From NASA Spaceflight: “Unpacking the proposed exo-planet imaging telescope HabEx”

NASA Spaceflight

From NASA Spaceflight

September 19, 2019
Roland Winkler

NASA Habitable Exoplanet Imaging Mission (HabEx) The Planet Hunter depiction

1

As part of NASA’s continued effort to ensure a steady supply of astrophysics and astronomy missions, the agency is undertaking the Astro2020: Decadal Survey on Astronomy and Astrophysics. Currently, in the “Concept Study” phase, the survey includes proposals for four large-scale space telescopes – including the Habitable Exoplanet Observatory (HabEx).

HabEx would facilitate direct observation of exoplanets, carry a primary focus on imaging Earth-like planets around Sun-like stars, and be able to detect biomarkers or signs of possible life in those exoplanets’ atmospheres via spectroscopic observations.

HabEx – taking exoplanet research to the next level:

For millennia, the question of whether or not humanity is alone in the universe has captivated the minds of explorers and scientists.

But until recently, an important part of that equation remained elusive: exactly how many exoplanets exist in our galaxy and the universe?

The first confirmed detection of an exoplanet occurred in the early 1990s, with subsequent observations confirming the earliest detection actually occurred in the 1980s. But ground-based observations were slow and far between.

To help solve the question once and for all, NASA launched the Kepler Space Telescope in 2009 – a telescope tasked solely with searching for exoplanets and determining how common they are.

NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018

Kepler shattered all expectations of the number of exoplanets near Earth, revealing over the course of its multi-year mission that not only are exoplanets common throughout all regions within the visible space surrounding Earth but that almost every single star hosts at least one planet.

What’s more, Kepler revealed an astonishing number of exoplanets that orbit within the so-called habitable zone of their parent stars – the zone in which liquid water can exist on the surface of a terrestrial planet.

As of 1 September 2019, there are 4,109 confirmed exoplanets in 3,059 systems, with 667 systems having more than one planet.

With that discovery, the desire to create better telescopes capable of directly imaging exoplanets and sampling their atmospheres catapulted to the top of the astrophysics mission wish lists.

But so far only very large planets, many times larger than Jupiter and far away from their host stars have been imaged directly. Spectroscopic observations of exoplanet atmospheres are possible using telescopes and technology is possible but rare and very limited. The holy grail of directly imaging Earth-like planets around Sun-like stars is currently not possible.

Thus, the holy grail of directly imaging Earth-like planets around Sun-like stars is currently not possible.

3
HabEx with its starshade performing operations NASA/JPLK-Caltech

Enter HabEx. This proposed mission carries the stated goals of:

Seeking out nearby worlds and exploring their habitability
Mapping out nearby planetary systems and understanding the diversity of the worlds they contain, and
Enabling new explorations of astrophysical systems from our solar system to galaxies and the universe by extending our reach in the ultraviolet, optical, and near-infrared spectrum.

How will HabEx work?

When directly observing exoplanets, the biggest problem to overcome is the glare of the host star, which is billions of times brighter than the exoplanet.

Two of HabEx’s four instruments are designed to do exactly that.

The first instrument is a star shade, which is actually a second spacecraft that would fly in formation at an average distance of 124,000 km in front of HabEx and block most of the host star’s light but not the light of planets in orbit of the host star.

A dedicated instrument on HabEx would then pick up the light of these exoplanets and measure their spectrum.

With enough observation time, HabEx’s instruments would be able to measure the concentration of water vapor, oxygen, ozone, and dust through Rayleigh scattering.


SETI Institute “Next-Generation NASA Space Telescopes” 1:13:30

The telescope would also be able to detect carbon dioxide and methane in an exoplanet’s atmosphere if they were present in higher concentrations than on Earth.

The observation campaign would theoretically involve nine nearby solar systems at a distance of 10 to 20 light years.

They would be observed three times each with an accumulated observation time of three months within the first five years of the telescope’s operation.

Due to the nature of formation flying, pointing the star shade on a different target would be a slow, time-consuming process. Therefore, during times when the star shade would be repositioned on another star system, HabEx would use its other instruments, including a vector vortex coronagraph, to create family portraits of around 110 exosolar systems.

The coronagraph, a telescopic attachment designed to block out the direct light from a star so that nearby objects – which otherwise would be hidden in the star’s bright glare – can be resolved, would block the light of the host star but not the light of the exoplanets in the system.

Within the first 5 years, the coronagraph would be used for 3.5 years to create family images of 110 exosolar systems and detect dust, asteroid belts, and Kuiper Belt-like regions of exosolar systems. From these observed star systems, the ones with rocky planets in their respective habitable zones would be scheduled with star shade observations.

4
Exoplanet observation with HaBEx and its star shade. NASA/JPL-Caltech

Together, the star shade and coronagraph would take about 75% of the first 5 years of observation time. The remaining 25% would be dedicated to the scientific community, which would submit observation proposals via a similar selection process as used today for the Hubble Space Telescope.

In addition to the coronagraph and star shade, HabEx is proposed to contain two other important instruments: the HabEx Workhorse Camera (HWC) and the UV Spectrograph (UVS).

The UVS intended for HabEx would provide 10 times larger area coverage compared to Hubble’s equivalent: the Cosmic Origins Spectrograph. With the Hubble Space Telescope close to the end of its life, the astronomic community will lose its only UV spectrograph with HST. UVS would fill that gap.

Additionally, HabEx’s Workhorse Camera (HWC) would be an evolutionary step from Hubble’s Wide-Field Camera 3 and would provide imaging and multi-slit spectroscopy for two channels ranging from the near UV to the near IR.

When executing exoplanet observations, both HWC and UVS could also be used in parallel with the star shade and coronagraph.

What’s in a star shade?:

The star shade for the HabEx Observatory would have a diameter of 72 m, consists of several thin sheets of material, and would be scaled relative to its operational distance from HabEx so that the telescope would be able to observe Earth-like planets around sun-like stars at a distance between 10 and 20 light years.

4
A breakdown of HabEX. NASA/JPL-Caltech

It would have a 40 m diameter disk and 24 petals, each 16 m long and 5.25 m wide at its base for a structure tip-to-tip of 72 m. The total mass of the star shade is currently estimated at 2,520 kg with an additional 500 kg for the deployment mechanism.

The material used to create the shade would be made of multiple layers of carbon-impregnated black Kapton. A gap between the individual layers would minimize the risk of a micrometeorite hit inducing a direct line of sight path between the target star and the telescope.

The edges of each petal would also be chemically etched to produce a very sharp and smooth edge that minimizes light scattering.

The star shade would be attached to its control hub, which is currently projected to weigh in at 6,394 kg.

The hub would consist of propellant and control systems, including 12 hydrazine thrusters for station keeping with HabEx. These thrusters would use 1,407 kg of liquid bipropellant.

Additionally, the hub would be equipped with six xenon Solar Electric Propulsion (SEP) thrusters for retargeting. This would require 5,600 kg of xenon gas.

The amount of propellant planned would be enough for 100 individual pointings with an initial mission design of 18 pointings for the first 5 years.

Using a coronagraph on HabEx:

Coronagraphs are already in use for solar observations as well as in various ground-based telescopes and upcoming space missions such as the James Webb Space Telescope (JWST) and WFIRST.

NASA/ESA/CSA Webb Telescope annotated

NASA/WFIRST

Like these telescopes, HabEx’s coronagraph could only work well if the light path through the telescope is extremely stable and matches its design exactly. Any deformation due to thermal gradients, vibration in the spacecraft, polarization, and other effects would diminish its functionality.

The quality of optical surfaces must also be very high, which is why the coronagraph is the design driving element for many aspects of the HabEx telescope.

To limit the vibration of HabEx, the telescope would not employ reaction wheels for pointing. Instead, microthrusters would be used, as demonstrated by NASA’s Gravity Probe B and ESA’s (European Space Agency’s) Gaia and LISA Pathfinder missions.

The microthrusters would induce far less vibration to the system and would not be prone to failures as reaction wheels are.

To limit the thermal stress on the primary mirror, the instruments are housed on the side of the telescope.

6
Images: Hubble left, HabEX right

The diameter of HabEx main mirror is proposed at 4 m and designed to be made of 0-expansion glass ZERODUR, which would be heavier than other options but can be handled by the usual manufacturers without major hassle contrary to the Beryllium mirrors of JWST.

Moreover, the coronagraph would drive the focal length of the optical design (i.e.: the length of the telescope) to a long telescope.

How to launch HabEx:

Should HabEx be approved as a mission, the immediate question would become how to launch it.

In all, an integrated launch of HabEx and its star shade would place the launch mass at a little less than 35,000 kg with the launch needing to inject HabEx into the Earth-Sun L2 Lagrangian Point 1.5 million km from Earth.

In short, there aren’t many options.

NASA’s SLS Block 1B would be capable of launching the telescope. SpaceX’s Starship vehicle, while still in development with fluid performance numbers, is in a similar class as SLS 1B, and is thus another potential option

However, neither of those rockets exist operationally at this point, and even when/if they do, there are questions as to what they will ultimately be capable of doing.

8
SLS’s Block 1B future is precarious at best with an unknown funding situation of the crucial Exploration Upper Stage – which has already been delayed multiple years and has forced NASA to switch several early SLS missions to the Block 1 configuration – as well as an “at any cost” lunar landing objective by 2024 for which the Block 1B is in no way required and would divert funds and attention away from.

If SLS Block 1B does come to fruition and is used to launch HabEx, the telescope would benefit from the rocket’s capacity to throw more than 36,000 kg to the Earth-Sun L2 point.

The Earth-Sun L2 point would be the primary operation location for HabEx given the area’s flat gravitational gradient and an undisturbed thermal environment.

It would also allow for relatively easy servicing of HabEx as now mandated by the U.S. Congress in 2010 that all large spacecraft be serviceable.

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.

#unpacking-the-proposed-exo-planet-imaging-telescope-habex, #astronomy, #astrophysics, #basic-research, #cosmology, #exoplanet-hunting, #nasa-kepler-and-k2, #nasa-spaceflight

From NASA Spaceflight: “Russia pressing forward on ISS expansion”

NASA Spaceflight

From NASA Spaceflight

July 3, 2019
Ian Atkinson

1

Russia is working towards the future expansion of its segment of the International Space Station. Although major additions to the United States’ segment have mostly ceased following the end of the Space Shuttle Program in 2011, Russian segment expansion is set to restart as early as the middle of next year.

Russian segment expansion

Since the International Space Station (ISS) program started in the 1990s, Russia has intended to expand its segment of the ISS from its current configuration. The first proposed module was the Science Power Platform – also known as the NEP – designed for the canceled Mir 2 space station.

The NEP would have consisted of two parts – a small pressurized module, and a truss with solar arrays, radiators and a robotic arm. The eight solar arrays would have generated enough power to end the Russian segment’s partial-reliance on the United States segment’s solar arrays.

2
NEP

However, the NEP was cancelled in 2004 after a lack of funding. In the same year, the focus was switched from the NEP to a new module, Nauka.

Nauka – also known as the Multipurpose Laboratory Module, or MLM – was to be built from the unfinished backup for the existing Zarya module, Functional Cargo Block 2. It would be the main Russian science and research module, with additional living quarters for cosmonauts.

Nauka would feature solar arrays, radiators, and the robotic arm designed for the NEP. Spare parts for Nauka were launched to the ISS in 2010 on the Rassvet module.

3
Nauka docked to the underside of the Zvezda module-NASA

The launch date for Nauka has been plagued with delays, often related to its propulsion system. In 2013, a leaking valve was discovered, necessitating the valve’s replacement and a thorough decontamination of the module.
In 2014, it was discovered that most of the exterior plumbing on Nauka needed to be replaced because of the propellant leak. In addition, the warranty on the module’s engines had expired, requiring them to be replaced.

In 2017, metallic dust was discovered inside Nauka’s propellant tanks. After trying out repair techniques on a test article tank, it was decided to replace the contaminated tanks altogether with single-use tanks derived from those on the Fregat upper stage.

Current ISS planning schedules show Nauka’s launch date as June 2020. However, that is likely to be pushed back further due to the fuel tank replacement.

After Nauka, the second new Russian module will be the Prichal node – previously known as the Uzlovoy module. Prichal is a spherical docking node featuring six docking ports – one of which will be attached to the underside of Nauka.

3
Prichal will allow additional Soyuz and Progress spacecraft to dock to the station, along with future station modules.

Prichal is scheduled to launch on a modified Progress spacecraft in December 2020. However, that is dependent on when Nauka launches.

The third new Russian module is the Science-Power Module-1 – also known as SPM-1 or NEM-1.

Russia began designing two NEM’s following the cancellation of the NEP, with the NEM’s taking on many of the NEP’s responsibilities. Since the NEM’s would be clean-sheet designs, they were able to feature more modern systems.

Currently, only one NEM has been funded and scheduled for launch, designated NEM-1.

4
The design of NEM-1 is somewhat similar to that of the NEP. The module is made up of a pressurized section – although much larger than that of the NEP – and an unpressurized section.

he pressurized section features crew quarters, medical equipment, life support systems, and payload racks. The unpressurized section contains large solar panels, a satellite communication antenna, radiators, and external payload mounts.

The module will contain a universal payload rack system, similar to the one used in the modules of United States’ segment. This will allow medical, scientific, fitness, and crew quarters racks to be easily interchanged.

A mockup of the module’s interior was built in 2014 to demonstrate the new rack system. It is now being used to train astronauts and simulate crew activities.

RSC Energia – in charge of developing the three new Russian modules – finished testing on a test article of NEM-1’s pressurized section on June 25, 2018. A test article of the unpressurized section finished testing in February 2019.

The tests were a success, confirming that the module will survive for its rated 15-year lifespan. The two test articles will later be converted into simulators for use in a neutral buoyancy lab.

5
NEM-1 undergoing structural tests.

According to a recent ISS planning schedule, NEM-1 will launch and dock to Prichal in June 2021 – although many sources are pointing to a 2022 launch date. NEM-1 will launch on a Proton rocket and dock itself to the ISS.

Due to the module’s large size, it will require a custom-made fairing to be able to fit onto a Proton. The fairing will be made up of two parts – a lower cylindrical portion to cover NEM-1’s unpressurized section, and a conical section to cover the top docking port.

The side of the pressurized section will be left uncovered. Wind tunnel testing was performed on a model of the fairing in 2014.

After NEM-1 is attached to the ISS, expansion of the Russian section will be complete. In the past, Russia planned to detach their segment and turn it into an independent space station, called OPSEK. However, they confirmed in 2017 that they were no longer considering this option.

6

Altogether, the three new modules will increase the Russian segment’s internal volume by approximately 60 percent. Nauka and NEM-1 will significantly expand the power generation of the Russian segment, ending its reliance on additional power from the United States’ segment.

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.

#nasa-spaceflight, #nauka-also-known-as-the-multipurpose-laboratory-module-or-mlm, #nep-science-power-platform, #prichal-will-allow-additional-soyuz-and-progress-spacecraft-to-dock-to-the-station-along-with-future-station-modules, #russia-pressing-forward-on-iss-expansion, #science-power-module-1

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.

#dream-chaser-progress-ahead-of-crs2-as-snc-keeps-crew-version-alive, #nasa-spaceflight

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.

#nasa-spaceflight, #ng-10-cygnus-departs-iss-after-3-month-science-supply-mission, #northrop-grumman-controllers-will-fire-cygnus-engine-to-raise-the-crafts-orbital-altitude-above-that-of-the-stations-in-this-higher-orbit-cygnus-will-deploy-two-cubesats-fo

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.

#astronomy, #astrophysics, #basic-research, #cosmology, #nasa-spaceflight, #nasaesaasi-cassini-huygens-spacecraft, #saturn-and-its-rings-and-dust

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.

#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: “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.

#astronomy, #astrophysics, #basic-research, #cosmology, #crewed-orion-spacecraft-passes-critical-design-review, #nasa-spaceflight