using a variety of spacecraft types and surveillance techniques to support national defense and security.

    Despite the classified nature of their operations, a combination of information published by the NRO itself and other government sources, leaks and observation of the satellites’ orbits and behavior has allowed different groups of satellites to be characterized and their purpose determined. Analysis of hazard areas published for maritime and aviation safety in advance of every launch, combined with a comparison of the type of rocket to be used to those that have orbited previous satellites, allows most NRO satellites to be identified before they even leave the ground – although occasionally a mission will throw a curveball.

    NROL-71 has proven one such mission. Before the launch time and hazard areas were published it was a safe bet that this launch would add a new member to the NRO’s fleet of KH-11, or Crystal, imaging satellites. Also formerly codenamed Kennen, Key Hole 11 (KH-11) spacecraft collect incredibly high-resolution images of the Earth’s surface and transmit them back to the ground for analysis. Originally developed in the 1970s, but upgraded over time, the KH-11 is among the largest satellites that the NRO operates and requires one of America’s most powerful rockets, the Delta IV Heavy, to place it into orbit.

    2
    Delta IV-Heavy ahead of this mission-via ULA

    The near-polar sun-synchronous orbits used by Crystal satellites dictate that they must be launched from California, as to launch from Florida would either require the rocket to fly – and potentially drop debris – over land, or to avoid this by making a dogleg maneuver which would affect its performance.

    As Crystal is the only type of satellite to have launched aboard a Delta IV Heavy from the West Coast, the launch was widely expected to carry a replacement for the oldest satellite in the constellation. But instead of the south-westerly trajectory required to reach Crystal’s sun-synchronous orbit, hazard areas for the NROL-71 mission show that the rocket will follow a south-easterly track towards an orbit inclined at about 74 degrees. Aside from a 2010 technology demonstration mission, no US military satellite has operated in an orbit close to this inclination since 1971.

    That 2010 mission was STPSat-2, which was flown in a 72-degree orbit by the Space Test Program to test sensors and data relay systems in space. It is unlikely to be related to the NROL-71 mission. Before 1971 a 75-degree orbit was used for a small proportion of the NRO’s fleet of KH-4 Corona imaging satellites as well as seven “heavy ferret” electronic signals intelligence (ELINT) satellites and two photoreconnaissance satellites of the short-lived KH-6 Lanyard project. The Soviet Union operated Zenit photoreconnaissance satellites in 73-degree orbits from 1966 until 1989, along with ELINT, calibration, communications and geodesy satellites in similarly-inclined orbits whose launches were continued by Russia until the early 2000s.

    The use of a Delta IV Heavy means that the NROL-71 payload must either be too heavy to be deployed by any of the other rockets qualified to carry out the NRO’s most expensive and critical missions or destined for a sufficiently high orbit as to require the services of this behemoth rocket.

    The only high orbits typically of value for reconnaissance are an elliptical Molniya orbit, which allows eavesdropping satellites to loiter over high latitudes for much of their time, and geostationary orbit. NROL-71 will target neither of these – Molniya orbits require a precise inclination of 63.4 degrees, while geostationary trajectories require that the rocket launch almost due East which is not practical from Vandenberg – meaning that its payload is likely a heavy satellite.

    Despite the unusual orbit, a KH-11 is still a likely candidate for the identity of the NROL-71 payload. The less-inclined orbit could allow the satellite to spend more time over lower latitudes instead of passing over the polar oceans and icecaps. Not having the satellite in a sun-synchronous orbit would also allow it to view areas of interest at different times of the day with objects on the surface casting shadows in different directions. A Crystal in such an orbit could be intended to compliment the sun-synchronous element of the constellation, or may signal a move away from SSO for this program.

    4

    If NROL-71 does deploy a Crystal satellite, it will be the seventeenth such spacecraft to launch. The KH-11 was developed as a continuation to the long-running series of Key Hole satellites that had begun with early Corona imaging spacecraft in the 1950s. It was the first Key Hole not to use film capsules, downlinking images electronically instead of physically sending them back to Earth for processing.

    The first KH-11, OPS 5705, was deployed by a Titan rocket in December 1976. Initially KH-11 operated alongside the film-return KH-8 Gambit and KH-9 Hexagon satellites, which provided high-resolution and wide-area imaging capabilities respectively, but eventually the new satellites assumed both of these roles.

    The design of the Hubble Space Telescope was reportedly influenced by Crystal, with Hubble’s mirrors being designed to take advantage of production techniques – and possibly hardware – developed for the reconnaissance programme. The KH-11 satellites are also said to have similar proportions and appearance to Hubble.

    Four distinct “blocks” of KH-11 satellites have been identified. The first two blocks consisted of five and four satellites respectively, launched aboard Titan III(34)D rockets. Block III was designed to be launched by the Space Shuttle, however following the loss of Challenger polar-orbit Shuttle missions were abandoned and the Titan IV rocket was developed instead. The most recent upgrade, Block IV, was first flown in 2001.

    The fourteenth Crystal mission, NROL-20 or USA-186, was launched by the final Titan IV rocket and was expected to be the last KH-11 to fly. The National Reconnaissance Office had intended to procure a next-generation optical imaging satellite through its Future Imagery Architecture (FIA) program, but after this collapsed the agency purchased two additional KH-11s, built in part from leftover spares, to serve as a stopgap until a new system could be developed. When the first of these launched, aboard a Delta IV Heavy in 2011, its mission patch bore the Latin inscription “melior diabolus quem scies” – better the devil you know.

    More recent rumors have suggested that the NRO has opted to buy a fifth generation of Crystal satellites instead of developing a replacement from scratch. These could incorporate more modern technologies and benefit from the increased performance of Delta IV over Titan IV to carry more fuel, which would allow them to maintain lower orbits than their predecessors. If NROL-71 is a KH-11, it will certainly be the first member of this new generation.

    Another possibility is that NROL-71 may be a successor to the stealthy Misty imaging satellites that were launched in 1990 and 1999. Believed to be an offshoot of the Crystal series, the first Misty satellite was USA-53, deployed from Space Shuttle Atlantis during 1990’s STS-36 mission.

    After deployment, USA-53 shed debris – leading to reports that it had failed – and maneuvered to a different orbit. During its lifetime, amateur observers lost track of – and subsequently rediscovered – Misty several times with the last sighting in 1997.

    A second Misty, USA-144, was launched in May 1999 aboard a Titan IV(404)B. After deployment the satellite released a decoy and then disappeared – despite the efforts of the amateur satellite watching community, USA-144 was never found. It is unclear whether this spacecraft is still in orbit.

    The Misty satellites operated in orbits with significantly lower inclination than Crystal: USA-53 used a 65-degree orbit and USA-144 was deployed into a 63-degree orbit, although its final destination is unknown. They are believed to be among the most expensive satellites ever launched, and development of a third Misty satellite was canceled in the mid-2000s due to the project’s cost.

    5
    Misty schematic

    Observations of the NROL-71 payload, which is expected to be named USA-289 once it reaches orbit, will likely reveal more about its identity and mission. A lack of observations could point towards it being another Misty satellite.

    The Delta IV Heavy that will be used for the NROL-71 mission is the heaviest rocket currently certified to carry out national security launches of this nature.

    A two-stage vehicle, Delta IV consists of a Common Booster Core (CBC) first stage and a Delta Cryogenic Second Stage (DCSS), which both burn cryogenic propellant: liquid hydrogen and liquid oxygen.

    The rocket can be flown in five different configurations depending on the mass and dimensions of its payload and the target orbit. The smallest of these, the Delta IV Medium, used a four-meter diameter upper stage and no boosters, while three Medium+ versions – M+(4,2), M+(5,2) and M+(5,4) added two or four solid rocket motors and in the latter two cases a five-meter upper stage.

    The Delta IV Heavy uses three Common Booster Cores strapped together, with the center core operating at partial thrust for much of its flight to extend its burn beyond that of the two outboard cores. It is the only version of the Delta that is expected to continue flying past the end of next year, as the Medium configuration has already been retired and the Medium+ versions of the rocket are being phased out. United Launch Alliance will instead focus on offering launch services in these classes with its Atlas V rocket, before introducing a new rocket – Vulcan – to replace both Atlas and Delta in the family.

    The launch will use the west-coast Delta IV launch pad, Space Launch Complex 6 (SLC-6) at Vandenberg Air Force Base. SLC-6 was originally developed in the 1960s for the Titan family of rockets, specifically to support the Manned Orbiting Laboratory (MOL) military space station. When MOL was canceled, SLC-6 was mothballed. It would later be reconstructed to support Space Shuttle missions to polar orbits, however risk reduction following the Challenger accident eliminated these plans and the complex once again went unused.

    7

    The first launch from SLC-6 finally came in August 1995, when Lockheed launched the first flight of the Lockheed Launch Vehicle 1 (LLV-1), which would later be named Athena. This launch failed, and while the next launch from the pad successfully placed NASA’s Lewis satellite into orbit the payload suffered an unrecoverable malfunction three days later. This, along with another launch failing in April 1999, led to a myth that the launch pad was cursed. The fourth and final Athena mission from SLC-6, in August 1999, successfully delivered a healthy satellite to orbit.

    Boeing began converting SLC-6 for its Delta IV rocket in the early 2000s. Delta first used the complex in June 2006 and has made seven launches from Vandenberg prior to this mission, two of which have been in the Heavy configuration. This will be the first west-coast launch for a Delta IV Heavy with RS-68A engines, an upgraded version of the RS-68 Overall, this launch will be the thirty-eighth flight of Delta IV and the eleventh Heavy.

    The NROL-71 launch will begin with the ignition of the RS-68A engines that power the three Common Booster Cores.

    8
    Delta IV-Heavy powers up by Nathan Baker for NSF/L2

    The starboard core will ignite seven seconds before the scheduled liftoff, with the port and center boosters igniting two seconds later at T-5. This staggered ignition is intended to mitigate a fireball that can form around the rocket on startup as a result of hydrogen boiling off the rocket. Liftoff will occur at the zero mark in the countdown.

    After pitching over onto a south-easterly azimuth of about 168 degrees, Delta IV will pass through the area of maximum dynamic pressure – Max-Q – shortly before it reaches Mach 1 – the speed of sound – 82 seconds into the flight.

    The three CBCs will power the rocket for the first three minutes and fifty-six seconds of the flight, with the port and starboard boosters burning at full thrust and the center core at partial thrust. When the two outboard cores deplete their propellant, their engines will shut down, and the spent cores will separate two seconds later.

    Once the port and starboard boosters have separated, the center core will throttle up and burn at full power for most of the remaining two minutes of first-stage flight. Seven seconds after main engine cutoff (MECO), the first stage will be jettisoned and the second stage will enter its prestart sequence. The RL10B-2 engine will ignite twelve seconds after stage separation. Eleven seconds later, Delta IV’s payload fairing will separate from the nose of the rocket, exposing the payload to space for the first time.

    Owing to the classified nature of this mission, United Launch Alliance has not published a timeline for mission events following fairing separation and as is normal for NRO flights all official coverage of the mission is expected to conclude at this point other than a press release confirming a successful launch some time after spacecraft separation. The second stage will likely make a single burn, lasting around 12 minutes, before separating its payload into low Earth orbit. An additional launch hazard area to the northwest of Vandenberg suggests that the second stage will be deorbited into the Pacific shortly after separation.

    This launch is the last of 2018 for United Launch Alliance, ending a year in which the company has flown four Atlas V and three Delta IV rockets, as well as the final flight of its venerable Delta II vehicle. NROL-71 is the second launch of the year to use a Delta IV Heavy, following the deployment of NASA’s Parker Solar Probe in August.

    The next launch for both United Launch Alliance and the Delta IV is currently slated for 23 January, when the rocket’s Medium+(5,4) configuration will be used for the last time to loft a Wideband Global Satcom communications satellite for the US Air Force. The next Delta IV Heavy mission is expected to fly from Vandenberg in mid-2020.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 5:58 pm on October 25, 2018 Permalink | Reply
    Tags: , NASA Spaceflight,   

    From NASA Spaceflight: “Two NASA space telescopes returning to work following sick days” 

    NASA Spaceflight

    From NASA Spaceflight

    October 23, 2018
    Chris Bergin

    1
    NASA/ESA Hubble

    Two flagship space telescopes are returning to their respective operations after they both entered safe mode around the same time earlier this month. The Hubble Space Telescope is close to moving back into normal science observations following a gyro issue, while the Chandra Space Telescope has now resumed its detections of X-ray emissions from very hot regions of the universe.
    Hubble was the first to report a problem back on October 5, relating to a backup gyroscope that was incorrectly returning extremely high rotation rates. Hubble’s gyros measure the speed at which the spacecraft is turning, and is needed to help Hubble turn and lock on to new targets.

    The Hubble Space Telescope is one of the most famous spacecraft ever launched by NASA and is closing it on its 30th anniversary since launch.

    Shuttle Discovery – STS-31 in 1990 – was Hubble’s ride into space, with her crew including former NASA Administrator Charlie Bolden, reaching a 380 statute mile orbit – higher than most orbiters would normally head to in space.

    Giving birth to Hubble on orbit didn’t go as smoothly as was hoped, as one of the observatory’s solar arrays stopped as it was unfurling. The plan for such a scenario was to conduct a contingency spacewalk. However, the ground teams eventually persuaded the array to deploy.

    2
    Hubble deployment during Discovery’s mission via L2 Historical.

    While Discovery completed her mission – and landed at Edwards Air Force Base in California on April 29 in 1990 – scientists were eagerly waiting to get their hands on the first images from the latest NASA hardware in space.

    Those first images showed Hubble had a problem.

    Ultimately, Discovery’s mission was a success, but the images revealed Hubble’s main mirror had been ground incorrectly, effectively compromising Hubble’s eyesight. A major effort was undertaken to fix the problem, via another Shuttle mission.

    It was Discovery’s younger sister that came to the rescue of Hubble in 1993, as Endeavour launched on only her fifth mission to carry out a critical service mission, with the main goal of correcting the telescope’s impaired vision.

    STS-61’s five grueling EVAs in a row successfully installed a corrective optics package – along with new solar arrays – during the highly complex 11-day mission.

    3
    Endeavour to the rescue during repair mission to Hubble – via L2 Historical.

    Hubble was back to full health and started to provide the stunning images of the cosmos that have fascinated the entire human race ever since.

    Discovery would return to Hubble in 1997, as STS-82’s mission upgraded the telescope’s scientific instruments and increased its research capabilities. Discovery would visit her favorite telescope once again on the third servicing mission in 1999, replacing all six of Hubble’s gyroscopes – three of which had failed – along with replacing a Fine Guidance Sensor (FGS) and the telescope’s computer.

    In what was Columbia’s penultimate mission prior to her tragic loss, STS-109 carried out the fourth servicing mission in 2002, with each visit extending the life of the telescope.

    The five-EVA mission installed the Advanced Camera for Surveys (ACS), new rigid Solar Arrays (SA3), a new Power Control Unit (PCU) and a new Cryocooler for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Columbia also provided Hubble with a farewell push, as the orbiter reboosted the telescope to a higher orbit.

    NASA Hubble Advanced Camera forSurveys

    NASA/Hubble NICMOS

    However, due to Columbia’s loss the following year, NASA managers were left with a dilemma, one that was likely to result in the telescope deorbited.

    Hubble was next scheduled to be serviced in 2005, yet NASA’s own Return To Flight (RTF) rules insisted on the “safe haven” requirement, allowing for an orbiter, damaged during launch, to fly to the International Space Station (ISS) for its crew to wait for another shuttle to bring them home safe.

    Based on these rules, then-NASA Chief Sean O’Keefe resisted the calls for Hubble to be serviced, whilst noting an alternative mission using robotic assets would not be developed in time to save the telescope. Hubble’s gyroscopes were expected to fail – and its batteries to run out – no later than 2010.

    Mr. O’Keefe’s successor, Mike Griffin, noted the NASA stance was based mainly on the understandable pain associated with losing Columbia and the need to not take any unnecessary chances with the orbiters and their crews during the final era of their service.

    As it stood, NASA was expected to press ahead with a plan to deorbit Hubble into the Pacific Ocean.

    Thankfully, the Return To Flight of the Shuttle fleet showed the array of safety improvements allowed for the final Hubble Servicing Mission (SM-4) to be re-evaluated. However, the challenge of launching a mission without the Safe Haven of the ISS being available needed to be solved.

    That solution came in the form of another Shuttle, ready to launch within days of a problem on an elaborate rescue mission.

    Administrator Griffin eventually approved SM-4 for Atlantis and STS-125, after the Space Shuttle Program (SSP) started to prove its new safety measures were working – such as the increasing the mitigation of External Tank foam loss and advances in Thermal Protection System (TPS) inspection, along with repair techniques – during the opening salvo of post-RTF missions.

    The best possible crew were assigned to Atlantis for the final rendezvous between the world-famous vehicles, led by commander Scott Altman, assisted by six crewmembers that included John Grunsfeld and Mike Massimino.

    Endeavour would also receive a co-star role by standing by as the STS-400 rescue mission, seeing her sat on Pad 39B ready to launch at short notice in the event Atlantis’ launch – from Pad 39A – suffered a major issue during the ride uphill on what proved to be a delayed launch date, as Hubble itself worked through problems on orbit.

    That contingency wasn’t required, as Atlantis and her crew conducted a flawless launch and rendezvous with Hubble in May 2009 – no easy task even under nominal conditions, as the orbiters use up nearly half of their prop capability just to reach the “height” of the telescope’s orbit and can endure higher MMOD risks.

    The 14-day mission involved five back-to-back EVAs, including its own challenges – highlighted by Massimino literally using brute force to pull off the STIS handrail from the telescope during EVA-4.

    However, the mission achieved all of its primary goals, including the installation of two new instruments, namely the Cosmic Origins Spectrograph (COS) and the Wide Field Camera 3 (WFC 3), leaving Hubble in a great condition to continue its role for many years to come.

    NASA Hubble Cosmic Origins Spectrograph

    NASA/ESA Hubble WFC3

    NASA explained that a wheel inside the gyro spins at a constant rate of 19,200 revolutions per minute. This wheel is mounted in a sealed cylinder, called a float, which is suspended in a thick fluid. Electricity is carried to the motor by thin wires, approximately the size of a human hair, that are immersed in the fluid. Electronics within the gyro detect very small movements of the axis of the wheel and communicate this information to Hubble’s central computer.

    These gyros have two modes – high and low. High mode is a coarse mode used to measure large rotation rates when the spacecraft turns across the sky from one target to the next. Low mode is a precision mode used to measure finer rotations when the spacecraft locks onto a target and needs to stay very still.

    In an attempt to correct the erroneously high rates produced by the backup gyro, the Hubble operations team executed a running restart of the gyro on October 16. This procedure turned the gyro off for one second and then restarted it before the wheel spun down. The intention was to clear any faults that may have occurred during startup after the gyro had been off for more than 7.5 years. However, the resulting data showed no improvement in the gyro’s performance.

    “On October 18, the Hubble operations team commanded a series of spacecraft maneuvers, or turns, in opposite directions to attempt to clear any blockage that may have caused the float to be off-center and produce the exceedingly high rates. During each maneuver, the gyro was switched from high mode to low mode to dislodge any blockage that may have accumulated around the float,” NASA added.

    4
    Hubble’s gyros overview – via ESA

    Following the October 18 maneuvers, the team noticed a significant reduction in the high rates, allowing rates to be measured in low mode for brief periods of time. The following day, the operations team commanded Hubble to perform additional maneuvers and gyro mode switches, which appear to have cleared the issue. Data showed the gyro rates now look normal in both high and low mode.

    Hubble then executed additional maneuvers to make sure that the gyro remained stable within operational limits as the spacecraft moved. The team saw no problems and continued to observe the gyro through the weekend to ensure that it remained stable.

    “The Hubble operations team plans to execute a series of tests to evaluate the performance of the gyro under conditions similar to those encountered during routine science observations, including moving to targets, locking on to a target, and performing precision pointing. After these engineering tests have been completed, Hubble is expected to soon return to normal science operations,” NASA said.

    Meanwhile, the Chandra X-ray Observatory has returned to science operations.

    Chandra’s launch was the most eventful element of the spacecraft’s early days, with Shuttle Columbia having several tantrums before finally lofting the spacecraft into space.

    STS-93 suffered an abort just seconds prior to the initial launch attempt, before finally launching on 23 July 1999 from KSC’s 39B. Eileen Collins became the first female shuttle Commander on this flight.

    Problems were noted immediately after liftoff, when a gold pin – used to plug an oxidizer post in Columbia’s right engine – came loose and was violently ejected during ignition, striking the engine nozzle’s inner surface and tearing open three cooling tubes containing hydrogen – causing a leak. An electrical short in the center engine’s primary controller also kept controllers busy, before Columbia made it to orbit, albeit ending with a LOX Level Cutoff.

    The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space observatory.

    Chandra is 19 years old, which is well beyond the original design lifetime of 5 years. In 2001, NASA extended its lifetime to 10 years. It is now well into its extended mission and is expected to continue carrying out forefront science for many years to come.

    As with Hubble, a gyro was believed to be the issue relating to entering safe mode on October 10.

    Safe mode involves putting the observatory into a safe configuration, where critical hardware is swapped to backup units, the spacecraft points so that the solar panels get maximum sunlight, and the mirrors point away from the Sun.

    “Analysis of available data indicates the transition to safe mode was normal behavior for such an event. All systems functioned as expected and the scientific instruments are safe. The cause of the safe mode transition (possibly involving a gyroscope) is under investigation,” NASA noted at the time.

    6
    An overview of Chandra – via NASA

    Five days later, the cause of Chandra’s safe mode event was understood and the Operations team successfully returned the spacecraft to its normal pointing mode. The safe mode was caused by a glitch in one of Chandra’s gyroscopes resulting in a 3-second period of bad data that in turn led the onboard computer to calculate an incorrect value for the spacecraft momentum. The erroneous momentum indication then triggered the safe mode.

    “The team has completed plans to switch gyroscopes and place the gyroscope that experienced the glitch in reserve. Once configured with a series of pre-tested flight software patches, the team will return Chandra to science operations which are expected to commence by the end of this week,” NASA added.

    That remedy appears to have worked, as on Tuesday NASA noted that Chandra had returned to science operations, with more details to follow later in the week.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 9:33 am on September 22, 2018 Permalink | Reply
    Tags: , , , , NASA Spaceflight, , NASA/MIT TESS finds 1st two exoplanet candidates during first science orbit, , TESS in excellent health,   

    From NASA Spaceflight: “TESS in excellent health, finds 1st two exoplanet candidates during first science orbit” 

    NASA Spaceflight

    From NASA Spaceflight

    September 20, 2018
    Chris Gebhardt

    1
    The joint NASA / Massachusetts Institute of Technology (MIT) Transiting Exoplanet Survey Satellite, or TESS, has completed its first science orbit after launch and orbital activations/checkouts. Unsurprisingly given TESS’s wide range of view, a team of scientists have already identified the planet-hunting telescope’s first two exoplanet candidates.
    No image credit.

    The yet-to-be-confirmed exoplanets are located 59.5 light years from Earth in the Pi Mensae system and 49 light years away in the LHS 3844 system.

    TESS’s overall health:

    Following a successful launch on 18 April 2018 aboard a SpaceX Falcon 9 rocket from SLC-40 at the Cape Canaveral Air Force Station, Florida, TESS was injected into an orbit aligned for a gravity assist maneuver one month later with the Moon to send the telescope into its operational 13.65-day orbit of Earth.

    TESS’s orbit is highly unique, with the trajectory designed so the telescope is in a 2:1 resonance with the Moon at a 90° phase offset at apogee (meaning the telescope maintains a separation from the Moon so the lunar gravity field doesn’t perturb TESS’ orbit but at the same time keeps the orbit stable) to allow the spacecraft to use as little of its maneuvering fuel as possible to achieve a hoped-for 20 year life.

    At the time of launch, mission scientists and operators noted that first light images were expected from TESS in June 2018 following a 60-day commissioning phase.

    While it is not entirely clear what happened after launch, what is known is that the commissioning phase lasted 27 days longer than expected, stretching to the end of July. TESS’ first science and observational campaign began not in June but on 25 July 2018.

    By 7 August, the halfway point in the first science observation period, TESS took what NASA considers to be the ceremonial “first light” images of the telescope’s scientific ventures.

    TESS acquired the image using all four cameras during a 30-minute period on Tuesday, 7 August. The images include parts of a dozen constellations from Capricornus to Pictor, both the Large and Small Magellanic Clouds, and the galaxies nearest to our own.

    2
    Ceremonial first light image captured by TESS on 7 August 2018 showing the full Sector 1 image (center) and close-ups of each of the four camera groups (left and right) Credit NASA/MIT/TESS

    “In a sea of stars brimming with new worlds, TESS is casting a wide net and will haul in a bounty of promising planets for further study,” said Paul Hertz, astrophysics division director at NASA Headquarters. “This first light science image shows the capabilities of TESS’ cameras and shows that the mission will realize its incredible potential in our search for another Earth.”

    George Ricker, TESS’ principal investigator at the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research, added, “This swath of the sky’s southern hemisphere includes more than a dozen stars we know have transiting planets based on previous studies from ground observatories.”

    While TESS orbits Earth every 13.65 days, its data collection phase for each of its 26-planned observation sectors of near-Earth sky lasts for two orbits so the telescope can collect light data from each section for a total of 27.4 days.

    With science operations formerly commencing on 25 July, the first observational campaign stretched to 22 August.

    Unlike some missions which only transmit data back to Earth after observational campaigns end, TESS transmits its data both in the middle and at the end of each campaign when the telescope swings past its perigee (closest orbital approach to Earth).

    On 22 August, after TESS completed its first observation campaign of a section of the Southern Hemisphere sky, the telescope transmitted the second batch of light data to Earth through the Deep Space Network.

    From there, the information was processed and analyzed at NASA’s Science Processing and Operations Center at the Ames Research Center in California – which provided calibrated images and refined light curves for scientists to analyze and find promising exoplanet transit candidates.

    NASA and MIT then made that data available to scientists as they search for the more than 22,000 exoplanets (most of those within a 300 light-year radius of Earth) that TESS is expected to find during the course of its two-year primary mission.

    First TESS exoplanet candidate:

    Given the sheer number of exoplanets TESS is expected to find in the near-Earth neighborhood, it is not surprising that the first observation campaign has already returned potential exoplanet candidates – the first of which was confirmed by NASA via a tweet on Wednesday, 19 September.

    TESS’ first exoplanet candidate is Pi Mensae c – a super-Earth with an orbital period of 6.27 days. According to a draft of the paper announcing the discovery, several methods were used to eliminate the possibility of this being a false detection or the detection of a previously unknown companion star.

    The Pi Mensae system is located 59.5 light years from Earth, and the new exoplanet – if confirmed – would be officially classified Pi Mensae c, the second known exoplanet of the system.

    Exoplanet’s official classifications derive from the name of the star they orbit followed by a lowercase letter indicating the order in which they were discovered in a particular system.

    The order in which exoplanets are discovered does not necessarily match the order (distance from closest to farthest) in which they orbit their parent star.

    Moreover, the lowercase letter designation begins with the letter “b”, not the letter “a”. Thus, the first discovered exoplanet in a particular system will bear the name of its parent star followed by a lowercase “b”.

    Subsequent exoplanets orbiting the same start or stars (as the case may be), regardless of whether they orbit closer to or farther away from the parent star than the first discovered exoplanet will then bear the letters c, d, e, etc.

    3
    NASA/Ames – Wendy Stenzel

    Therefore, confirmation of the new exoplanet candidate in the Pi Mensae system would make the planet Pi Mensae c.

    Pi Mensae b, a superjovian, was discovered on 15 October 2001 using the radial-velocity method of detection via the Anglo-Australian Telescope operated by the Australian Astronomical Observatory at Siding Spring Observatory.

    In the search for exoplanets, two general methods of detection are used – direct observation of a transiting exoplanet that passes between its star and the observation point on or near Earth (the method employed by TESS) and the radial-velocity, or doppler spectroscopy, method of detection which measures the wobble or gravitational tug on a parent star caused by an orbiting planet that does not pass between the star and the observation point on or near Earth.

    Overall, roughly 30% of the total number of known exoplanets have been discovered via the radial-velocity method, with the other 70% being discovered via the transiting method of detection.

    Radial Velocity Method-Las Cumbres Observatory


    Radial velocity Image via SuperWasp http:// http://www.superwasp.org/exoplanets.htm


    Planet transit. NASA/Ames

    Upon Pi Mensae b’s discovery in 2001, the planet was found to be in a highly eccentric 5.89 Earth-year (2,151 day) orbit – coming as close at 1.21 AU and passing as far as 5.54 AU from its star.

    4
    Artist’s depiction of a Super-Juiter orbiting its host star

    With a 1.21 AU periastron, Pi Mensae b passes through its parent star’s habitable zone before arcing out to apastron (which lies farther out than Jupiter’s orbit of our Sun).

    Given the extreme eccentricity and the fact that the planet passes through the habitable zone during each orbit, it would likely have disrupted the orbit of any potentially Earth-like planet in that zone due to its extreme mass of more than 10 times that of Jupiter.

    As for Pi Mensae itself, the star is a 3.4 billion year old (roughly 730 million years younger than the Sun) yellow dwarf that is 1.11 times the mass of the Sun, 1.15 times the Sun’s radius, and 1.5 times the Sun’s luminosity.

    Due to its proximity to Earth and its high luminosity, the star has an apparent magnitude of 5.67 and is visible to the naked eye in dark, clear skies.

    The star’s brightness – unsurprisingly – gives a potential instant “win” for the TESS team, whose stated pre-mission goal was to find near-Earth transiting exoplanets around exceptionally bright stars.

    Pi Mensae is currently the second brightest star to host a confirmed transiting exoplanet, Pi Mensae b.

    As an even greater testament to TESS’ power, just hours before publication of this article, the TESS team confirmed a second exoplanet candidate from the first observation campaign.

    The second exoplanet candidate is LHS 3844 b. It orbits its parent star – an M dwarf – every 11 hours and is located 49 light years from Earth.

    The exoplanet candidate is described by NASA and the TESS team as a “hot Earth.”

    Given the wealth of light data for scientists to pour through from the now-completed first two of 26 observation sectors, it is highly likely that hundreds if not thousands of exoplanets candidates will be identified in the coming months and years — with tens of thousands of candidate planets to follow in the remaining 24 sectors of sky to be searched.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 7:51 am on September 1, 2018 Permalink | Reply
    Tags: , , , , , Iridium NEXT, NASA Spaceflight   

    From NASA Spaceflight: “Iridium NEXT-8 launch date dependent on satellite manufacturing, availability” 

    NASA Spaceflight

    From NASA Spaceflight

    August 31, 2018
    Chris Gebhardt

    1

    Iridium Communications is nearing the end of its two-year campaign with SpaceX to place 75 Iridium NEXT communication satellites into orbit. The company has launched 65 of those satellites to date, with the final 10 scheduled to launch on a Falcon 9 from Vandenberg Air Force Base, California, before the end of the year.

    The completion of the launch campaign will purposefully leave six NEXT satellites on the ground to serve as launch-replacement spares should they ever be needed over the life of the new constellation.

    Iridium NEXT-8 launch campaign:

    Yesterday, sources confirmed to NASASpaceflight that the Iridium NEXT-8 mission’s launch is now No Earlier Than (NET) November 2018 and that the Iridium NEXT satellites – the mission’s payload – are the cause for the delay, not SpaceX or the Western Range.

    NASASpaceflight’s Chris Gebhardt sat down with Iridium Communications CEO, Matt Desch, to talk about the Iridium NEXT-8 launch campaign.

    “After seven launches, I’m confident now that we’re going to launch this year,” noted Mr Desch. “The issue here is a result of getting basically 12 satellites completed for the 10 that we want to launch. And that looks like it’s going to happen sometime in early to mid-October. That’s still eight weeks from now, when we’ll hit that 12th satellite” being ready for launch.

    The reason for the hiccup in launch processing for this final Iridium mission has to do with a specific and very important part that all of the Iridium NEXT satellites need.

    “It has to do with some parts availability, of a difficult part that is in our satellites.” According to Mr. Desch, the part in question is one that is quite time intensive for the prime contractor – Thales Alenia Space – to build by hand, and getting enough of these parts for all 12 satellites that are part of the Iridium NEXT-8 campaign is the long-pole item to launch.

    “We’re building the satellites without that part and waiting for it to get done and monitoring it very closely” before installing that final part on the satellites, said Mr. Desch.

    Overall, Iridium Communications has 12 satellites for its final launch, though only 10 will be launched. The extra two are best thought of as insurance back-ups. If a primary satellite is found to have an issue just before launch, it can be quickly swapped out with one of the two spares with little impact to the overall launch processing flow.

    2
    Artist depiction of an Iridium NEXT satellite in orbit. Iridium Communications

    Therefore, Iridium NEXT-8’s launch date is right now being driven solely by satellite availability.

    Once Iridium NEXT-8 launches…:

    Once the final batch of 10 satellites is launched later this year, the satellites will all deploy into the same orbital plane and the NEXT constellation’s completion will be imminent.

    “Once they’re up there,” noted Mr. Desch, “we’ll have, quickly, the satellites in position [within a month], and we’ll have a 100% Iridium NEXT network.”

    Having a full NEXT constellation is quite important and something Mr. Desch is looking forward to for a very practical reason.

    “The reason why that’s important isn’t for any services that we have today, it’s for Aireon – which is a live service that will go into operation over the north Atlantic here in 2019. And they need all the time to get the International Civil Aviation Organization certifications and the Air Navigation Service providers to be able to put it into live operations and have controllers use that data,” said Mr. Desch.

    3
    Increased aircraft monitoring is a primary goal. Iridium Communications

    “They’re doing a lot of that today, but they need a 100% network. So [having a full NEXT constellation by the end of this year] will meet their timeline. So, that’s why, at this point, we’re looking to get it done.

    “But there’s nothing driving it having to be done before the end of the year. Mostly I think, in terms of Aireon, I just want to make sure they meet their timeline. But it looks like right now we’ll be completely done here in 2018, and good things happen as a result of that.”

    Completion of the eight-launch campaign will leave nine orbital and six ground spare satellites that can be brought online/launched if needed to maintain the NEXT constellation over the course of its life.

    Interestingly, the number of spares in each location has shifted over the life of the NEXT build and launch campaign.

    “The original plan was to launch 72 satellites. There was going to be eight launches of nine satellites; that was the original plan. Then we moved to seven launches of ten, plus a Dnepr launch, as the first launch,” noted Mr. Desch.

    However, geopolitical considerations ultimately made the Dnepr launch impossible after the Russian government’s invasion and annexation of Crimea in 2014.

    After that, Iridium added an eighth launch with SpaceX and a rideshare for the sixth launch.

    “So we got five satellites on a rideshare. And all in all, it’s funny, the basic amount of money spent on SpaceX has remained the same but we were able to launch, as a result of all that, through an interesting history here, 75 satellites instead of 72.

    “Originally, the plan was to have six orbital spares, one per plane, and nine ground spares, which was kind of an insurance plan. Just in case we had a launch failure, we had nine satellites on the ground.”

    But Iridium – via SpaceX – ended up flipping those numbers to wind up with nine orbital spares and six ground spares.

    “We were able to get nine satellites into space for almost the same cost and have six ground spares, just in case, as sort of a self-insurance plan.”

    With the end of the launch campaign in sight, the six remaining ground spares will be placed into long-term storage with Northrop Grumman and will be stored in a configuration such that they can be launched at any time.

    However, there’s no need for any of the ground or orbital spares right now.

    “We’re currently very confident that the network will work well with the current satellites. [The] nine [orbital spares are] going to be more than enough for a very long time,” said Mr. Desch. “Maybe the complete life of the constellation.”

    4
    Overlapping coverage map. Iridium Communications

    This stems from how Iridium spread out the nine orbital spares.

    “Just with the way we were able to launch and drift them, the nine satellites are going to be distributed very nicely across the planes. We’ll have three planes of two and three planes of one.”

    This was designed so that the planes with two orbital spares are in ideal locations so that one of those two spares can be drifted quickly over into another orbital plane if needed.

    “If we lost a satellite, we could drift another one over into that plane to keep a hot backup. So it turned out very well that the in-flight spares are nicely distributed. And so the need for the ground spares seems unlikely for a long time.”

    Even better for Iridium, satellites actually “store” better in space than they do on the ground.

    To this end, Iridium is not ruling out the possibility of launching the ground spares into orbit to avail themselves of this better storage option.

    “I could imagine in three, four, five years that the right time came and maybe another business opportunity availed itself to us that we would find a good idea that would cost-effectively put [the ground spares] into space for long-term storage.

    “I could see that happening, but there’s not necessarily a need for it,” said Mr. Desch. They could end up staying on the ground forever or we would say that it’s just good to have this sort of backup in space, it’s a better place to put it if we found a cost-effective rideshare or something to do that with.

    “But we’ll see. There’s not an immediate plan to launch them. It’ll be something that we evaluate going forward in a year or two and think about when and where it might make sense to put them into space.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 10:57 am on August 27, 2018 Permalink | Reply
    Tags: "Orion elements coming together for EM-1, Airbus Defence and Space, , , , , ESM-European Service Module, Lockheed Martin, NASA Spaceflight   

    From NASA Spaceflight: “Orion elements coming together for EM-1” 

    NASA Spaceflight

    From NASA Spaceflight

    August 26, 2018
    Philip Sloss

    1

    At a recent media event, NASA’s Orion Program Manager provided a brief update on development and preparations for Exploration Mission-1 (EM-1). Mark Kirasich ran through some of the current status of the EM-1 spacecraft elements that, once assembled and checked out, will make the cislunar test flight currently forecast for mid-2020.

    The three-to-six week EM-1 lunar orbit mission will exercise most of Orion’s systems together for the first time, with the exceptions of a live Launch Abort System (LAS) and Environmental Control and Life Support Systems (ECLSS).

    Preparations for EM-1 are nearing the major milestone of the first European Service Module (ESM) being shipped to the Kennedy Space Center (KSC), but NASA and its contractors still have work to complete with the ESM and the Crew Module (CM) and issues to work out before the first deep-space Orion spacecraft can be put together early next year in Florida.

    Orion EM-1 status

    EM-1 is a first flight for most of NASA’s current human exploration programs.

    2
    SLS/Orion

    Orion will be flying for the first time with a live Service Module, enabling the multi-week flight into a Distant Retrograde Orbit (DRO) around the Moon. The spacecraft will be flying on top of the Space Launch System (SLS) booster’s first flight, which will also be the first launch from Exploration Ground Systems’ rebuilt launch operations infrastructure at KSC.

    NASA, Orion prime contractor Lockheed Martin, and ESM prime contractor Airbus Defence and Space, are nearing the phase of preparations with the major elements of the spacecraft, the CM, the ESM, and the Crew Module Adapter (CMA), mated together. The CMA will first be mated to the ESM, forming most of the overall Service Module (SM), followed by the CM being mated to the SM.

    Both the ESM and CM are getting close, but not there yet. “The crew module and ESA (European Space Agency) service module I would say are greater than ninety-six percent assembled,” Kirasich said during a short break in NASA Administrator Jim Bridenstine’s tour of the Michoud Assembly Facility (MAF) on August 13. “The service module has about three or four components yet to be installed and we’re working a valve issue on the service module.”

    The critical path item driving the EM-1 schedule for Orion is still the first ESM, Flight Model-1 (FM-1); Airbus is working through functional testing of its standalone systems at its Assembly, Integration, and Testing (AIT) facility in Bremen, Germany, along with final pre-ship installations.

    3
    Airbus Defence and Space is in the home stretch of work to ship the first European Service Module (ESM) to its Florida launch site for integration with the rest of the hardware for NASA’s Orion spacecraft. When fully assembled and tested, Orion will be launched on the Exploration Mission-1 (EM-1) test flight to orbit the Moon and return.

    ESM-1 is now undergoing subsystem functional testing at its Assembly, Integration, and Testing (AIT) facility in Bremen, Germany, following completion of most hardware that can be installed on-site. Also known as Flight Model-1 (FM-1), the module will be flown to the Kennedy Space Center this summer to begin the sequence of steps to put together the full Orion spacecraft.

    As FM-1 nears completion, Flight Model-2 (FM-2) has joined its sister module in the clean room at Bremen to begin its AIT flow. NASA and the European Space Agency (ESA) are also working with prime contractor Airbus on beginning construction of ESM hardware for subsequent modules this summer.

    Recently, a nozzle was temporarily installed on the Orbital Maneuvering System-E (OMS-E) main engine at Bremen as a part of functional testing of the Thrust Vector Control (TVC) system.

    4

    “Notwithstanding the valve issue, to get through those last three or four installations we’d be shipping about September 21st,” Kirasich noted. “We’re working feverishly on how do we correct the valve problem, and that could take a day, it could take a week, [or] it might take a little longer. So the valve problem is our toughest problem there.”

    The valve issue was discovered during recent pre-test checkouts of the ESM Propulsion Qualification Module (PQM). “The valves are in the PQM test article and when we were acceptance testing the upgraded PQM was where we first identified the issue,” Kirasich explained. “And then we validated it’s on the flight hardware, too.”

    As Mr. Kirasich noted, the schedule impact to the ESM FM-1 ship date is still to be determined.

    Work in the Operations and Checkout Building at KSC by Lockheed Martin on the CM for EM-1 recently passed a major milestone with installation of the heatshield in late July. Kirasich said that there’s still some work remaining before the CM is ready to mate. “The crew module is the same thing, it’s greater than ninety-six percent done,” he said.

    6

    “With the crew module, really [what’s left is] the side hatch, which we weren’t planning to fly on EM-1. Initially, we were going to do it on EM-2 for the first time, but we had a little extra money. We shook out the sofa cushions a few years ago and it’s been on a fast track and because we started it late it’s been behind. So it will be our last component that shows up.”

    Technicians are also still checking out CM systems. “We’re doing qualification of our components, our avionics boxes, after the flight components were installed,” Kirasich explained.

    “Most of the components are passing qual but [with] a couple of them we identified some issues from qual so we had to pull those boxes, send them back to the factory for refurb, and we’ll get them back in the ensuing couple of months.”

    The CM currently has a little bit more room in its schedule to handle this. “The service module arrives and then it has about two months of work with the crew module adapter — to integrate it, test it — and then we mate with the crew module,” Kirasich noted. “So the crew module still even with these boxes I’m telling you about has got a couple of months of margin.”

    The third major element, the CMA, is the least complex and it has already completed testing. “It’s ready and its avionics boxes are good,” he said.

    PQM testing scheduled to resume in mid-September

    While the flight hardware continues to be processed for mating, Orion still has major parts of its Design, Development, Testing and Evaluation (DDT&E) to complete in parallel with work to transition to more of a “production and operations” phase in flights beyond EM-2.

    The structural test articles (STA) currently at Lockheed Martin are undergoing a series of tests in the different combinations they will see during flight. Those tests will continue into 2019.

    5

    At the White Sands Test Facility in New Mexico, the PQM is being checked out to resume testing next month. “We’re targeting September 12th,” Kirasich said. “We had to make about three major changes and a half dozen minor changes to the test article to make sure we don’t have that phenomenon again.”

    One of the PQM’s RCS thrusters had a failure during an initial round of “blowdown” testing in August of last year. “We did blowdown testing because we didn’t have our pressure controller that regulates the pressures to the gas tanks,” Kirasich explained.

    “We would pressurize the tanks and then we would burn, but you can’t burn very long that way. So we got the pressure controllers installed now [and] we’re about one month out.”

    EM-3 hardware ordered

    Kirasich was at MAF in New Orleans as a part of Administrator Bridenstine’s visit, which coincided with the completion of the pressure vessel for the EM-2 CM. Mr. Bridenstine was sworn in as NASA Administrator in late April and is currently making time to tour all of NASA’s centers and facilities.

    Several of the items that Lockheed Martin processes at MAF were on display for the Administrator and for media observing the tour. The spacecraft adapter cone, a Spacecraft Adapter Jettisoned (SAJ) panel and a LAS ogive panel for EM-1 surrounded the EM-2 pressure vessel.

    In the back of the area, the primary Launch Abort System (LAS) structure for the Ascent Abort-2 (AA-2) was also visible as it is being processed for the test schedule for next April.

    Long term Orion program planning and production also continues, and Kirasich confirmed that long-lead orders for the EM-3 vehicle were made earlier this year. “Over the last four to five months we’ve started ordering EM-3 raw materials, the aluminum plates that will become the crew module,” he said. “Those will get delivered over the ensuing months and the process starts again. So we are into EM-3.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: