vendredi 21 octobre 2016

NASA Establishes the Small Spacecraft Systems Virtual Institute












NASA patch.

Oct. 21, 2016

Small satellites or CubeSats launched in space from ISS. Image Credit: NASA

NASA announces the addition of its newest virtual institute to advance the field of small spacecraft systems. The Small Spacecraft Systems Virtual Institute (S3VI), hosted at NASA’s Ames Research Center in Moffett Field, California, will leverage the growing small spacecraft community, promote innovation, identify emerging technology opportunities, and provide an efficient channel for communication about small spacecraft systems with industry, academia, and other government agencies.

“NASA sees enormous benefits from investing in research and technology development in small spacecraft systems, such as propulsion, that will be essential in advancing the commercial space sector,” said Steve Jurczyk, associate administrator for NASA’s Space Technology Mission Directorate (STMD). “Over the past several years, NASA has increased the generation of new, innovative applications of small spacecraft, with several mission directorates using small spacecraft to meet their goals.”

STMD established the Small Spacecraft Technology Program in 2011 to develop and demonstrate the unique capabilities of small spacecraft to support science, exploration and space operations. The Science Mission Directorate (SMD) and the Human Exploration and Operations Mission Directorate (HEOMD) each are using small spacecraft for a range of activities: earth and space science measurements to help understand our environment; investigations of microgravity effects on organisms to enable the safe exploration of space; and robotic precursors to maximize the productive use of space.


Animation above: Taken by astronauts on May 16, 2016, these images show a CubeSat deployment from the International Space Station. The bottom-most CubeSat is the NASA-funded MinXSS CubeSat, built by the University of Colorado, Boulder. Animation Credit: NASA.

The S3VI will coordinate with key activities such as STMD’s Cube Quest Challenge and HEOMD’s CubeSat Launch Initiative (CLSI). These efforts will continue to offer opportunities for university students and industry to fly small spacecraft as auxiliary payloads on NASA launches.

“The S3VI will provide the first one-stop shop for technical knowledge in the rapidly burgeoning small spacecraft technology fields,” said Jay Bookbinder, director of programs and projects at Ames. “This will result in more efficient development efforts, and enable smaller vendors to compete more effectively in this market.”

Depending on the mission objective, a small spacecraft can range in size from a postage-stamp (under an ounce) up to the size of a refrigerator (about 400 pounds). Many recently launched NASA small spacecraft conform to the CubeSat standards - established by academia - in which a single cube (called a one-unit, or 1U) measures about 4 inches on each side, has an approximate volume of one quart, and weighs less than three pounds. The variety of sizes offers spacecraft capabilities tailored to specific science instruments, exploration sensors, or technology demonstrations.

Over the next year, the S3VI will establish both a physical and virtual presence within NASA and the small spacecraft community at large. Strategic direction and tactical focus for the Institute will result from a series of community activities and workshops. The S3VI will engage with the small spacecraft communities, including academia, industry, and other government agencies to:

- Establish the Institute as the common portal into NASA for all small spacecraft activities. The Institute will capture information on small spacecraft activities and lessons learned; identify small spacecraft collaborative opportunities; and identify NASA points of contact for a variety of small spacecraft activities across the centers.

- Engage subject matter experts from across the small spacecraft communities to define the technical scope, policy issues and direction for the Institute.

- Host the Small Spacecraft Body of Knowledge (SSBK) as an online resource. This includes STMD’s Small Spacecraft Technology State of the Art report, a small spacecraft lessons learned library, a systems test data repository, reliability practices, etc.

The S3VI portal will go live in early 2017, and is jointly sponsored by NASA’s Space Technology Mission Directorate and the Science Mission Directorate. The S3VI is hosted at and managed by NASA’s Ames Research Center in Moffett Field, California.

For more information about the Space Technology Mission Directorate, visit: http://www.nasa.gov/spacetech

For more information about the Science Mission Directorate, visit: https://science.nasa.gov

For more information about small satellites, visit: http://www.nasa.gov/smallsats

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Ames Research Center/Loura Hall.

Greetings, Orbiter.ch

Changing Colors in Saturn's North












NASA Cassini-Huygens Mission to Saturn & Titan patch.

Oct. 21, 2016


These two natural color images from NASA's Cassini spacecraft show the changing appearance of Saturn's north polar region between 2012 and 2016.

Scientists are investigating potential causes for the change in color of the region inside the north-polar hexagon on Saturn. The color change is thought to be an effect of Saturn's seasons. In particular, the change from a bluish color to a more golden hue may be due to the increased production of photochemical hazes in the atmosphere as the north pole approaches summer solstice in May 2017.

Researchers think the hexagon, which is a six-sided jetstream, might act as a barrier that prevents haze particles produced outside it from entering. During the seven-year-long Saturnian winter, the polar atmosphere became clear of aerosols produced by photochemical reactions -- reactions involving sunlight and the atmosphere. Since the planet experienced equinox in August 2009, the polar atmosphere has been basking in continuous sunshine, and aerosols are being produced inside of the hexagon, around the north pole, making the polar atmosphere appear hazy today.

Other effects, including changes in atmospheric circulation, could also be playing a role. Scientists think seasonally shifting patterns of solar heating probably influence the winds in the polar regions.

Both images were taken by the Cassini wide-angle camera.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org and ESA's website http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Image, Text, Credits: NASA/Tony Greicius/JPL-Caltech/Space Science Institute/Hampton.University.

Best regards, Orbiter.ch

NASA, Citizen Scientists Discover Potential New Hunting Ground for Exoplanets











NASA logo.

Oct. 21, 2016


Image above: Artist’s concept of the newly discovered disk. Image Credits: Jonathan Holden.

Via a NASA-led citizen science project, eight people with no formal training in astrophysics helped discover what could be a fruitful new place to search for planets outside our solar system – a large disk of gas and dust encircling a star known as a circumstellar disk.

A paper, published in The Astrophysical Journal Letters and coauthored by eight citizen scientists involved in the discovery, describes a newly identified red dwarf star, AWI0005x3s, and its warm circumstellar disk, the kind associated with young planetary systems. Most of the exoplanets, which are planets outside our solar system, that have been imaged to date dwell in disks similar to the one around AWI0005x3s.

The disk and its star are located in what is dubbed the Carina association – a large, loose grouping of similar stars in the Carina Nebula approximately 212 light years from our sun. Its relative proximity to Earth will make it easier to conduct follow-on studies.

"Most disks of this kind fade away in less than 30 million years," said Steven Silverberg, a graduate student at Oklahoma University and lead author of the paper. "This particular red dwarf is a candidate member of the Carina association, which would make it around 45 million years old. It's the oldest red dwarf system with a disk we've seen in one of these associations."

Since the launch of NASA’s Disk Detective website in January 2014, approximately 30,000 citizen scientists have performed roughly two million classifications of stellar objects, including those that led to this discovery. Through Disk Detective, citizen scientists study data from NASA’s Wide-field Infrared Survey Explorer mission (WISE), the agency’s Two-Micron All Sky Survey project, and other stellar surveys.

"Without the help of the citizen scientists examining these objects and finding the good ones, we might never have spotted this object," said Marc Kuchner, an astrophysicist at NASA’s Goddard Space Fight Center in Greenbelt, Maryland, who leads Disk Detective. "The WISE mission alone found 747 million objects, of which we expect a few thousand to be circumstellar disks.”

The eight citizen scientist co-authors, members of an advanced user group, volunteered to help by researching disk candidates. Their data led to the discovery of this new disk.

“I’ve loved astronomy since childhood and wanted to be part of the space program, as did every boy my age,” adds Milton Bosch, a citizen scientist co-author from California. “I feel very fortunate to be part of such a great group of dedicated people, and am thrilled to partake in this adventure of discovery and be a co-author on this paper.”

Disk Detective is a collaboration between NASA, Zooniverse, the University of Oklahoma, University of Córdoba in Argentina, National Astronomical Observatory of Japan, Space Telescope Science Institute, Harvard-Smithsonian Center for Astrophysics, Carnegie Institution of Washington, University of Hawaii and Korea Astronomy and Space Science Institute.

To learn more about opportunities for the public to participate in NASA science and technology projects, visit: http://www.nasa.gov/solve

The Astrophysical Journal Letters: http://iopscience.iop.org/article/10.3847/2041-8205/830/2/L28/meta

NASA’s Disk Detective website: https://www.diskdetective.org/

NASA’s Wide-field Infrared Survey Explorer mission (WISE): https://www.nasa.gov/mission_pages/WISE/main/

Image (mentioned), Text, Credits: NASA/Sarah Ramsey.

Best regards, Orbiter.ch

Photonics Dawning as the Communications Light For Evolving NASA Missions












NASA - Goddard Space Flight Center logo.

Oct. 21, 2016

A largely unrecognized field called photonics may provide solutions to some of NASA’s most pressing challenges in future spaceflight.

Photonics explores the many applications of generating, detecting and manipulating photons, or particles of light that, among other things, make up laser beams. On this day in 1983, the General Conference of Weights and Measures adopted the accepted value for the speed of light, an important photonics milestone. Oct. 21, 2016, is Day of Photonics, a biennial event to raise awareness of photonics to the general public. The study has multiple applications across NASA missions, from space communications to reducing the size of mission payloads to performing altitude measurements from orbit.

video
NASA and Photonics: Making the Connection

Video above: NASA is using photonics to solve some of the most pressing upcoming challenges in spaceflight, such as better data communications from space to Earth. Video Credits: NASA's Goddard Space Flight Center/Amber Jacobson, producer.

One major NASA priority is to use lasers to make space communications for both near-Earth and deep-space missions more efficient. NASA’s communications systems have matured over the decades, but they still use the same radio-frequency (RF) system developed in the earliest days of the agency. After more than 50 years of using solely RF, NASA is investing in new ways to increase data rates while also finding more efficient communications systems.

Photonics may provide the solution. Several centers across NASA are experimenting with laser communications, which has the potential to provide data rates at least 10 to 100 times better than RF. These higher speeds would support increasingly sophisticated instruments and the transmission of live video from anywhere in the solar system. They would also increase the bandwidth for communications from human exploration missions in deep space, such as those associated with Journey to Mars.

NASA’s Goddard Space Flight Center in Greenbelt, Maryland, launched the first laser communications pathfinder mission in 2013. The Lunar Laser Communications Demonstration (LLCD) proved that a space-based laser communications system was viable and that the system could survive both launch and the space environment. But the mission was short-lived by design, as the host payload crashed into the lunar surface in a planned maneuver a few months after launch.


Animation above: Conceptual animation depicting a satellite using lasers to relay data from Mars to Earth. Animation Credits: NASA's Goddard Space Flight Center.

The Goddard team is now planning a follow-on mission called the Laser Communications Relay Demonstration (LCRD) to prove the proposed system’s longevity. It will also provide engineers more opportunity to learn the best way to operate it for near-Earth missions.

“We have been using RF since the beginning, 50 to 60 years, so we’ve learned a lot about how it works in different weather conditions and all the little things to allow us to make the most out of the technology, but we don’t have that experience with laser comm,” said Dave Israel, Exploration and Space Communications architect at Goddard and principal investigator on LCRD. “LCRD will allow us to test the performance over all different weather conditions and times of day and learn how to make the most of laser comm.”

Scheduled to launch in 2019, LCRD will simulate real communications support, practicing for two years with a test payload on the International Space Station and two dedicated ground stations in California and Hawaii. The mission could be the last hurdle to implementing a constellation of laser communications relay satellites similar to the Space Network’s Tracking and Data Relay Satellites.

NASA’s Jet Propulsion Laboratory in Pasadena, California, and Glenn Research Center in Cleveland are also following up on LLCD’s success. But both will focus on how laser communications could be implemented in deep-space missions.

Missions to deep space impose special communication challenges because of their distance from Earth. The data return on these missions slowly trickle back to the ground a little at a time using radio frequency. Laser communications could significantly improve data rates in all space regions, from low-Earth orbit to interplanetary.

JPL’s concept, called Deep Space Optical Communications (DSOC), focuses on laser communications’ benefits to data rates and to space and power constraints on missions. The data-rate benefits of laser communications for deep-space missions are clear, but less recognized is that laser communications can also save mass, space and/or power requirements on missions. That could be monumental on missions like the James Webb Space Telescope, which is so large that, even folded, it will barely fit in the largest rocket currently available. Although Webb is an extreme example, many missions today face size constraints as they become more complex. The Lunar Reconnaissance Orbiter mission carried both types of communications systems, and the laser system was half the mass, required 25 percent less power and transferred data at six times the rate of the RF system. Laser communications could also benefit a class of missions called CubeSats, which are about the size of a shoebox. These missions are becoming more popular and require miniaturized parts, including communications and power systems.

Power requirements can become a major challenge on missions to the outer solar system. As spacecraft move away from the sun, solar power becomes less viable, so the less power a payload requires, the smaller the spacecraft battery, saving space, and the easier spacecraft components can be recharged.

Laser communications could help to solve all of these challenges.

The team at Glenn is developing an idea called Integrated Radio and Optical Communications (iROC) to put a laser communications relay satellite in orbit around Mars that could receive data from distant spacecraft and relay their signal back to Earth. The system would use both RF and laser communications, promoting interoperability amongst all of NASA’s assets in space. By integrating both communications systems, iROC could provide services both for new spacecraft using laser communications systems and older spacecraft like Voyager 1 that use RF.

But laser communications is not NASA’s only foray into photonics, nor is it the first. In fact, NASA began using lasers shortly after they were invented. Goddard successfully demonstrated satellite laser ranging, a technique to measure distances, in 1964.

Satellite Laser Ranging is still managed at Goddard. The system uses laser stations worldwide to bounce short pulses of light off of special reflectors installed on satellites. There are also reflectors on the moon that were placed there during the Apollo and Soviet rover programs. By timing the bounce of the pulses, engineers can compute distances and orbits. Measurements are accurate up to a few millimeters. This application is used on numerous NASA missions, such as ICESat-2, which will measure the altitude of the ice surface in the Antarctic and Greenland regions. It will provide important information regarding climate and the health of Earth’s polar regions.

NASA’s Satellite Laser Ranging system consists of eight stations covering North America, the west coast of South America, the Pacific, South Africa and western Australia. NASA and its partners and associated universities operate the stations. SLR is part of the larger International Laser Ranging Service, and NASA’s contribution comprises more than a third of the organization’s total data volume.

From communications to altimetry and navigation, photonics’ importance to NASA missions cannot be understated. As technology continues to evolve, many photonics applications may come to fruition over the next several decades. Others may also be discovered, especially as humanity pushes further out into the universe than ever before.

To find out more, visit http://day-of-photonics.org/.

Related links:

Lunar Laser Communications Demonstration (LLCD): http://esc.gsfc.nasa.gov/267/271.html

Laser Communications Relay Demonstration (LCRD): http://www.nasa.gov/mission_pages/tdm/lcrd/index.html

Tracking and Data Relay Satellites: http://www.nasa.gov/directorates/heo/scan/services/networks/txt_tdrs.html

Deep Space Optical Communications (DSOC): https://gameon.nasa.gov/projects/deep-space-optical-communications-dsoc/

Integrated Radio and Optical Communications (iROC): https://spaceflightsystems.grc.nasa.gov/sopo/scsmo/scan-technology/iroc/

Animation (mentioned), Video (mentioned), Text, Credits: NASA's Goddard Space Flight Center, by Ashley Hume/Rob Garner.

Greetings, Orbiter.ch

'Heartbeat Stars' Unlocked in New Study












NASA - Kepler Space Telescope patch.

Oct. 21, 2016


Image above: This artist's concept depicts "heartbeat stars," which have been detected by NASA's Kepler Space Telescope and others. Image Credits: NASA/JPL-Caltech.

Matters of the heart can be puzzling and mysterious -- so too with unusual astronomical objects called heartbeat stars.

Heartbeat stars, discovered in large numbers by NASA's Kepler space telescope, are binary stars (systems of two stars orbiting each other) that got their name because if you were to map out their brightness over time, the result would look like an electrocardiogram, a graph of the electrical activity of the heart. Scientists are interested in them because they are binary systems in elongated elliptical orbits. This makes them natural laboratories for studying the gravitational effects of stars on each other.

In a heartbeat star system, the distance between the two stars varies drastically as they orbit each other. Heartbeat stars can get as close as a few stellar radii to each other, and as far as 10 times that distance during the course of one orbit.

At the point of their closest encounter, the stars’ mutual gravitational pull causes them to become slightly ellipsoidal in shape, which is one of the reasons their light is so variable. This is the same type of "tidal force" that causes ocean tides on Earth. By studying heartbeat stars, astronomers can gain a better understanding of how this phenomenon works for different kinds of stars.

Tidal forces also cause heartbeat stars to vibrate or "ring" -- in other words, the diameters of the stars rapidly fluctuate as they orbit each other. This effect is most noticeable at the point of closest approach.

“You can think about the stars as bells, and once every orbital revolution, when the stars reach their closest approach, it's as if they hit each other with a hammer,” said Avi Shporer, NASA Sagan postdoctoral fellow at NASA's Jet Propulsion Laboratory, Pasadena, California, and lead author of a recent study on heartbeat stars. "One or both stars vibrate throughout their orbits, and when they get nearer to each other, it's as though they are ringing very loudly."    

Kepler, now in its K2 Mission, discovered large numbers of heartbeat stars just in the last several years. A 2011 study discussed a star called KOI-54 that shows an increase in brightness every 41.8 days. In 2012, a subsequent study characterized 17 additional objects in the Kepler data and dubbed them "heartbeat stars." To characterize these unique systems, further data and research were required.

Shporer's study, published in the Astrophysical Journal, measured the orbits of 19 heartbeat star systems -- the largest batch ever characterized in a single study. The authors followed up on known heartbeat stars, previously identified by the Kepler mission. Specifically, they used an instrument on the W.M. Keck Observatory telescope in Hawaii called the High Resolution Echelle Spectrometer (HIRES), which measures the wavelengths of incoming light, which are stretched out when a star is moving away from us and shorter in motion toward us. This information allows astronomers to calculate the speed of the objects along the line of sight, and measure the shape of the orbit.

"We found that the heartbeat stars in our sample tend to be hotter than the sun and bigger than the sun," Shporer said. "But it is possible that there are others with different temperature ranges that we did not yet measure."

Kepler Space Telescope. Image Credits: NASA/JPL-Caltech

Study authors also postulate that some binary systems of heartbeat stars could have a third star in the system that has not yet been detected, or even a fourth star.

“The mere existence of heartbeat stars is a bit of a puzzle," said Susan Mullally (formerly Thompson), a SETI Institute scientist working for the Kepler Mission at NASA's Ames Research Center in Moffett Field, California, and co-author of the study. "All the tidal stretching of these heartbeat stars should have quickly caused the system to evolve into a circular orbit. A third star in the system is one way to create the highly stretched-out, elliptical orbits we observe."

Researchers are currently pursuing follow-up studies to search for third-star components in heartbeat star systems.

"We look forward to continued collaboration between ground and space observatories to better understand the complex inner workings of heartbeat stars," Shporer said.

NASA Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. JPL managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. Work on this study was performed in part under contract with JPL funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute.

Astrophysical Journal: http://iopscience.iop.org/article/10.3847/0004-637X/829/1/34

For more information about the Kepler and K2 missions, visit: http://www.nasa.gov/kepler

Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL, written by Elizabeth Landau/Ames Research Center/Michele Johnson.

Greetings, Orbiter.ch

Uranus May Have Two Undiscovered Moons










NASA - Voyager 1 & 2 Mission patch.

Oct. 21, 2016

NASA's Voyager 2 spacecraft flew by Uranus 30 years ago, but researchers are still making discoveries from the data it gathered then. A new study led by University of Idaho researchers suggests there could be two tiny, previously undiscovered moonlets orbiting near two of the planet’s rings.

Rob Chancia, a University of Idaho doctoral student, spotted key patterns in the rings while examining decades-old images of Uranus' icy rings taken by Voyager 2 in 1986. He noticed the amount of ring material on the edge of the alpha ring -- one of the brightest of Uranus' multiple rings -- varied periodically. A similar, even more promising pattern occurred in the same part of the neighboring beta ring.

"When you look at this pattern in different places around the ring, the wavelength is different -- that points to something changing as you go around the ring. There's something breaking the symmetry," said Matt Hedman, an assistant professor of physics at the University of Idaho, who worked with Chancia to investigate the finding. Their results will be published in The Astronomical Journal and have been posted to the pre-press site arXiv.


Image above: Uranus is seen in this false-color view from NASA's Hubble Space Telescope from August 2003. The brightness of the planet's faint rings and dark moons has been enhanced for visibility. Image Credits: NASA/Erich Karkoschka (Univ. Arizona).

Chancia and Hedman are well-versed in the physics of planetary rings: both study Saturn's rings using data from NASA's Cassini spacecraft, which is currently orbiting Saturn. Data from Cassini have yielded new ideas about how rings behave, and a grant from NASA allowed Chancia and Hedman to examine Uranus data gathered by Voyager 2 in a new light. Specifically, they analyzed radio occultations -- made when Voyager 2 sent radio waves through the rings to be detected back on Earth -- and stellar occultations, made when the spacecraft measured the light of background stars shining through the rings, which helps reveal how much material they contain.

They found the pattern in Uranus' rings was similar to moon-related structures in Saturn's rings called moonlet wakes.

The researchers estimate the hypothesized moonlets in Uranus' rings would be 2 to 9 miles (4 to 14 kilometers) in diameter -- as small as some identified moons of Saturn, but smaller than any of Uranus' known moons. Uranian moons are especially hard to spot because their surfaces are covered in dark material.

"We haven't seen the moons yet, but the idea is the size of the moons needed to make these features is quite small, and they could have easily been missed," Hedman said. "The Voyager images weren't sensitive enough to easily see these moons."

Hedman said their findings could help explain some characteristics of Uranus' rings, which are strangely narrow compared to Saturn's. The moonlets, if they exist, may be acting as "shepherd" moons, helping to keep the rings from spreading out. Two of Uranus' 27 known moons, Ophelia and Cordelia, act as shepherds to Uranus' epsilon ring.

“The problem of keeping rings narrow has been around since the discovery of the Uranian ring system in 1977 and has been worked on by many dynamicists over the years,” Chancia said. “I would be very pleased if these proposed moonlets turn out to be real and we can use them to approach a solution.”

NASA's Voyager 2 spacecraft Uranus flyby. Image Credit: NASA

Confirming whether or not the moonlets actually exist using telescope or spacecraft images will be left to other researchers, Chancia and Hedman said. They will continue examining patterns and structures in Uranus’ rings, helping uncover more of the planet’s many secrets.

"It's exciting to see Voyager 2's historic Uranus exploration still contributing new knowledge about the planets," said Ed Stone, project scientist for Voyager, based at Caltech, Pasadena, California.

Voyager 2 and its twin, Voyager 1, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn, and Voyager 2 also flew by Uranus and Neptune. Voyager 2 is the longest continuously operated spacecraft. It is expected to enter interstellar space in a few years, joining Voyager 1, which crossed over in 2012. Though far past the planets, the mission continues to send back unprecedented observations of the space environment in the solar system, providing crucial information on the environment our spacecraft travel through as we explore farther and farther from home.

NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, built the twin Voyager spacecraft and operates them for the Heliophysics Division within NASA's Science Mission Directorate in Washington.

The Astronomical Journal: http://iopscience.iop.org/journal/1538-3881

Pre-press site arXiv: https://arxiv.org/abs/1610.02376

For more information about Voyager, visit: http://voyager.jpl.nasa.gov

Images (mentioned), Text, Credits: NASA, written by Tara Roberts/Tony Greicius/JPL/Elizabeth Landau/University of Idaho Communications/Tara Roberts.

Greetings, Orbiter.ch

Mars Reconnaissance Orbiter Views Schiaparelli Landing Site














NASA - Mars Reconnaissance Orbiter (MRO) logo / ESA & ROSCOSMOS - ExoMars Mission patch.

21 October 2016


Image above: Artist's view of Mars Reconnaissance Orbiter (MRO) orbiting Mars. Image Credits: NASA/JPL-Caltech.

NASA’s Mars Reconnaissance Orbiter has identified new markings on the surface of the Red Planet that are believed to be related to ESA’s ExoMars Schiaparelli entry, descent and landing technology demonstrator module.

Schiaparelli entered the martian atmosphere at 14:42 GMT on 19 October for its 6-minute descent to the surface, but contact was lost shortly before expected touchdown. Data recorded by its mothership, the Trace Gas Orbiter, are currently being analysed to understand what happened during the descent sequence.

 Mars Reconnaissance Orbiter view of Schiaparelli landing site

In the meantime, the low-resolution CTX camera on-board the Mars Reconnaissance Orbiter (MRO) took pictures of the expected touchdown site in Meridiani Planum on 20 October as part of a planned imaging campaign.

The image released today has a resolution of 6 metres per pixel and shows two new features on the surface when compared to an image from the same camera taken in May this year.

Schiaparelli landing site

One of the features is bright and can be associated with the 12-m diameter parachute used in the second stage of Schiaparelli’s descent, after the initial heat shield entry. The parachute and the associated back shield were released from Schiaparelli prior to the final phase, during which its nine thrusters should have slowed it to a standstill just above the surface.

The other new feature is a fuzzy dark patch roughly 15 x 40 metres in size and about 1 km north of the parachute. This is interpreted as arising from the impact of the Schiaparelli module itself following a much longer free fall than planned, after the thrusters were switched off prematurely.

Estimates are that Schiaparelli dropped from a height of between 2 and 4 kilometres, therefore impacting at a considerable speed, greater than 300 km/h. The relatively large size of the feature would then arise from disturbed surface material. It is also possible that the lander exploded on impact, as its thruster propellant tanks were likely still full. These preliminary interpretations will be refined following further analysis.

A closer look at these features will be taken next week with HiRISE, the highest-resolution camera onboard MRO. These images may also reveal the location of the front heat shield, dropped at higher altitude.

MRO image of Schiaparelli – before

Since the module’s descent trajectory was observed from three different locations, the teams are confident that they will be able to reconstruct the chain of events with great accuracy. The exact mode of anomaly onboard Schiaparelli is still under investigation.

The two new features are located at 353.79 degrees east longitude, 2.07 degrees south latitude on Mars. The position of the dark mark shows that Schiaparelli impacted approximately 5.4 km west of its intended landing point, well within the nominal 100 x 15 km landing ellipse.

Meanwhile, the teams continue to decode the data extracted from the recording of Schiaparelli descent signals recorded by the ExoMars TGO in order to establish correlations with the measurements made with the Giant Metrewave Radio Telescope (GMRT), an experimental telescope array located near Pune, India, and with ESA’s Mars Express from orbit.

A substantial amount of extremely valuable Schiaparelli engineering data were relayed back to the TGO during the descent and is being analysed by engineers day and night.

MRO image of Schiaparelli – after

The ExoMars TGO orbiter is currently on a 101 000 km x 3691 km orbit (with respect to the centre of the planet) with a period of 4.2 days, well within the planned initial orbit. The spacecraft is working very well and will take science calibration data during two orbits in November 2016.

It will then be ready for the planned aerobraking manoeuvres starting in March 2017 and continuing for most of the year, bringing it into a 400-km altitude circular orbit around Mars.

The TGO will then begin its primary science mission to study the atmosphere of Mars in search of possible indications of life below the surface, and to act as a telecommunications relay station for the ExoMars 2020 rover and other landed assets.

Related links:

NASA's Mars Reconnaissance Orbiter (MRO): http://www.nasa.gov/mission_pages/MRO/main/index.html

ESA Robotic exploration of Mars: http://exploration.esa.int/

Roscosmos: http://en.federalspace.ru/

ExoMars at IKI: http://exomars.cosmos.ru/

Thales Alenia Space: https://www.thalesgroup.com/en/worldwide/space/space

NASA In 2016 ExoMars orbiter (Electra radio): http://mars.nasa.gov/programmissions/missions/future/exomarsorbiter2016/

Where on Mars?: http://whereonmars.co/

More about...

ExoMars Factsheet: http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_Factsheet

ExoMars frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_frequently_asked_questions

ExoMars brochure: http://www.esa.int/About_Us/ESA_Publications/ESA_Publications_Brochures/ESA_BR-327_EXOMARS_2016

Images, Text, Credits: NASA/JPL-Caltech/MSSS, Arizona State University; inserts: NASA/JPL-Caltech/MSSS/ESA/Thierry Blancquaert/Markus Bauer.

Greetings, Orbiter.ch

Hubble Spins a Web Into a Giant Red Spider Nebula












NASA - Hubble Space Telescope patch.

Oct. 21, 2016


Huge waves are sculpted in this two-lobed nebula called the Red Spider Nebula, located some 3,000 light-years away in the constellation of Sagittarius. This warm planetary nebula harbors one of the hottest stars known and its powerful stellar winds generate waves 100 billion kilometers (62.4 billion miles) high. The waves are caused by supersonic shocks, formed when the local gas is compressed and heated in front of the rapidly expanding lobes. The atoms caught in the shock emit the spectacular radiation seen in this image.

video
Hubble orbiting Earth

For images and more information about Hubble Space Telescope, visit:

http://hubblesite.org/
http://www.nasa.gov/hubble
http://www.spacetelescope.org/

Text Credits: ESA (European Space Agency)/NASA/Rob Garner/Image, Video, Credits: ESA (European Space Agency)/Garrelt Mellema (Leiden University, the Netherlands).

Greetings, Orbiter.ch

Expedition 49 Welcomes Three New Crew Members












ROSCOSMOS - Soyuz MS-02 Mission patch.

October 21, 2016

video
Expedition 49-50 Crew Docks to the Space Station

Three new crew members are aboard the International Space Station. The hatches on the space station and Soyuz MS-02 opened at 8:20 a.m. EDT, marking the arrival to the orbiting laboratory for NASA astronaut Shane Kimbrough and cosmonauts Sergey Ryzhikov and Andrey Borisenko of the Russian space agency Roscosmos.


Image above: The Soyuz MS-02 spacecraft carrying three Expedition 49-50 crew members slowly approaches the space station. Image Credit: NASA TV.

Their Soyuz MS-02 spacecraft docked with the station’s Poisk module at 5:52 a.m. At the time of docking, the space station was flying 251 miles over southern Russia.

The trio join Expedition 49 Commander Anatoly Ivanishin of Roscosmos and Flight Engineers Kate Rubins of NASA and Takuya Onishi of the Japan Aerospace Exploration Agency, who have been aboard the complex since July. The incoming crew will spend a little more than four months together aboard the space station, returning to Earth in late February.


Image above: The new six-member Expedition 49 crew gathers in the Zvezda service module. The three newest arrivals (front row from left) Andrey Borisenko, Sergey Ryzhikov and Shane Kimbrough talk to family members and mission officials back on Earth. In the back row from left are, Kate Rubins, Anatoly Ivanishin and Takuya Onishi. Image Credit: NASA TV.

The crew members will contribute to more than 250 research experiments ongoing aboard the space station, in diverse fields such as biology, Earth Science, human research, physical sciences and technology development.

To learn more about the International Space Station, visit: http://www.nasa.gov/station

To follow activities on orbit, visit the space station Facebook page at: http://www.facebook.com/ISS

Follow the crew members and the station on Twitter at: http://www.twitter.com/nasa_astronauts and http://www.twitter.com/Space_Station

Follow the station on Instagram at: https://instagram.com/iss/

Expedition 49: http://www.nasa.gov/mission_pages/station/expeditions/expedition49/index.html

Images (mentioned), Video, Text, Credits: NASA/NASA TV/Mark Garcia.

Best regards, Orbiter.ch

jeudi 20 octobre 2016

Tracking Waves from Sunspots Gives New Solar Insight















NASA - Solar Dynamics Observatory (SDO) patch / NASA - Interface Region Imaging Spectrograph (IRIS) patch.

Oct. 20, 2016

While it often seems unvarying from our viewpoint on Earth, the sun is constantly changing. Material courses through not only the star itself, but throughout its expansive atmosphere. Understanding the dance of this charged gas is a key part of better understanding our sun – how it heats up its atmosphere, how it creates a steady flow of solar wind streaming outward in all directions, and how magnetic fields twist and turn to create regions that can explode in giant eruptions. Now, for the first time, researchers have tracked a particular kind of solar wave as it swept upward from the sun's surface through its atmosphere, adding to our understanding of how solar material travels throughout the sun.


Animation above: Scientists analyzed sunspot images from a trio of observatories -- including the Big Bear Solar Observatory, which captured this footage -- to make the first-ever observations of a solar wave traveling up into the sun’s atmosphere from a sunspot. Animation Credits: BBSO/Zhao et al.

Tracking solar waves like this provides a novel tool for scientists to study the atmosphere of the sun. The imagery of the journey also confirms existing ideas, helping to nail down the existence of a mechanism that moves energy – and therefore heat – into the sun’s mysteriously-hot upper atmosphere, called the corona. A study on these results was published Oct. 11, 2016, in The Astrophysical Journal Letters.

“We see certain kinds of solar seismic waves channeling upwards into the lower atmosphere, called the chromosphere, and from there, into the corona,” said Junwei Zhao, a solar scientist at Stanford University in Stanford, California, and lead author on the study. “This research gives us a new viewpoint to look at waves that can contribute to the energy of the atmosphere.”

The study makes use of the wealth of data captured by NASA’s Solar Dynamics Observatory, NASA’s Interface Region Imaging Spectrograph, and the Big Bear Solar Observatory in Big Bear Lake, California. Together, these observatories watch the sun in 16 wavelengths of light that show the sun’s surface and lower atmosphere. SDO alone captures 11 of these.

“SDO takes images of the sun in many different wavelengths at a high time resolution,” said Dean Pesnell, SDO project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That lets you see the frequencies of these waves – if you didn’t have such rapid-fire images, you’d lose track of the waves from one image to the next.”

 Solar Dynamics Observatory. Image Credit: NASA

Though scientists have long suspected that the waves they spot in the sun’s surface, called the photosphere, are linked to those seen in the lowest reaches of the sun’s atmosphere, called the chromosphere, this new analysis is the first time that scientists have managed to actually watch the wave travel up through the various layers into the sun’s atmosphere.

When material is heated to high temperatures, it releases energy in the form of light. The type, or wavelength, of that light is determined by what the material is, as well as its temperature.  That means different wavelengths from the sun can be mapped to different temperatures of solar material. Since we know how the sun’s temperature changes throughout the layers of its atmosphere, we can then order these wavelengths according to their height above the surface – and essentially watch solar waves as they travel upwards.

The implications of this study are twofold – first, this technique for watching the waves itself gives scientists a new tool to understand the sun’s lower atmosphere.

“Watching the waves move upwards tells us a lot about the properties of the atmosphere above sunspots – like temperature, pressure, and density,” said Ruizhu Chen, a graduate student scientist at Stanford who is an author on the study. “More importantly, we can figure out the magnetic field strength and direction.”


Images above: Scientists used data from NASA’s Solar Dynamics Observatory, NASA’s Interface Region Imaging Spectrograph, and the Big Bear Solar Observatory to track a solar wave as it channeled upwards from the sun’s surface into the atmosphere. Image Credits: Zhao et al/NASA/SDO/IRIS/BBSO.

The effect of the magnetic field on these waves is pronounced. Instead of traveling straight upwards through the sun, the waves veer off, taking a curved path through the atmosphere.

“The magnetic field is acting like railroad tracks, guiding the waves as they move up through the atmosphere,” said Pesnell, who was not involved in this study.

The second implication of this new research is for a long-standing question in solar physics – the coronal heating problem.

The sun produces energy by fusing hydrogen at its core, so the simplest models suggest that each layer of the sun should be cooler as you move outward. However, the sun’s atmosphere, called the corona, is about a hundred times hotter than the region below – counter to what you would expect.

No one has as-yet been able to definitively pinpoint the source of all the extra heat in the corona, but these waves may play a small role.

Interface Region Imaging Spectrograph (IRIS). Image Credit: NASA

“When a wave travels upwards, a number of different things can happen,” said Zhao. “Some may reflect back downwards, or contribute to heating – but by how much, we don’t yet know.”

NASA Goddard built, operates and manages the SDO spacecraft for NASA's Science Mission Directorate in Washington. Lockheed Martin designed the IRIS observatory and manages the mission for NASA. The Big Bear Solar Observatory is operated by the New Jersey Institute of Technology in Newark, New Jersey.

Related links:

The Astrophysical Journal Letters: http://iopscience.iop.org/article/10.3847/2041-8205/830/1/L17

NASA’s SDO website: https://www.nasa.gov/mission_pages/sdo/main/index.html

NASA’s IRIS website: http://www.nasa.gov/mission_pages/iris/index.html

Images (mentioned), Animation (mentioned), Text, Credits: NASA’s Goddard Space Flight Center, by Sarah Frazier/Karl Hille.

Greetings, Orbiter.ch

Astronauts Relaxing Ahead of Crew and Cargo Arrivals










ISS - Expedition 49 Mission patch.

October 20, 2016

Astronauts Kate Rubins and Takuya Onishi are having a light day today ahead of the arrival of three new crewmates Friday morning. The duo also is waiting for Sunday morning’s cargo delivery aboard the Cygnus resupply ship.

NASA TV will broadcast the Soyuz MS-02 space ship docking to the International Space Station beginning Friday at 5:15 a.m. EDT. NASA astronaut Shane Kimbrough and cosmonauts Sergey Ryzhikov and Andrey Borisenko will dock to the Poisk module, beginning their Expedition 49-50 mission which will last until February.


Image above: Western Europe is pictured at night by an Expedition 49 crew member. Image Credit: NASA.

Two days later on Sunday morning, the Cygnus resupply craft from Orbital ATK will arrive with more than 5,100 pounds of cargo, including gear to support dozens of science investigations. Onishi and Rubins will be stationed in the cupola at the controls of the Canadarm2 robotic arm to grapple Cygnus following its journey to the complex.

To learn more about the International Space Station, visit: http://www.nasa.gov/station.

Check out the NASA TV schedule online for information on how to watch live and replays:
http://www.nasa.gov/ntv

Image (mentioned), Text, Credits: NASA/Mark Garcia.

Greetings, Orbiter.ch

Cassini Sees Dramatic Seasonal Changes on Titan












NASA - Cassini Mission to Saturn patch.

Oct. 20, 2016


Image above: Slipping into shadow, the south polar vortex at Saturn's moon Titan still stands out against the orange and blue haze layers that are characteristic of Titan's atmosphere. Images like this, from NASA's Cassini spacecraft, lead scientists to conclude that the polar vortex clouds form at a much higher altitude -- where sunlight can still reach -- than the lower-altitude surrounding haze. Image Credits: NASA/JPL-Caltech/Space Science Institute.

As southern winter solstice approaches in the Saturn system, NASA's Cassini spacecraft has been revealing dramatic seasonal changes in the atmospheric temperature and composition of Saturn's largest moon, Titan.

Winter is taking a grip on Titan's southern hemisphere, and a strong, whirling atmospheric circulation pattern -- a vortex -- has developed in the upper atmosphere over the south pole. Cassini has observed that this vortex is enriched in trace gases -- gases that are otherwise quite rare in Titan's atmosphere. Cassini's observations show a reversal in the atmosphere above Titan's poles since the spacecraft arrived at Saturn in 2004, when similar features were seen in the northern hemisphere.

"Cassini’s long mission and frequent visits to Titan have allowed us to observe the pattern of seasonal changes on Titan, in exquisite detail, for the first time," said Athena Coustenis, a member of Cassini's Composite Infrared Spectrometer team at the Observatoire de Paris. Coustenis is presenting the team's findings at the joint 48th meeting of the American Astronomical Society Division for Planetary Sciences and 11th European Planetary Science Congress (EPSC), this week in Pasadena, California. "We arrived at the northern mid-winter and have now had the opportunity to monitor Titan's atmospheric response through two full seasons."

Heat is circulated through Titan's atmosphere via a pole-to-pole cycle of warm gases upwelling at the summer pole and cold gases subsiding at the winter pole. Cassini's observations have shown a large-scale reversal of this system, beginning immediately after the equinox in 2009.

Titan's hemispheres have responded in different ways to these seasonal changes. The wintry effects have led to a temperature drop of 72 degrees Farenheit (40 degrees Celsius) in the southern polar stratosphere over the last four years. This contrasts with a much more gradual warming in the northern hemisphere, where temperatures remained stable during the early spring and have shown just a six-degree increase since 2014.

Artist's view of Cassini spacecraft Titan flyby. Image Credits: NASA/JPL-Caltech

Within months following the equinox, the vortex in the stratosphere over the south pole had become prominent, as had an atmospheric "hot spot" at high altitudes. The corresponding features in the northern hemisphere had almost disappeared by 2011.

Inside the polar vortex over the increasingly shadowed south pole, there has been a rapid build-up of trace gases that accumulate in the absence of ultraviolet sunlight. These include complex hydrocarbons previously only seen at high northern latitudes.

A more detailed version of this story is available from the EPSC meeting website:

http://www.europlanet-eu.org/titan-experiences-dramatic-seasonal-changes

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org and ESA's website http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Preston Dyches/EPSC Press Office/Anita Heward.

Greetings, Orbiter.ch

Weekly Recap From the Expedition Lead Scientist, Week of Oct. 10, 2016










ISS - Expedition 49 Mission patch.

Oct. 20, 2016

(Highlights: Week of Oct. 10, 2016) - Crew members on the International Space Station completed more human research investigations in advance of their return home at the end of the month, working to improve the health of future space travelers and residents on Earth.

Two crew members spent time tracking how fluids move around the human body in microgravity. NASA astronaut Kate Rubins assisted JAXA (Japan Aerospace Exploration Agency) astronaut Takuya Onishi with ultrasounds and measurements for the study Fluid Shifts Before, During, and After Prolonged Space Flight and Their Association with Intracranial Pressure and Visual Impairment (Fluid Shifts).


Image above: NASA astronaut Kate Rubins is seen in the window of the Cupola on the International Space Station with the Bigelow Expandable Activity Module (BEAM) in the foreground. Image Credit: NASA.

One of the main risks for humans during long-duration space missions is change in vision. More than half of American astronauts experience vision changes and other physical alterations to parts of their eyes during and after long-duration spaceflight. It is hypothesized that the fluid shift toward the head that occurs during spaceflight leads to increased pressure in the brain, which may push on the back of the eye, causing it to change shape. Fluid Shifts measures how much fluid shifts from the lower body to the upper body, in or out of cells and blood vessels, and determines the impact these shifts have on fluid pressure in the head, changes in vision and eye structures.

Scientists want to develop preventive measures against these and other physiological changes during spaceflight. Results from the Fluid Shifts investigation also may improve understanding of how blood pressure in the brain specifically affects eye shape and vision, which could benefit people confined to long-term bed rest, or suffering from disease states that increase swelling and pressure in the brain.

Onishi completed ultrasound scans for the Cardiac and Vessel Structure and Function with Long-Duration Space Flight and Recovery (Vascular Echo) study. The Canadian Space Agency (CSA) investigation examines the changes in blood vessels and the heart while crew members are in space and follows their recovery after returning to Earth.


Image above: NASA astronaut Kate Rubins takes surface samples as part of the Microbe IV investigation that monitors for germs and bacteria on the orbiting laboratory. Monitoring microbes that can cause illness is crucial for maintaining crew health and the sampling devices can be used to develop cleaner work environments in space and on Earth. Image Credit: NASA.

As humans get older on Earth, arteries can stiffen and cause an increase in blood pressure, elevating the risk of heart disease. Physicians have observed that crew members returning from the space station also have much stiffer arteries than before they went into space. The Vascular Echo investigation will give researchers a better understanding of the changes in the cardiovascular system, which may provide insight into potential countermeasures to maintain health in space and on Earth.

Rubins collected samples around the station for the Microbe-IV investigation which involves gathering samples and monitoring for germs and bacteria on the orbiting laboratory. Monitoring microbes that can cause illness is crucial for maintaining crew members' health.

The Japan Aerospace Exploration Agency (JAXA)-led investigation uses several passive devices to capture and sample microbes, such as bacteria and fungus, on the orbiting laboratory. The sampling devices are frozen and returned to Earth, where researchers and students count and classify the microbes. Sampling the microbial environment on the space station helps scientists monitor the station's air purity. The sampling devices for Microbe-IV can be used to develop cleaner work environments in space and on Earth. Procedures for monitoring and counting microbe populations could enable new microbe control standards for the pharmaceutical and food processing industries.


Image above: Russian cosmonaut Anatoly Ivanishin works on the Plasma Kristall-4 experiment, a scientific collaboration between the European Space Agency (ESA) and the Russian Federal Space Agency (Roscosmos), performing research in the field of "Complex Plasmas." Image Credit: NASA.

Progress was made on other investigations and facilities this week, including ISS Ham, JAXA EPO, ACE T-1, DOSIS-3D, Meteor, WetLab-2, Personal CO2 Monitors, SPHERES-SLOSH, Cell Biology Experiment Facility, and Manufacturing Device.

Other human research investigations conducted this week include Biological Rhythms-48, Biochem Profile, Cardio Ox, Repository, Body Measures, Dose Tracker, Fine Motor Skills, Habitability, Marrow, and Space Headaches.

Related links:

Fluid Shifts: http://www.nasa.gov/mission_pages/station/research/experiments/1257.html

Vascular Echo: http://www.nasa.gov/mission_pages/station/research/experiments/1921.html

Microbe-IV: http://www.nasa.gov/mission_pages/station/research/experiments/1300.html

ISS Ham: http://www.nasa.gov/mission_pages/station/research/experiments/346.html

ACE T-1: http://www.nasa.gov/mission_pages/station/research/experiments/2033.html

DOSIS-3D: http://www.nasa.gov/mission_pages/station/research/experiments/184.html

Meteor: http://www.nasa.gov/mission_pages/station/research/experiments/1323.html

WetLab-2: http://www.nasa.gov/ames/research/space-biosciences/wetlab-2

Personal CO2 Monitors: http://www.nasa.gov/mission_pages/station/research/experiments/2101.html

SPHERES-SLOSH: http://www.nasa.gov/mission_pages/station/research/experiments/980.html

Cell Biology Experiment Facility: http://www.nasa.gov/mission_pages/station/research/experiments/CBEF.html

Manufacturing Device: http://www.nasa.gov/mission_pages/station/research/experiments/2198.html

Biological Rhythms-48: http://www.nasa.gov/mission_pages/station/research/experiments/868.html

Biochem Profile: http://www.nasa.gov/mission_pages/station/research/experiments/1008.html

Cardio Ox: http://www.nasa.gov/mission_pages/station/research/experiments/931.html

Repository: http://www.nasa.gov/mission_pages/station/research/experiments/981.html

Body Measures: http://www.nasa.gov/mission_pages/station/research/experiments/1070.html

Dose Tracker: http://www.nasa.gov/mission_pages/station/research/experiments/1933.html

Fine Motor Skills: http://www.nasa.gov/mission_pages/station/research/experiments/1767.html

Habitability: http://www.nasa.gov/mission_pages/station/research/experiments/1772.html

Marrow: http://www.nasa.gov/mission_pages/station/research/experiments/1931.html

Space Headaches: http://www.nasa.gov/mission_pages/station/research/experiments/181.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Japan Aerospace Exploration Agency (JAXA): http://global.jaxa.jp/

Canadian Space Agency (CSA): http://www.asc-csa.gc.ca/eng/

Images (mentioned), Text, Credits: NASA/John Love, Acting Lead Increment Scientist Expeditions 49 & 50/Jennifer Harbaugh.

Best regards, Orbiter.ch

Citizen Scientists Seek South Pole 'Spiders' on Mars












NASA - Mars Reconnaissance Orbiter (MRO) patch.

Oct. 20, 2016


Image above: This image shows spidery channels eroded into Martian ground. It is a Sept. 12, 2016, example from HiRISE camera high-resolution observations of more than 20 places that were chosen in 2016 on the basis of about 10,000 volunteers' examination of Context Camera lower-resolution views of larger areas. Image Credits: NASA/JPL-Caltech/Univ. of Arizona.

Ten thousand volunteers viewing images of Martian south polar regions have helped identify targets for closer inspection, yielding new insights about seasonal slabs of frozen carbon dioxide and erosional features known as "spiders."

From the comfort of home, the volunteers have been exploring the surface of Mars by reviewing images from the Context Camera (CTX) on NASA's Mars Reconnaissance Orbiter and identifying certain types of seasonal terrains near Mars' south pole. These efforts by volunteers using the "Planet Four: Terrains" website have aided scientists who plan observations with the same orbiter's High Resolution Imaging Science Experiment (HiRISE) camera. HiRISE photographs much less ground but in much greater detail than CTX.

Volunteers have helped identify more than 20 regions in mid-resolution images to investigate with higher resolution. "It's heartwarming to see so many citizens of planet Earth donate their time to help study Mars," said HiRISE Deputy Principal Investigator Candice Hansen, of the Planetary Science Institute, Tucson, Arizona. "Thanks to the discovery power of so many people, we're using HiRISE to take images of places we might not have studied without this assistance."

Planetary scientist Meg Schwamb, of the Gemini Observatory, Hilo, Hawaii, presented results from the first year of this citizen science project Thursday at the annual meeting of the American Astronomical Society's Division for Planetary Sciences and the European Planetary Science Congress, in Pasadena, California.

The type of terrain called spiders, or "araneiform" (from the Latin word for spiders), is characterized by multiple channels converging at a point, resembling a spider's long legs. Previous studies concluded that this ground texture results from extensive sheets of ice thawing bottom-side first as the ice is warmed by the ground below it. Thawed carbon dioxide gas builds up pressure, and the gas escapes through vents in the overlying sheet of remaining ice, pulling dust with it. This process carves the channels that resemble legs of a spider.

"The trapped carbon dioxide gas that carves the spiders in the ground also breaks through the thawing ice sheet," Schwamb said. "It lofts dust and dirt that local winds then sculpt into hundreds of thousands of dark fans that are observed from orbit. For the past decade, HiRISE has been monitoring this process on other parts of the south pole. The 20 new regions have been added to this seasonal monitoring campaign. Without the efforts of the public, we wouldn't be able to see how these regions evolve over the spring and summer compared with other regions." 

Mars Reconnaissance Orbiter (MRO) spacecraft. Image Credits: NASA/JPL-Caltech

Some of the HiRISE observations guided by the volunteers' input confirmed "spider" terrain in areas not previously associated with carbon dioxide slab ice.

"From what we've learned about spider terrain elsewhere, slab ice must be involved at the locations of these new observations, even though we had no previous indication of it there," Hansen said. "Maybe it's related to the erodability of the terrain."

Some of the new observations targeted with information from the volunteers confirm spiders in areas where the ground surface is made of material ejected from impact craters, blanketing an older surface. "Crater ejecta blankets are erodible. Perhaps on surfaces that are more erodable, relative to other surfaces, slab ice would not need to be present as long, or as thick, for spiders to form," Hansen said. "We have new findings, and new questions to answer, thanks to all the help from volunteers."

The productive volunteer participation continues, and new CTX images have been added for examining additional areas in Mars' south polar region. Planet Four: Terrains is on a platform released by the Zooniverse, which hosts 48 projects that enlist people worldwide to contribute to discoveries in fields ranging from astronomy to zoology. For information about how to participate, visit: http://terrains.planetfour.org

With CTX, HiRISE and four other instruments, the Mars Reconnaissance Orbiter has been investigating Mars since 2006.

Malin Space Science Systems, San Diego, built and operates CTX. The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp. of Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter and collaborates with JPL to operate it. For additional information about the project, visit: http://mars.nasa.gov/mro

Images (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/Tony Greicius/JPL/Guy Webster/Planetary Science Institute/Alan Fischer/Gemini Observatory/Peter Michaud.

Greetings, Orbiter.ch