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  • richardmitnick 10:46 pm on November 11, 2021 Permalink | Reply
    Tags: "Mind-blowing pictures of the solar system's most volcanic worlds", The Planetary Society   

    From The Planetary Society: “Mind-blowing pictures of the solar system’s most volcanic worlds” 

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    From The Planetary Society

    Nov 11, 2021
    Rae Paoletta

    Over the last several millennia, volcanoes racked up some ill will here on Earth. It’s really more of a PR problem, since most of the time volcanoes are in the news it’s about towns and cities they’re leveling. History hasn’t exactly been kind to volcanoes either, especially the ones — ahem, Vesuvius — that sabotage civilizations.

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    Mount Vesuvius from Naples with sunset lighting. Credit: Massimo Finizio.

    Volcanoes are undeniably destructive. But it might be fairer to view volcanoes as harbingers of change, since volcanoes also sculpt geographical features and enrich the soil that gives rise to new life. That’s just on Earth, though — we’re lucky enough to have volcanoes scattered all across the solar system, some of which are wildly different than what we’re used to.

    So, having said all this: where are the space volcanoes? Here are some scientists have spotted and others that seem to be suspects.

    Io
    Verdict: Volcano world for sure.

    Jupiter’s mercurial moon Io is widely considered the most active volcanic moon in the solar system. Some — including NASA — say it’s the most volcanically active world we know of.

    “The largest and most powerful volcano on Io is Loki,” said Julie Rathbun, a senior scientist at the Planetary Science Institute in Tucson, Arizona studying Io’s volcanoes. “It’s a giant lava lake — yes, a lake of liquid magma — about 200 kilometers (about 125 miles) across. Not only is Loki huge and puts out a ton of energy, but it also often behaves in a predictable way, erupting on schedule approximately every 500 days.”

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    Io, a world of constant chaos NASA has called Io the “most volcanic body in the solar system.”Image: JPL/Caltech-NASA (US)/The University of Arizona (US).

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    Eruption at Tvashtar Catena, Io. The Galileo spacecraft caught Io in the act of an active volcanic eruption on Februrary 22, 2000.

    National Aeronautics and Space Administration(US) Galileo 1989-2003.

    Tvashtar Catena is a chain of calderas, collapse pits formed by volcanic eruptions. The active site of the eruption is visible on the left edge of the image, where infrared imaging sees the glow of a hot lava flow more than 60 kilometers long.Image: NASA / JPL.

    Loki is one of the hundreds of volcanoes that cover Io’s surface. Jupiter’s other Galilean moons — Europa, Ganymede and Callisto — don’t show anywhere near this level of activity, so why does Io have so many volcanoes?

    “Because of the way Io and the other Galilean Satellites orbit Jupiter, Jupiter is constantly squeezing Io in every orbit,” Rathbun said. “All of this squeezing — a process called Tidal Heating — heats up Io’s interior and that heat is released at the surface as volcanoes.”

    Venus
    Verdict: Yeah, it’s got volcanoes, but it’s complicated.

    There’s a lot that can be said about Venus, but at least it’s not boring. The hostile world may or may not have hosted life; however, it’s definitely home to many volcanoes. In fact, Venus may have the most volcanoes of any planet in the solar system.

    “Theia Mons is the largest volcano on Venus, rising to a height of about 4 kilometers (about 2.5 miles) above the surrounding plains but with a lateral extent of almost 800 kilometers (about 500 miles),” said Paul Byrne, a planetary geologist at The North Carolina State University (US). “It’s a monster, though it’s not the tallest volcano on Venus, which is Maat Mons. Both are huge shield volcanoes, of the same type as the Hawaiian islands on Earth, say, or the Tharsis Montes and Olympus Mons on Mars.”

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    Venus’s surface from radar data This 3D image of Venus’ surface was generated using radar data from NASA’s Magellan spacecraft.

    NASA/Magellan spacecraft mission to Venus, May 4, 1989-Oct. 13, 1994.

    The 3-kilometer-tall volcano Gula Mons can be seen on the horizon, along with the 48-kilometer-wide Cunitz crater at near-center.Image: NASA.

    While we know Venus is full of volcanoes, we don’t know how many active volcanoes there are — if any. Recent research suggests there may be at least 37 active volcanoes on the greenhouse world, but scientists have yet to directly image them. Hopefully, upcoming missions to Venus — including VERITAS, EnVision and DAVINCI+ — will provide more evidence for active volcanism on the planet.

    Though Venus is literally and figuratively shrouded in mystery, one thing’s for sure: just like on Earth, Venus’ volcanoes have sculpted the surface. Their hand in molding the geography is part of what makes the planet so distinct.

    “One of the most striking things about Venus is the relative lack of large impact craters and basins, and we think the reason for this dearth is volcanic resurfacing,” Byrne said.

    Europa
    Verdict: Well…

    Not to get too philosophical here, but Europa begs the question: what even is a volcano? If we’re using the most basic definition — a surface opening where something like lava and/or gases escape — then yeah, you could say Europa shows signs of volcanic activity. Kind of.

    “There’s some evidence that Europa is volcanically active, though this in part depends on what you consider ‘volcanic activity,'” Byrne said. “Remote observations of Europa with, for example, the Hubble Space Telescope has found evidence for plumes at the moon’s surface, like a fainter version of those we see at Saturn’s moon Enceladus. But it’s not the kind of activity we associate with the inner planets or another of Jupiter’s moon, Io, for example.”

    The wildcard with Europa is whether it has a) a subsurface ocean beneath its icy crust, and b) a core hot enough to help create seafloor volcanoes. New research says it may be possible, but for direct insights, we’ll have to wait for Europa Clipper to reach the Jovian moon in 2030.

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    Europa. NASA’s Voyager 2 spacecraft captured the images used to make this high-resolution mosaic of Europa in 1979.

    National Aeronautics and Space Administration(US)Voyager 2.

    The mosaic has been rotated 90 degrees clockwise from its original orientation.Image: NASA/Ted Stryk/Edited by The Planetary Society.

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    Volcanoes of our solar system The solar system is home to some truly impressive volcanoes. Image: The Planetary Society.

    Triton
    Verdict: Yes. Also, is there anything cooler than ice volcanoes in space?

    Though it sounds like something from sci-fi, Neptune’s mysterious moon Triton really does have cryovolcanoes, also known as ice volcanoes. These kinds of volcanoes are found on icy worlds and release volatiles like water and methane rather than molten rock.

    “The cryovolcanic activity on Triton is mostly by basins infilled with viscous cryolava, plus active geysers,” said Caitlin Ahrens, NASA postdoc at The Goddard Space Flight Center-NASA (US) who’s contributed to several books on space volcanoes. “The geysers are still under debate as to how they work — they are either endogenic (pressurized, tidally bits of nitrogen from the subsurface) or exogenic (sublimation erosional process to expose the nitrogen pockets to spurt).”

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    Neptune’s moon Triton Voyager 2 acquired the images for this high-resolution mosaic of Triton on 25 August 1989. Visible in the south are dark splotches formed by nitrogen geysers that could be linked to a subsurface ocean.Image: Ted Stryk/NASA/JPL.

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    Best View of Triton Voyager 2’s highest resolution view of Triton, taken during its Neptune flyby in 1989. Image: NASA/JPL.

    Only one spacecraft — Voyager 2 — has ever visited Triton. In 1989, the spacecraft took pictures of volcanic plumes coming from the moon. But there haven’t been any missions to Triton since then, so there’s still a lot we don’t know about the far-flung world and its ice volcanoes. Hopefully that changes someday soon.

    Enceladus
    Verdict: Not your typical “volcano world,” but it definitely has active ice geysers — lots of them.

    There’s so much to love about Enceladus. In addition to being a location of interest in the search for life, the Saturnian moon appears to have a subsurface ocean and active geysers in its south pole. NASA’s Cassini spacecraft flew through and sampled these geyser-like plumes several times, the results of which are still being analyzed by scientists around the world.

    National Aeronautics and Space Administration(US)/European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU)/ASI Italian Space Agency [Agenzia Spaziale Italiana](IT) Cassini Spacecraft.

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    Enceladus in view This false-color image was assembled using infrared, green, and ultraviolet filtered images (IR3/GRN/UV3). Image: Kevin M. Gill/ NASA/JPL-Caltech / Space Science Institute.

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    Enceladus’ plumes in cross-eyed stereo Cassini swept past Enceladus’ south pole for one last close look before winter darkness swallowed the enigmatic tiger stripe terrain and gathered these dramatic shots of plumes issuing from south polar vents.Image: NASA / JPL-Caltech / SSI / stereo comparison by Gordan Ugarkovic.

    Enceladus’ geysers are likely linked to the “tiger stripes” that decorate the world’s southern hemisphere. Some research shows that more than 100 geysers can be found along these regions of fractured terrain; it’s possible that Saturn’s gravitational pull on Enceladus causes it to compress and stretch, putting stress on the tiger stripe regions and influencing the geysers within them.

    Earth
    Verdict: C’mon. We all know it’s a volcano world.

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    Cumbre Vieja erupts Plumes trail from the 2021 Cumbre Vieja eruption in La Palma, Canary Islands.Image: The NASA Earth Observatory (US)..

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    Mount Redoubt, Alaska. The volcano is seen here erupting in 2009.Image: NASA.

    So why is our planet so rich in volcanoes compared to other places in our solar neighborhood?

    “Earth has the magic of plate tectonics and an active mantle,” said Ahrens. “Other worlds have active — or sometimes partially active — mantles, but their crusts would break or bend or move as one big ‘shell,’ and not puzzle pieces like Earth’s.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    3

    In 1980, Carl Sagan, Louis Friedman, and Bruce Murray founded The Planetary Society. They saw that there was enormous public interest in space, but that this was not reflected in government, as NASA’s budget was cut again and again.

    Today, The Planetary Society continues this work, as the world’s largest and most influential non-profit space organization. The organization is supported by over 50,000 members in over 100 countries, and by hundreds of volunteers around the world.

    Our mission is to empower the world’s citizens to advance space science and exploration. We advocate for space and planetary science funding in government, inspire and educate people around the world, and develop and fund groundbreaking space science and technology.

    We introduce people to the wonders of the cosmos, bridging the gap between the scientific community and the general public to inspire and educate people from all walks of life.

    We give every citizen of the planet the opportunity to make their voices heard in government and effect real change in support of space exploration.

    And we bring ordinary people directly to the frontier of exploration as we crowdfund innovative and exciting space technologies.

     
  • richardmitnick 8:30 am on December 1, 2020 Permalink | Reply
    Tags: "Comet 2019 LD2 (ATLAS) Found To Be Actively Transitioning", , , , , The Planetary Society   

    From The Planetary Society: “Comet 2019 LD2 (ATLAS) Found To Be Actively Transitioning” 

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    From From The Planetary Society

    Nov. 27, 2020

    MEDIA CONTACT:
    Alan Fischer
    Public Information Officer
    520-382-0411
    fischer@psi.edu

    SCIENCE CONTACT:
    Jordan Steckloff
    Research Scientist
    jsteckloff@psi.edu

    1
    Comet 2019 LD2 (ATLAS) as seen by the Hubble Space Telescope. Credit: NASA/ESA Hubble/Bryce Bolin.

    A comet discovered last year is offering scientists new insights into how these objects “turn on” and evolve, as it actually transitions out of the Centaur population and into the Jupiter Family of Comets (JFCs), according to a paper by Planetary Science Institute Research Scientist Jordan Steckloff.

    “The newly discovered comet 2019 LD2 (ATLAS) is a Centaur, but is actively transitioning into a JFC. It is in the very earliest parts of this transition, and is the first time an object has been discovered prior to embarking on this transition,” said Steckloff, lead author of the paper “P/2019 LD2 (ATLAS): An Active Centaur in Imminent Transition to the Jupiter Family” in The Astrophysical Journal Letters.

    Centaurs are icy bodies in unstable orbits between Jupiter and Neptune, and cross the orbits of one or more of the giant planets in their journey around the Sun; the gravity of these planets provide rapid dynamical evolution of the objects, and either eject them from the solar system entirely, or cause them to eventually evolve inward of Jupiter, to become Jupiter Family Comets. Prior to this migration, Centaurs began as objects beyond the orbit of Neptune (trans-Neptunian Objects), whose gravitational tugs causes object to slowly leak into the Centaur population; this entire migration from beyond Neptune to JFC lasts a few million to a few tens of millions of years.

    “We find that 2019 LD2 is currently in the vicinity of a dynamical ‘Gateway’ that facilitates the majority of transitions from the Centaur population into the Jupiter Family of Comets. The dynamical gateway is a region beyond Jupiter, extending to just inside of Saturn’s influence,” Steckloff said. “Our previous work (Sarid et al. 2019) found that the majority of JFCs first pass through this dynamical gateway as Centaurs immediately prior to transitioning into the JFC population; indeed this ‘Gateway Region’ facilitates the majority of transitions between the JFC and Centaur populations. Currently, there are a handful of objects in the gateway, including LD2, and the much more famous object 29P/Schwassmann-Wachmann 1.

    “Most significantly, our work found that LD2 is most likely a pristine comet. Although it has likely lost some supervolatile ices such as carbon dioxide ice (also known as dry ice) in the Outer Solar System beyond Jupiter, it is unlikely to have ever been in the inner Solar System (where Earth, the other rocky planets, and JFCs orbit), which is warm enough for water ice to sublime (‘evaporate’ from solid to gas),” Steckloff said. “This means that LD2 is a pristine comet, and presents a unique opportunity to observe how pristine JFCs behave as their water ice begins to sublime for the first time and drive comet activity. Moreover, this transition is likely to finish in only 40 years from now, which is a blink of an eye for astronomy. This means that people alive today will be able to follow this object all the way through its transition into the JFC population.”

    Steckloff said that scientists like to categorize things and put them into well-defined boxes. Part of modern planetary science is about understating why these categories exist in the first place (for example, we have active comets, inactive asteroids), and why some objects seem to fit in multiple boxes (Centaurs and Main Belt comets can look both asteroidal sometimes and cometary other times).

    “Crucial to understanding how these categories of objects came about is understanding the processes that they experience, and how they have evolved over time to become the objects that we see today,” Steckloff said. “LD2 represents a unique opportunity to investigate the connection between the JFC and Centaur boxes; to understand how they are different and how they are similar. It presents us with a chance, during our lifetime, to understand how a Centaur physically transforms into a JFC, rather than just dynamically.”

    Steckloff’s work was funded by grants to PSI from the National Science Foundation Astronomy and Astrophysics research grants program (NSF grant 1910275) and NASA’s Emerging Worlds program (NASA award 80NSSC18K0497).

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    3

    In 1980, Carl Sagan, Louis Friedman, and Bruce Murray founded The Planetary Society. They saw that there was enormous public interest in space, but that this was not reflected in government, as NASA’s budget was cut again and again.

    Today, The Planetary Societycontinues this work, under the leadership of CEO Bill Nye, as the world’s largest and most influential non-profit space organization. The organization is supported by over 50,000 members in over 100 countries, and by hundreds of volunteers around the world.

    Our mission is to empower the world’s citizens to advance space science and exploration. We advocate for space and planetary science funding in government, inspire and educate people around the world, and develop and fund groundbreaking space science and technology.

    We introduce people to the wonders of the cosmos, bridging the gap between the scientific community and the general public to inspire and educate people from all walks of life.

    We give every citizen of the planet the opportunity to make their voices heard in government and effect real change in support of space exploration.

    And we bring ordinary people directly to the frontier of exploration as we crowdfund innovative and exciting space technologies.

     
  • richardmitnick 12:52 pm on January 10, 2020 Permalink | Reply
    Tags: "Here's What We've Learned So Far from LightSail 2", The Planetary Society   

    From The Planetary Society: “Here’s What We’ve Learned So Far from LightSail 2” 

    1

    From From The Planetary Society

    January 10, 2020
    Jason Davis

    High above Earth, The Planetary Society’s LightSail 2 spacecraft is still sailing on sunbeams. During the 5 months since LightSail 2 deployed its solar sail on 23 July 2019, the spacecraft has continued to demonstrate the first controlled solar-sailing flight in Earth orbit.

    The LightSail 2 team is releasing a paper today that describes new results from the mission. Purdue University’s Justin Mansell is also presenting the results at the 30th Space Flight Mechanics Meeting in Orlando, Florida. The paper recaps mission events through late November, discusses the performance of the solar sail and attitude control system, and describes how the spacecraft’s orbit has changed.

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    LightSail 2 captured this image of the Gulf of Oman and the Persian Gulf on 14 December 2019. The sail appears slightly curved due to the spacecraft’s 185-degree fisheye camera lens. The image has been color corrected and some of the distortion has been removed. The Planetary Society

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    LightSail is a citizen-funded project from The Planetary Society to send a small spacecraft, propelled solely by sunlight, to Earth orbit.

    Earth’s atmosphere is a drag

    LightSail 2 flies at a higher altitude than most satellites in low-Earth orbit. While the International Space Station orbits Earth at an altitude of about 400 kilometers, LightSail 2 orbits at about 720 kilometers. Since fewer spacecraft orbit at LightSail 2’s altitude, there wasn’t enough data on Earth’s atmospheric density to reliably predict how much atmospheric drag would slow down the spacecraft. We now know for certain that the atmosphere at 720 kilometers is dense enough to overcome the thrust imparted by solar sailing.

    The team uses a simple on-off sail control strategy each orbit, turning the sail edge-on to the Sun’s rays when the spacecraft is traveling toward the Sun, and face-on to the Sun when moving away from it. Out of each 100-minute orbit, LightSail 2 spends 67 minutes either in eclipse or moving toward the Sun. Of the remaining 33 “sail-able” minutes each orbit, the spacecraft spends about 5 minutes turning to the desired orientation. Therefore, LightSail 2 enjoys at most 28 minutes of each orbit in an orientation for capturing the momentum of solar photons to change its velocity.

    Mansell and his colleagues documented LightSail 2’s orbital change during time intervals in which it was actively orienting itself for solar sailing and compared that change to periods in which the orientation was not controlled. When the spacecraft was randomly oriented, its semimajor axis—a measure of the size of the orbit—shrank by an average of 34.5 meters per day. When it was solar sailing, the orbit only shrank by an average of 19.9 meters per day. Yet, the rate is highly variable and the semimajor axis actually increased by as many as 7.5 meters some days when sailing, which means LightSail 2 increased its orbital energy during those periods.


    LightSail 2 Sample Orbit Animation
    This video shows LightSail 2’s orientation with respect to the Sun during a single orbit on 24 September 2019. Gaps between data points have been interpolated. The red line shows the direction of the Sun, and the blue line shows the direction of the local magnetic field. When the sailing command is “feather,” LightSail 2 attempts to turn its sail edge-on to the solar photons, meaning the red arrow should be roughly parallel with the sail. (The Sun to -z angle should be roughly 90 degrees.) When the sailing command is “thrust,” LightSail 2 tries to turn its sail broadside to the solar photons, meaning the red arrow should roughly make a 90-degree angle with the sail. (The Sun to -z angle should be roughly 0 degrees.) For more, see https://www.planetary.org/blogs/jason-davis/heres-what-we-learned-so-far-ls2.html. Video credit: Justin Mansell, Purdue University

    The increases in orbital energy from solar sailing are generally not enough to overcome atmospheric drag, so LightSail 2’s orbit is gradually decaying. Pre-launch orbital models predicted that the spacecraft would reenter Earth’s atmosphere and burn up about a year after sail deployment. But since there are few prior examples of spacecraft like LightSail 2 having high area-to-mass ratio, the actual timeline will provide new information about orbital decay rates.

    Future solar sails will be used in higher Earth orbits, or on interplanetary trajectories. NASA’s NEA Scout will ride a Space Launch System rocket out near the Moon and then use solar sailing to visit an asteroid. The LightSail 2 team is sharing data and expertise with the NEA Scout team.

    The ups and downs of LightSail 2’s orbit

    If you’ve looked at our mission control page over the past few months, you may have noticed LightSail 2’s orbital high and low points above the Earth, known as the apogee and perigee, respectively, have been cycling up and down.

    3
    This chart shows LightSail 2’s orbit apogee and perigee as reported by space-track.org since 8 July 2019. Sail deployment occurred on 23 July 2019.

    Right after sail deployment in July, LightSail 2’s apogee increased, while perigee decreased. In September, the trend reversed: apogee decreased, while perigee increased. In late October, the trend reversed again. And then it began reversing again in December.

    This cycle has two causes: Earth’s nonspherical shape, and its orbital motion around the Sun. Earth’s diameter at the equator is about 42 kilometers larger than it is at the poles, making its gravity stronger over the equator. This uneven gravity makes the positions of perigee and apogee precess, or wobble; if you were watching the spacecraft’s orbit from high above the north pole, you’d see it wobbling like a hula hoop spinning around your waist. While all this is happening, Earth is also revolving around the Sun, changing the angle between the light pressure from the Sun and the positions of LightSail 2’s apogee and perigee.

    Momentum management

    One of the mission’s major challenges stems from LightSail 2’s single momentum wheel, which the spacecraft uses to swing itself parallel and perpendicular to the Sun’s rays each orbit. The wheel hits a pre-defined speed limit about once per day, whereupon LightSail 2 must exit solar-sailing mode and stabilize itself with its electromagnetic torque rods.

    Early in the mission, the team was doing this manually, which proved to be inefficient, especially when communications were spotty, or when the spacecraft was suffering from other technical glitches. The process is now automated, which has improved performance. In the new paper, the team conveys an important lesson for other solar sail spacecraft in Earth orbit: managing the momentum imparted by frequent sail orientation changes is a key technical challenge.

    Power generation

    LightSail 2 only has solar cells on one side of its solar sail. LightSail 1 had a solar panel on the opposite side, but this was removed for LightSail 2’s design so engineers could install a cluster of special mirrors used to laser-range the spacecraft from Earth. This process involves zapping LightSail 2 with a laser and measuring the reflection time to more accurately determine the spacecraft’s orbit.

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    LightSail 2 with mini-DVD. LightSail 2 flew into space with a mini-DVD containing a Planetary Society member roster, a list of Kickstarter contributors, and names and images from the Society’s “Selfies to Space” campaign. Jason Davis / The Planetary Society.

    In certain orientations, LightSail 2’s solar sail entirely shadows the solar panels, and the spacecraft does not receive adequate power from the Sun, causing brownouts. The team has been able to work around brownouts by carefully managing the spacecraft’s power budget and attitude-control mode. Future solar sail spacecraft should take sail shadowing into account for mission planning.

    What’s next?

    The LightSail 2 team recently added a new control mode to the spacecraft called sun-pointing. This mode is designed to keep the solar sail face-on to the Sun throughout its full orbit. A constantly Sun-facing attitude won’t reduce orbital decay like the on/off mode does, but it reduces momentum-wheel saturation and provides a favorable orientation for battery charging. It will also test the spacecraft’s pointing accuracy, and could provide a more consistent initial attitude for starting for on-off thrust maneuvers.

    The mission team will also continue to take pictures. The technical reason for pictures is to document the sail’s condition and shape, but the pictures are also beautiful to look at for the team and public alike.

    Finally, as the orbit shrinks, the team will study the effect of the sail on the rate of orbital decay, sharing the data with other teams who are studying the use of drag sails to deorbit spacecraft.

    See the full article here. .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    3

    In 1980, Carl Sagan, Louis Friedman, and Bruce Murray founded The Planetary Society. They saw that there was enormous public interest in space, but that this was not reflected in government, as NASA’s budget was cut again and again.

    Today, The Planetary Societycontinues this work, under the leadership of CEO Bill Nye, as the world’s largest and most influential non-profit space organization. The organization is supported by over 50,000 members in over 100 countries, and by hundreds of volunteers around the world.

    Our mission is to empower the world’s citizens to advance space science and exploration. We advocate for space and planetary science funding in government, inspire and educate people around the world, and develop and fund groundbreaking space science and technology.

    We introduce people to the wonders of the cosmos, bridging the gap between the scientific community and the general public to inspire and educate people from all walks of life.

    We give every citizen of the planet the opportunity to make their voices heard in government and effect real change in support of space exploration.

    And we bring ordinary people directly to the frontier of exploration as we crowdfund innovative and exciting space technologies.

     
  • richardmitnick 1:21 pm on December 17, 2019 Permalink | Reply
    Tags: "The Biggest Little Asteroid Observatory", , , , Center for Solar System Studies, , Lately Warner and Stephens have been doing research on so-called super-rotating asteroids., Riverside Astronomical Association in Landers California., The Planetary Society   

    From The Planetary Society: “The Biggest Little Asteroid Observatory” 

    1

    From From The Planetary Society

    December 17, 2019
    Jason Davis

    Nestled among some Joshua trees in California’s Mojave Desert, about two-and-a-half-hours east of Los Angeles, you’ll find a modest cluster of one-room buildings with metal roofs. Each measures 12 by 10 feet, the biggest a structure can get in San Bernardino County without a building permit. The buildings are flanked by a modest house, a two-car garage, and small plot of solar arrays.

    About the only indication this nondescript chunk of land has anything to do with space is a yellow “METEOR CROSSING” sign on the garage. There’s no clue that the buildings are chock-full of telescopes, or that this small observatory makes big contributions to near-Earth asteroid research.

    Welcome to the Center for Solar System Studies, or CS3, a cooperative of 13 research telescopes remotely operated by 5 professional and amateur astronomers. Since 2007, The Planetary Society has awarded CS3 a total of $30,000 through its Shoemaker NEO Grant Program, which helps to find, track, and characterize near-Earth objects and determine which pose a threat to Earth.


    Hunting for Dangerous Asteroids. Bob Stevens from California tracks and characterizes dangerous near-Earth asteroids. The equipment needed for such a task doesn’t last forever. With help from our members, asteroid hunters can upgrade their equipment to make sure we find asteroids before they find us.

    “For 22 years, Planetary Society Shoemaker NEO Grants have helped small observatories like CS3 make big contributions to protecting the Earth from asteroid impacts,” said Planetary Society Chief Scientist Bruce Betts.

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    The Center for Solar System Studies in Landers, California. Jason Davis / The Planetary Society

    While scientists think we’ve discovered most of the space rocks big enough to cause planetwide devastation, only an estimated 40 percent of asteroids 140 meters wide or bigger have been found. A direct hit from an asteroid that size, slightly longer than a football field, could destroy an entire city.

    To search for those killer asteroids, professional survey telescopes around the world methodically search the night sky. A new space telescope scheduled to launch as soon as 2024 will speed up the rate of new finds. New asteroids get reported to the International Astronomical Union’s Minor Planet Center, and the search continues.

    Refining a newly discovered asteroid’s orbit and determining whether it will come close to Earth requires follow-up observations. Survey telescopes have to systematically cover the sky, so the follow-up work falls to a loose community of asteroid observers around the world. The community includes professionals funded by space agencies as well as very capable amateurs who usually have day jobs.

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    Bob Stephens at the Center for Solar System Studies. Jason Davis / The Planetary Society

    The head of CS3 is Robert Stephens, the co-owner of an accounting firm based in Rancho Cucamonga, California. Stephens recently gave The Planetary Society a tour of the CS3 facilities near Joshua Tree National Park, where the skies are dark and the air is dry—an ideal spot for observing. He unlocked one of the buildings, revealing two stout telescopes mounted to a concrete floor.

    “We don’t worry about how it looks,” he said, wiping some desert dust off the barrel of one telescope. “How it works is what’s important.”

    How it works is impressive: the telescopes are connected to a dizzying array of electronics that enable Stephens to control them from anywhere in the world, including in at least one instance from a preseason Los Angeles Lakers basketball game. There are laptops, battery backups, monitoring cameras, weather instruments, and surge protectors, all of which are programmed to operate on a schedule and can shut down gracefully in the event of a power failure. A pair of air conditioners—programmed via a thermostat and remotely operable, of course—keeps the equipment cooler than 90 degrees Fahrenheit (32 degrees Celsius) when summer temperatures soar.

    All 9 observatory buildings are set up similarly, and have roll-off roofs that close automatically in the event of a sudden rain shower. Stephens says it took him and his CS3 colleagues about 4 years to get everything built and tweaked properly. In the process, they taught themselves some new skills, like welding and building construction.

    “We learned from the school of hard knocks,” he joked.

    4
    Bob Stephens with two of his telescopes at the Center for Solar System Studies. Jason Davis / The Planetary Society

    Stephens’ interest in the night sky dates back to the 1970s, when he was in college pursuing an accounting degree. After following the lead of a friend and joining the Riverside Astronomical Society in Southern California, he experimented with astrophotography and observing variable stars. He put his hobby on hold during the 1980s to start a family and his accounting practice.

    His enthusiasm for astronomy re-ignited in the 1990s with the proliferation of charge-coupled devices, or CCDs, digital camera sensors that can collect photons during long telescopic exposures of the night sky. With the help of CCDs, amateurs could record objects too faint to see with their own eyes through their telescopes—without the hassle of developing film. Stephens got back into his old hobby, and a friend took him on a tour of Palomar Observatory northeast of San Diego. There, he met Carolyn Shoemaker and David Levy, two of the three astronomers who found comet Shoemaker-Levy 9, which slammed into Jupiter in 1994. Shoemaker and Levy were preparing for an observing run, and Shoemaker asked Stephens if he wanted to see the photographic plates used to discover Shoemaker-Levy 9.

    “I said, ‘Well, yeah—they aren’t in the Smithsonian?’ And she said, ‘Oh, no, I’ve got them right here.’ And she pulls them out of her purse,” Stephens said.

    He joined Shoemaker and Levy for dinner at one of the small houses reserved for astronomers on the mountain, and when the group returned to the telescope, they found Stephens’ car had been locked inside the observatory gates.

    “I guess you’re spending the night, huh?” he recalled Shoemaker saying. That he did, helping the two astronomers observe asteroids.

    The experience led him to a 1999 conference at Lowell Observatory in Flagstaff, Arizona that promised to train amateur astronomers how to hunt for near-Earth asteroids. There, he met Alan Harris, who was at the time a senior research scientist at NASA’s Jet Propulsion Laboratory. Harris described how amateur astronomers could aim their telescopes at an asteroid for hours at a time to collect light curves, which are plots of the brightness of the light reflected from an asteroid as it sails through space. Analysis of light curves can reveal whether an asteroid is single or binary, how fast it’s rotating, and whether it’s a solid chunk of rock or a loosely assembled pile of rubble.

    Turning light curves into actionable data is no easy task. Fortunately, the conference also featured Brian Warner, a then-amateur and now-professional astronomer who wrote a software package called Canopus to do the work automatically. Today Canopus is the world’s most commonly used software package for asteroid analysis.

    Armed with Canopus, Stephens began observing asteroids at a dark-sky site owned by the Riverside Astronomical Association in Landers, California. By then, Harris had retired from JPL, and was conducting asteroid research with Warner, who had a small observatory north of Colorado Springs. Thanks to grants from NASA and the National Science Foundation managed by the Boulder, Colorado-based Space Science Institute, Warner left his day job as a software engineer to become a professional astronomer. In 2007 he won a Planetary Society Shoemaker Grant to buy a new telescope.

    Harris and Warner soon decided it would be more efficient to manage the grants themselves, but to do so they needed to form their own company. Fortunately, they knew an accountant who could help: Bob Stephens. The trio founded a company called MoreData!, and by 2010 had transferred Harris and Warners’ grants there.

    Meanwhile, Stephens was producing impressive observing results from Landers. He soon outgrew the Riverside Astronomical Association site, and decided to purchase a nearby 5-acre property in 2011. Warner relocated his own telescope equipment there to take advantage of the better observing conditions, and thus was born the Center for Solar System Studies, or CS3. In 2013, the year CS3 officially came online, Stephens won a Planetary Society Shoemaker NEO Grant to buy a new CCD camera for his 0.4-meter telescope. Several other astronomers soon co-located to the site for asteroid research and other purposes, including Daniel Coley, who won Planetary Society grants in 2015 and 2018, both for new CCD cameras.

    Since CS3 saw first light in 2013, its telescopes have collected more than 900 light curves from close to 750 near-Earth asteroids. That’s about 60 percent of the worldwide total during that same period.

    5
    Bob Stephens with two of his telescopes at the Center for Solar System Studies. Jason Davis / The Planetary Society

    Lately, Warner and Stephens have been doing research on so-called super-rotating asteroids. From Earth, it’s difficult to tell whether an asteroid is just a loose pile of rocks barely held together by gravity, or a single, monolithic object. One way to know for sure is how fast the asteroid is spinning. Rubble-pile asteroids fly apart if they spin too fast; the threshold is about 2.2 hours per rotation, Stephens said. CS3 has found almost a quarter of the known super-rotating asteroids that spin faster than that.

    CS3 has an average of 280 clear nights per year, but on the afternoon The Planetary Society visited, a thick layer of clouds rolled in. Fortunately, there was a consolation prize: as the Sun set behind a row of mountains in the west, the sky turned shades of yellow, orange, red, and purple. Nearby Joshua trees became black silhouettes against the colorful darkening sky.

    Stephens is in the process of retiring from his accounting firm. He plans to focus more on his work at CS3, and is starting to consider his legacy, with a growing focus on easing the way for future generations of asteroid researchers. Defending the Earth from asteroids is a team sport. Sometimes asteroids pop up, get cataloged and observed, and then fade back into the depths of space, only to be re-discovered decades later. Every observation teaches us more about asteroids, and helps with planetary defense.

    “A lot of what we do is make sure we’re preserving the data so that it’s going to be available for future generations,” Stephens said. “Somebody 50, 100 years from now, in theory, can take that and use it for something.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    3

    In 1980, Carl Sagan, Louis Friedman, and Bruce Murray founded The Planetary Society. They saw that there was enormous public interest in space, but that this was not reflected in government, as NASA’s budget was cut again and again.

    Today, The Planetary Society continues this work, under the leadership of CEO Bill Nye, as the world’s largest and most influential non-profit space organization. The organization is supported by over 50,000 members in over 100 countries, and by hundreds of volunteers around the world.

    Our mission is to empower the world’s citizens to advance space science and exploration. We advocate for space and planetary science funding in government, inspire and educate people around the world, and develop and fund groundbreaking space science and technology.

    We introduce people to the wonders of the cosmos, bridging the gap between the scientific community and the general public to inspire and educate people from all walks of life.

    We give every citizen of the planet the opportunity to make their voices heard in government and effect real change in support of space exploration.

    And we bring ordinary people directly to the frontier of exploration as we crowdfund innovative and exciting space technologies.

     
  • richardmitnick 9:28 am on August 2, 2019 Permalink | Reply
    Tags: "LightSail away", , , , , , , The Planetary Society   

    From The Planetary Society via COSMOS Magazine: “LightSail away” 

    1

    From The Planetary Society

    via

    Cosmos Magazine bloc

    COSMOS Magazine

    1
    LightSail 2 during deployment, with Baja California and Mexico visible in the background. Its dual 185-degree fisheye camera lenses can each capture more than half of the sail. The Planetary Society.

    A small non-profit organisation has achieved a space-travel feat dreamed about for more than 40 years: proving that it is possible to manoeuvre a spacecraft in Earth orbit using only the power of sunbeams.

    Seven weeks ago, The Planetary Society, which has 50,000 members in 109 countries, launched a tiny, five-kilogram spacecraft into orbit, aboard a SpaceX Heavy Falcon rocket that also carried two dozen spacecraft for the US Air Force.

    From there, the spacecraft, called LightSail 2, was delivered to an orbit about 720 kilometres above the Earth.

    After preliminary tests, it deployed a boxing-ring-sized sheet of reflective Mylar film, which, since then, it has been using to “sail” on the pressure of sunlight.

    As far back as 1977, astronomer Carl Sagan – The Planetary Society’s founder – was promoting light sails as a way of propelling spacecraft.

    They work because the photons that comprise light, even though they are massless, possess momentum, causing them to exert a gentle pressure on whatever object the light falls on. That pressure can be doubled by reflecting the light with a mirror, which is why LightSail 2 uses a silvery film for its sail.

    Sagan’s dream was to use a big lightsail to propel a big spacecraft.

    “Back in the 1970s,” says The Planetary Society’s CEO, science educator Bill Nye, “the proposal was to have a solar sail a kilometre on a side that would catch up with comet Halley [after it last passed close to the Sun in 1986].”

    2

    The idea was quickly abandoned due to budget concerns and the sense that it was impractical. Revived interest, however, came from the development of miniaturised spacecraft known as CubeSats, which are constructed in blocks measuring 10 × 10 × 11.35 centimetres. (LightSail 2 is built in three of these blocks).

    Not only are these inexpensive to launch, their low mass makes them perfect for light sailing. Instead of needing a 100-hectare lightsail, like Sagan’s comet-chaser proposal, LightSail 2 only needs a 32-square-metre sail.

    The spacecraft’s small size also makes it easy to manoeuvre – important, because its operations require the orientation of its lightsail to be changed rapidly as it circles the Earth, like a sailboat tacking in changing winds.

    The results were dramatic, says Bruce Betts, the project’s chief scientist and program manager. In the eight days since the light sail was deployed, the spacecraft has raised its orbit’s apogee (the point at which it is most distant from the Earth) by 1.7 kilometres.

    “Our biggest change was a little over 900 metres, three days ago,” project manager David Spencer, an associate professor of aeronautics and astronautics at Purdue University, Indiana, told a press conference.

    LightSail 2 isn’t designed to do anything other than test the ability to use lightsails to manoeuvre. “This has been a demonstration mission all along,” says Jennifer Vaughan, The Planetary Society’s COO.

    But its success has important applications. NASA has a six-CubeSat near-Earth asteroid (NEA) mission, called NEA Scout, scheduled for launch sometime in 2020, which will also use light-sail propulsion.

    “We’ve got an agreement to share technologies and findings,” Spencer says. “We really look forward to them carrying solar sailing technology to the next level.”

    NEA Scout’s principal investigator, Les Johnson of NASA’s Marshall Spaceflight Centre, Huntsville, Alabama, agrees.

    “We are all solar sailors, wanting to achieve the same goals,” he told Cosmos shortly before LightSail 2 launched.

    And that might just be the beginning. Because lightsails don’t require fuel – and can therefore never run out of it – they are ideal for long-term missions, especially those in which spacecraft might have to do a lot of low-acceleration manoeuvring.

    For example, Nye says, they could be used to position a spacecraft between the Earth and the Sun, where it could provide as much as four to six hours of advance warning of dangerous bursts of solar radiation heading our way. Or, such a spacecraft could look outward, seeking out previously unknown asteroids that might pose a risk to the Earth.

    “Solar sails are uniquely suited to positioning themselves, station keeping, in orbits closer to the Sun than the Earth’s orbit,” Nye says.

    They can also be used to hold spacecraft in orbits around the Earth that are not otherwise stable, such as one that puts a satellite permanently above one of the Earth’s poles. Or, they can be used for long missions to multiple asteroids, the Outer Solar System, or even to other stars.

    With a normal spacecraft, Nye says, the fuel eventually runs out. “This fuel never runs out.”

    Meanwhile, LightSail 2’s mission isn’t over. “We’re still working to improve sail control,” Spencer says.

    The short-term goal, he says, will be to continue working to raise the spacecraft’s apogee. But the manner in which that is being done has the side effect of lowering the spacecraft’s perigee (its closest approach to the Earth).

    And, even though it’s 700 kilometres above the Earth’s surface, there’s enough of our planet’s tenuous exosphere up there to exert drag on such a lightweight spacecraft. “As perigee moves lower, the atmosphere is going to cause more drag, to the point where it’s going to be impossible for us to overcome that drag,” Spencer says.

    It would be possible, he adds, to employ different sailing techniques to raise the spacecraft’s perigee, along with its apogee, but that wasn’t the goal of the mission. “It’s certainly possible from a physics standpoint to do that, but that’s not in our near-term plan,” he says.

    Instead, LightSail 2 will then use its sail to study the drag of the far-outer atmosphere, until the spacecraft eventually falls back to Earth and burns up.

    Meanwhile, Nye says that in addition to its scientific objectives, the mission has achieved to other important goals.

    First, it was conducted at about “one-twentieth” the cost that would have been incurred by a “regular” space agency like NASA.

    Sure, more money would have been nicer – if for no other reason than to allow the control team to talk to the spacecraft throughout its orbit, rather than just when it was above one of their few tracking stations. “But nevertheless, we were able to pull it off,” Nye says.

    But more importantly, he says only days after the anniversary of the first Apollo Moon landing, “it shows, once again, that space exploration brings out the best in us.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    3

    In 1980, Carl Sagan, Louis Friedman, and Bruce Murray founded The Planetary Society. They saw that there was enormous public interest in space, but that this was not reflected in government, as NASA’s budget was cut again and again.

    Today, The Planetary Society continues this work, under the leadership of CEO Bill Nye, as the world’s largest and most influential non-profit space organization. The organization is supported by over 50,000 members in over 100 countries, and by hundreds of volunteers around the world.

    Our mission is to empower the world’s citizens to advance space science and exploration. We advocate for space and planetary science funding in government, inspire and educate people around the world, and develop and fund groundbreaking space science and technology.

    We introduce people to the wonders of the cosmos, bridging the gap between the scientific community and the general public to inspire and educate people from all walks of life.

    We give every citizen of the planet the opportunity to make their voices heard in government and effect real change in support of space exploration.

    And we bring ordinary people directly to the frontier of exploration as we crowdfund innovative and exciting space technologies.

     
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