samedi 14 décembre 2013

China's Jade Rabbit rover rolls on to Moon's surface










CNSA - China National Space Administration logo.

Dec. 14, 2013

China's Jade Rabbit robot rover has driven off its landing module and on to the Moon's surface.

The robotic vehicle rolled down a ramp lowered by the lander and on to the volcanic plain known as Sinus Iridum.

Earlier on Saturday, the landing module containing the rover fired its thrusters to perform the first soft landing on the Moon since 1976.


Image above: The Jade Rabbit, seen in this artist's impression, is the first wheeled vehicle on the Moon since the 1970s. Image Credit: CNSA.

The touchdown in the Moon's northern hemisphere marks the latest step in China's ambitious space programme.

The lander will operate there for a year, while the rover is expected to work for some three months.

The Chang'e-3 mission landed some 12 days after being launched atop a Chinese-developed Long March 3B rocket from Xichang in the country's south.

video
China Probe Lands On The Moon

The official Xinhua news service reported that the craft began its descent just after 1300 GMT (2100 Beijing time), touching down in Sinus Iridum (the Bay of Rainbows) 11 minutes later.

"I was lucky enough to see a prototype rover in Shanghai a few years ago - it's a wonderful technological achievement to have landed," Prof Andrew Coates, from UCL's Mullard Space Science Laboratory, told BBC News.

Chang'e-3 is the third unmanned rover mission to touch down on the lunar surface, and the first to go there in more than 40 years. The last was an 840kg (1,900lb) Soviet vehicle known as Lunokhod-2, which was kept warm by polonium-210.

But the six-wheeled Chinese vehicle carries a more sophisticated payload, including ground-penetrating radar which will gather measurements of the lunar soil and crust.

China Moon Mission description. Image Credit: AFP

Its name - chosen in an online poll of 3.4 million voters - derives from an ancient Chinese myth about a rabbit living on the moon as the pet of the lunar goddess Chang'e.

The rover and lander are powered by solar panels but some sources suggest they also carry radioisotope heating units (RHUs), containing plutonium-238 to keep them warm during the cold lunar night.

Reports suggest the lander and rover will photograph each other at some point on Sunday.

According to Chinese space scientists, the mission is designed to test new technologies, gather scientific data and build intellectual expertise. It will also scout valuable mineral resources that could one day be mined.

video
China's Yutu  Jade Rabbit Lunar Rover lands on Moon

"China's lunar programme is an important component of mankind's activities to explore [the] peaceful use of space," Sun Huixian, a space engineer with the Chinese lunar programme, told Xinhua.

After this, a mission to bring samples of lunar soil back to Earth is planned for 2017. And this may set the stage for further robotic missions, and - perhaps - a crewed lunar mission in the 2020s.

Dean Cheng, a senior research fellow at the Heritage Foundation, a conservative think-tank in Washington DC, said China's space programme was a good fit with China's concept of "comprehensive national power". This might be described as a measure of a state's all-round capabilities.


Image above: The rover will be exploring a flat volcanic plain known as Sinus Iridum (the Bay of Rainbows). Image Credit: AP.

But he said that China did not see itself as being in a "space race" with anyone else. "I'm comparing it specifically to how the US and the Soviets were behaving in the late 1950s and 1960s when you had space launches almost every month.

"Look at how often the Chinese do manned missions - it's almost every other year."

Instead, the country is methodically and patiently building up the key elements needed for an advanced space programme - from launchers to manned missions in Earth orbit to unmanned planetary craft - and it is investing heavily.

Mr Cheng added: "China is saying: 'We are doing something that only two other countries have done before - the US and the Soviet Union."

The landing site of Sinus Iridum (Latin for Bay of Rainbows) is a flat volcanic plain, part of a larger feature known as Mare Imbrium that forms the right eye of the "Man in the Moon".

For more information about China National Space Administration (CNSA), visit: http://www.cnsa.gov.cn/n615709/cindex.html

Images, Videos, Text, Credits: CNSA / AP / AFP / BBC News / Paul Rincon.

Best regards, Orbiter.ch

Cooling System Troubleshooting, Biomedical Research on Station












ISS - International Space Station patch.

Dec. 14, 2013

While the ground team continues troubleshooting an issue with one of the International Space Station’s two external cooling loops Friday, the Expedition 38 crew focused on biomedical research and preparations for the robotic capture of a commercial cargo craft.

Overnight, flight controllers attempted to power cycle the starboard truss pump module in an attempt to fix the incorrect positioning of the module’s flow control valve that caused the pump to malfunction Wednesday. The attempt was unsuccessful. The engineering teams have concluded there is no way to modify the valve’s firmware so that the valve can be commanded outside of its firmware limits.  There is still additional work to be done in understanding if the thermal loop can be warmed by other methods, which could include manipulating other valves in the system or adding heat to the system via heaters.


Image above: Flight Engineer Koichi Wakata performs maintenance on the Advanced Biological Research System hardware. Image Credit: NASA TV.

Learn more about the station's cooling system: http://www.nasa.gov/content/cooling-system-keeps-space-station-safe-productive/

While the engineering evaluations continue, station program managers will have further discussions on potential contingency spacewalk planning that could result in multiple spacewalks to replace the pump module beginning as early as late next week.


Image above: This graphic shows the location of the International Space Station's starboard pump module. Image Credit: NASA.

With the station currently in a stable configuration, the six astronauts and cosmonauts on board focused on science and robotics and prepared for a planned Russian spacewalk.

Commander Oleg Kotov and Flight Engineer Sergey Ryazanskiy conducted a preliminary review of a spacewalk they will perform on Dec. 27. During that excursion, the two cosmonauts will install high and medium resolution cameras on a platform outside the Russian segment of the station, attach a foot restraint for future spacewalking tasks and remove and replace several experiment packages.


Image above: Flight Engineer Rick Mastracchio performs routine in-flight maintenance in the Columbus laboratory of the International Space Station. Image Credit: NASA.

At the controls of the robotic workstation inside the station’s cupola, Flight Engineers Mike Hopkins and Koichi Wakata rehearsed grapple procedures for the upcoming capture of Orbital Sciences’ Cygnus cargo ship on its first commercial resupply mission.  For Friday’s practice session, the two astronauts practiced the techniques they will use to capture Cygnus with the station’s 57-foot robotic arm, Canadarm2, if the vehicle is in a misaligned position. Cygnus is still scheduled to launch Wednesday from Wallops Flight Facility in Virginia and rendezvous with the station on Dec. 21. Mission managers have deferred the final decision on whether to proceed with or postpone the launch of Cygnus until more is known about the station’s flow control valve issue.

Wakata and Flight Engineer Rick Mastracchio removed and replaced an assembly inside the Advanced Biological Research System, or ABRS, a research facility with two independently-controlled chambers that can grow plants, microorganisms and small arthropods.

Read more about ABRS: http://www.nasa.gov/mission_pages/station/research/experiments/ABRS.html

Afterward, Mastracchio assisted Hopkins with the Body Measures experiment, which collects anthropometric data to help researchers understand the magnitude and variability of the changes to body measurements during spaceflight. Predicting these changes will maximize crew performance, prevent injury and reduce time spent altering or adjusting suits and workstations to accommodate anthropometrics. 

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

Mastracchio took a break from his work to talk with Marcia Dunn of the Associated Press and SPACE.com’s Tariq Malik, answering questions about the loss of the cooling loop and the research taking place aboard the complex.

video
 Space Station Crewmember Discusses Life in Space with News Media

Video above: Flight Engineer Rick Mastracchio talks with reporters from the Associated Press and SPACE.com. Video Credit: NASA TV.

Wakata and Hopkins rounded out their day with the Reversible Figures experiment, which tracks how the adaptation of an astronaut’s neurovestibular system to weightlessness may alter 3-D visual perception.

Read more about Reversible Figures: http://www.nasa.gov/mission_pages/station/research/experiments/971.html

Flight Engineer Mikhail Tyurin performed the Uragan Earth-observation experiment, which seeks to document and predict the development of natural and man-made disasters on Earth. Afterward he conducted routine maintenance on the life support systems in the Zvezda service module.

The thrusters of the ISS Progress 53 cargo ship docked to aft port of Zvezda were fired at 9:57 a.m. EST for the second of two reboosts of the station to set up the correct phasing for Russian visiting vehicle operations next year and to modify the phasing capability for Cygnus for two-day rendezvous attempts in December. The first reboost in this series, a 7-minute, 41-second burn by Progress 53, took place Wednesday.

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/

Images (mentioned), Video (mentioned), Text, Credit: NASA.

Greetings, Orbiter.ch

vendredi 13 décembre 2013

Surprise Picture for WISE's Fourth Anniversary










NASA - Wide-Field Infrared Survey Explorer logo.

Dec. 13, 2013

 March of Asteroids Across Dying Star

Image above: A dying star, called the Helix nebula, is shown surrounded by the tracks of asteroids in an image captured by NASA's Wide-field Infrared Survey Explorer, or WISE. Image Credit: NASA/JPL-Caltech/UCLA.

In an unexpected juxtaposition of cosmic objects that are actually quite far from each other, a newly released image from NASA's Wide-Field Infrared Survey Explorer (WISE) shows a dying star, called the Helix nebula, surrounded by the tracks of asteroids. The nebula is far outside our solar system, while the asteroid tracks are inside our solar system.

The portrait, discovered by chance in a search for asteroids, comes at a time when the mission's team is celebrating its fourth launch anniversary -- and new lease on life. In August, NASA decided to bring WISE out of hibernation to search for more asteroids. The mission was rechristened NEOWISE, formerly the name of the asteroid-hunting portion of WISE.

"I was recently looking for asteroids in images collected in 2010, and this picture jumped out at me," said Amy Mainzer, the NEOWISE principal investigator at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "I recognized the Helix nebula right away."

WISE launched into the morning skies above Vandenberg Air Force Base in central California on Dec. 14, 2009. By early 2011, it had finished scanning the entire sky twice in infrared light, snapping pictures of nearly one billion objects, including remote galaxies, stars and asteroids. Upon completing its main goals, WISE was put to sleep. Now, engineers are bringing the spacecraft out of slumber, as it cools back down to the chilly temperatures required for infrared observations. The spacecraft no longer has onboard coolant, but two of its infrared channels still work and can be used for asteroid hunting.

NASA's Wide-Field Infrared Survey Explorer (WISE). Image Credit: NASA/JPL-Caltech

"WISE is the spacecraft that keeps on giving," said Ned Wright of UCLA, the principal investigator of WISE before it transitioned into NEOWISE.

In the Helix nebula image, infrared wavelengths of light have been assigned different colors, with longer wavelengths being red, and shorter, blue. The bluish-green and red materials are expelled remnants of what was once a star similar to our sun. As the star aged, it puffed up and its outer layers sloughed off. The burnt-out core of the star, called a white dwarf, is heating the expelled material, inducing it to glow with infrared light. Over time, the brilliant object, known as a planetary nebula, will fade away, leaving just the white dwarf.

Skirting around the edges of the Helix nebula are the footprints of asteroids marching across the field of view. Each set of yellow dots is a series of pictures of an asteroid. As the asteroid moved, WISE snapped several pictures, all of which are represented in this view. Scientists use these data to discover and characterize asteroids, including those that pass relatively close to Earth, called near-Earth asteroids. Infrared data are particularly useful for finding the smaller, darker asteroids that are more difficult to see with visible light, and for measuring the asteroids’ sizes.

The other streaks in the picture are Earth-orbiting satellites and cosmic rays.

JPL manages and operates NEOWISE for NASA's Science Mission Directorate. The WISE mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://neowise.ipac.caltech.edu, http://www.nasa.gov/wise and http://wise.astro.ucla.edu

Images (mentioned), Text, Credits: NASA / JPL / Whitney Clavin.

Cheers, Orbiter.ch

Herschel spies active argon in Crab Nebula












ESA - Herschel Mission patch.

13 December 2013

Using ESA's Herschel Space Observatory, a team of astronomers has found first evidence of a noble-gas based molecule in space. A compound of argon, the molecule was detected in the gaseous filaments of the Crab Nebula, one of the most famous supernova remnants in our Galaxy. While argon is a product of supernova explosions, the formation and survival of argon-based molecules in the harsh environment of a supernova remnant is an unforeseen surprise.


Just like a group of people, the periodic table of chemical elements has its share of team players and loners. While some elements tend to react more easily with other species, forming molecules and other compounds, others hardly ever take part in chemical reactions and are mainly found in isolation. 'Inert' elements par excellence are the noble gases: helium, neon, argon, krypton, xenon and radon.


Image above: Herschel image and spectrum of the Crab Nebula, with emission lines from the molecular ion argon hydride. Credit: ESA/Herschel/PACS, SPIRE/MESS Key Programme Supernova Remnant Team.

The name of one of them – argon – derives from the Greek word for idle, to emphasise its highly inert nature. But noble gases are not entirely inactive. While at first scientists doubted that chemical compounds could even contain noble gases, several such species are now known and have been extensively studied in the laboratory.


Things are more complex in space. Over the decades, astronomers have detected atoms and ions of noble gases in a variety of cosmic environments, ranging from the Solar System to the atmospheres of stars, from dense nebulae to the diffuse interstellar medium. But the search for noble-gas based compounds had until now proved unsuccessful, suggesting that these almost inert elements might have a hard time reacting with other species in space.

A new study, led by Michael Barlow from University College London, UK, and based on data from ESA's Herschel Space Observatory, has found the first evidence of such a compound in space. The results are published in the journal Science.

The team of astronomers has detected emission from argon hydride (ArH+), a molecular ion containing the noble gas argon, in the Crab Nebula. A wispy and filamentary cloud of gas and dust, the Crab Nebula is the remnant of a supernova explosion that was observed by Chinese astronomers in the year 1054.

"At first, the discovery seemed bizarre," comments Barlow.

"With hot gas still expanding at high speeds after the explosion, a supernova remnant is a harsh, hostile environment, and one of the places where we least expected to find a noble-gas based molecule," he adds.


Image above: Herschel (red) and Hubble (blue) composite image of the Crab Nebula. Credit: ESA/Herschel/PACS/MESS Key Programme Supernova Remnant Team; NASA, ESA and Allison Loll/Jeff Hester (Arizona State University).

Argon hydride is produced when ions of argon (Ar+) react with hydrogen molecules (H2), but these two species are usually found in different regions of a nebula. While ions form in the most energetic regions, where radiation from a star or stellar remnant ionises the gas, molecules take shape in the denser, colder pockets of gas that are shielded from this powerful radiation.


"But we soon realised that even in the Crab Nebula, there are places where the conditions are just right for a noble gas to react and combine with other elements.

"There, in the transition regions between ionised and molecular gas, argon hydride can form and survive," explains Barlow.

This new picture was supported by the comparison of the Herschel data with observations of the Crab Nebula performed at other wavelengths, which revealed that the regions where they had found ArH+ also exhibit higher concentrations of both Ar+ and H2. There, argon ions can react with hydrogen molecules forming argon hydride and atomic hydrogen.

In the partly ionised gas filling these regions, molecules collide frequently with ions and free electrons. These collisions excite the molecular structure of ArH+ making it rotate; in turn, molecular rotations produce the emission features detected in the spectrum of the Crab Nebula by Herschel.
"The discovery was truly serendipitous: we were observing the Crab Nebula to study its dust content. But then, on top of the emission from dust, we found two emission lines that had never been seen before," says co-author Bruce Swinyard, also from University College London.

The identification of these lines was a challenging task. To this end, the astronomers exploited two extensive databases of molecular spectra and, after lengthy investigation, they matched the observed features with two characteristic lines emitted by ArH+.

"And there's icing on the cake: from a molecule's emission, we can determine the isotope of the elements that form it – something that we can't do when we see only ions," adds Swinyard.
The Herschel data indicate that the argon hydride found in the Crab Nebula is made up of the argon isotope 36Ar. This is the first time that astronomers could identify the isotopic nature of an element in a supernova remnant.

 
Image above:  Artist's view of the Herschel Space Observatory. Image credit: ESA / NASA.

"Finding that argon in the Crab Nebula consists of 36Ar was not surprising because this is the dominant isotope of argon across the Universe.

"And it's also the main argon isotope to be synthesised in the nuclear reactions during supernova explosions, so its detection in the Crab Nebula confirms that this iconic nebula was created by the explosive death of a massive star," explains Barlow.

The astronomers are planning further observations with other facilities to seek new emission lines in the Crab Nebula's spectrum, possibly from molecules containing different isotopes of argon. The detection of such a molecule would enable them to study the ratio of different isotopes produced by supernovae and to learn more about the nuclear reactions that take place when a massive star dies.
"This is not only the first detection of a noble-gas based molecule in space, but also a new perspective on the Crab Nebula. Herschel has directly measured the argon isotope we expect to be produced via explosive nucleosynthesis in a core-collapse supernova, refining our understanding of the origin of this supernova remnant," concludes Göran Pilbratt, Herschel Project Scientist at ESA.


Background information

 

The results described in this article are reported in "Detection of a Noble Gas Molecular Ion, 36ArH+, in the Crab Nebula", by M. J. Barlow et al., published in Science, 342, 6163, 1343-1345, 13 December 2013. DOI: 10.1126/science.124358213.

The argon isotope found in the Crab Nebula is different from the one that dominates in Earth's atmosphere, 40Ar, which derives from the decay of a radioactive isotope of potassium (40K) present in our planet's rocks. At almost one per cent, argon is the third most abundant gas in the atmosphere of Earth after nitrogen and oxygen, and was discovered at the end of the 19th century.

The study is based on data collected with the Spectral and Photometric Imaging Receiver (SPIRE) on board ESA's Herschel Space Observatory. The team of astronomers detected two emission lines corresponding to the first two rotational transitions of argon hydride (ArH+) at frequencies of 617.5 GHz and 1234.6 GHz, respectively. To identify the lines, they made use of two extensive databases of molecular lines: the Cologne Database for Molecular Spectroscopy (CDMS) and the Madrid Molecular Spectroscopy Excitation (MADEX) code.

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

The SPIRE instrument contains an imaging photometer (camera) and an imaging spectrometer. The camera operates in three wavelength bands centred on 250, 350 and 500 µm, and so can make images of the sky simultaneously in three sub-millimetre colours; the spectrometer covers the wavelength range between 194 and 671 μm. SPIRE has been developed by a consortium of institutes led by Cardiff Univ. (UK) and including Univ. Lethbridge (Canada); NAOC (China); CEA, LAM (France); IFSI, Univ. Padua (Italy); IAC (Spain); Stockholm Observatory (Sweden); Imperial College London, RAL, UCL-MSSL, UKATC, Univ. Sussex (UK); Caltech, JPL, NHSC, Univ. Colorado (USA). This development has been supported by national funding agencies: CSA (Canada); NAOC (China); CEA, CNES, CNRS (France); ASI (Italy); MCINN (Spain); SNSB (Sweden); STFC, UKSA  (UK); and NASA (USA).

Herschel was launched on 14 May 2009 and completed science observations on 29 April 2013.

Related Publications:

Barlow, M., et al. [2013]: http://sci.esa.int/herschel/object/index.cfm?fobjectid=53333

Mission:

Show All Missions: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=51459

Images (mentioned), Text, Credits: ESA / Herschel Project Scientist, Göran Pilbratt / Department of Physics & Astronomy University College London, Bruce M. Swinyard / Department of Physics & Astronomy University College London, Michael J. Barlow.

Greetings, Orbiter.ch



jeudi 12 décembre 2013

The correction of the ISS orbit














ISS - International Space Station patch / ROSCOSMOS - Russian Vehicles patch.

12/12/2013

December 11, 2013 held a test correction orbit of the International Space Station.

According to calculations by the ballistic and navigation support Mission Control Center FSUE TsNIIMash engines cargo spacecraft Progress M-21M were included in the 20 hours 34 minutes Moscow time and worked 459 seconds.

ISS reboost by Progress cargo vehicle

As a result, ISS received increment speed of 1 m / s. The average height of its orbit by 1.7 km and reached 415.4 km.

According to the service ballistic and navigation support MCC after the ISS orbit maneuver parameters were as follows:

- Minimum height - 415.6 km
- Maximum height - 432.2 km
- Period - 92.819 min
- Inclination - 51,67 °

International Space Station (ISS)

ROSCOSMOS Press Release: http://www.federalspace.ru/20052/

Images, Text, Credits: Roscosmos press service and PCO / NASA / Translation: Orbiter.ch Aerospace.

Приветствия, Greetings, Orbiter.ch

NASA's / ESA's Cassini Spacecraft Reveals Clues About Saturn Moon












NASA / ESA - Cassini-Huygens Mission to Saturn & Titan patch.

Dec. 12, 2013

video
 Soaring Over Titan: Extraterrestrial Land of Lakes

Video above: This colorized flyover movie from NASA's Cassini mission takes viewers over the two largest seas on Saturn's moon Titan and nearby lakes.

NASA's Cassini spacecraft is providing scientists with key clues about Saturn's moon Titan, and in particular, its hydrocarbon lakes and seas.

Titan is one of the most Earth-like places in the solar system, and the only place other than our planet that has stable liquid on its surface.

Cassini's recent close flybys are bringing into sharper focus a region in Titan's northern hemisphere that sparkles with almost all of the moon's seas and lakes. Scientists working with the spacecraft's radar instrument have put together the most detailed multi-image mosaic of that region to date. The image includes all the seas and most of the major lakes. Some of the flybys tracked over areas that previously were seen at a different angle, so researchers have been able to create a flyover of the area around Titan's largest and second largest seas, known as Kraken Mare and Ligeia Mare, respectively, and some of the nearby lakes.

"Learning about surface features like lakes and seas helps us to understand how Titan's liquids, solids and gases interact to make it so Earth-like," said Steve Wall, acting radar team lead at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "While these two worlds aren't exactly the same, it shows us more and more Earth-like processes as we get new views."

Titan's North

Image above: This colorized mosaic from NASA's Cassini mission shows the most complete view yet of Titan's northern land of lakes and seas. Saturn's moon Titan is the only world in our solar system other than Earth that has stable liquid on its surface. Image Credit: NASA/JPL-Caltech/ASI/USGS.

These new images show Kraken Mare is more extensive and complex than previously thought. They also show nearly all of the lakes on Titan fall into an area covering about 600 miles by 1,100 miles (900 kilometers by 1,800 kilometers). Only 3 percent of the liquid at Titan falls outside of this area.

"Scientists have been wondering why Titan's lakes are where they are. These images show us that the bedrock and geology must be creating a particularly inviting environment for lakes in this box," said Randolph Kirk, a Cassini radar team member at the U.S. Geological Survey in Flagstaff, Ariz. "We think it may be something like the formation of the prehistoric lake called Lake Lahontan near Lake Tahoe in Nevada and California, where deformation of the crust created fissures that could be filled up with liquid."

A creative application of a method previously used to analyze data at Mars also revealed that Ligeia Mare is about 560 feet (170 meters) deep. This is the first time scientists have been able to plumb the bottom of a lake or sea on Titan. This was possible partly because the liquid turned out to be very pure, allowing the radar signal to pass through it easily. The liquid surface may be as smooth as the paint on our cars, and it is very clear to radar eyes.

NASA / ESA Cassini spacecraft Titan fly-by. Image Credit: NASA/ESA

The new results indicate the liquid is mostly methane, somewhat similar to a liquid form of natural gas on Earth.

"Ligeia Mare turned out to be just the right depth for radar to detect a signal back from the sea floor, which is a signal we didn't think we'd be able to get," said Marco Mastrogiuseppe, a Cassini radar team associate at Sapienza University of Rome. "The measurement we made shows Ligeia to be deeper in at least one place than the average depth of Lake Michigan."

One implication is that Cassini scientists now can estimate the total volume of the liquids on Titan. Based on Mastrogiuseppe's work, calculations made by Alexander Hayes, of Cornell University in Ithaca, N.Y., show there are about 2,000 cubic miles (9,000 cubic kilometers) of liquid hydrocarbon, about 40 times more than in all the proven oil reservoirs on Earth.

As Cassini gets closer to northern summer in the Saturn system, mission scientists look forward to potentially the most exciting time for weather at Titan's northern hemisphere.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter. JPL and the Italian Space Agency, working with team members from the US and several European countries, built the radar instrument.

For more information about Cassini and its mission, visit:  http://www.nasa.gov/cassini  and http://saturn.jpl.nasa.gov and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Images (mentioned), Video, Text, Credits:  ESA / NASA / Dwayne Brown / JPL / Jia-Rui C. Cook.

Best regards, Orbiter.ch

Hubble Space Telescope Sees Evidence of Water Vapor Venting off Jupiter Moon














NASA - Hubble Space Telescope patch / ESA - Hubble Space Telescope patch.

Dec. 12, 2013

NASA’s / ESA's Hubble Space Telescope has observed water vapor above the frigid south polar region of Jupiter's moon Europa, providing the first strong evidence of water plumes erupting off the moon's surface.

Previous scientific findings from other sources already point to the existence of an ocean located under Europa's icy crust. Researchers are not yet fully certain whether the detected water vapor is generated by erupting water plumes on the surface, but they are confident this is the most likely explanation.

Should further observations support the finding, this would make Europa the second moon in the solar system known to have water vapor plumes. The findings are being published in the Dec. 12 online issue of Science Express, and reported at the meeting of the American Geophysical Union in San Francisco.

Artist's Concept of Europa Water Vapor Plume

Image above: This is an artist's concept of a plume of water vapor thought to be ejected off the frigid, icy surface of the Jovian moon Europa, located about 500 million miles (800 million kilometers) from the sun. Image Credit: NASA/ESA/K. Retherford/SWRI.

“By far the simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa,” said lead author Lorenz Roth of Southwest Research Institute in San Antonio. "If those plumes are connected with the subsurface water ocean we are confident exists under Europa's crust, then this means that future investigations can directly investigate the chemical makeup of Europa's potentially habitable environment without drilling through layers of ice. And that is tremendously exciting."

In 2005, NASA’s Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn’s moon Enceladus. Although ice and dust particles have subsequently been found in the Enceladus plumes, only water vapor gases have been measured at Europa so far.

Hubble spectroscopic observations provided the evidence for Europa plumes in December 2012. Time sampling of Europa's auroral emissions measured by Hubble's imaging spectrograph enabled the researchers to distinguish between features created by charged particles from Jupiter's magnetic bubble and plumes from Europa's surface, and also to rule out more exotic explanations such as serendipitously observing a rare meteorite impact.

Water Vapor Over Europa

Image above: This graphic shows the location of water vapor detected over Europa's south pole in observations taken by NASA's Hubble Space Telescope in December 2012. Image Credit: NASA/ESA/L. Roth/SWRI/University of Cologne.

The imaging spectrograph detected faint ultraviolet light from an aurora, powered by Jupiter’s intense magnetic field, near the moon’s south pole. Excited atomic oxygen and hydrogen produce a variable auroral glow and leave a telltale sign that are the products of water molecules being broken apart by electrons along magnetic field lines.

“We pushed Hubble to its limits to see this very faint emission. These could be stealth plumes, because they might be tenuous and difficult to observe in the visible light,” said Joachim Saur of the University of Cologne, Germany. Saur, who is principal investigator of the Hubble observation campaign, co-wrote the paper with Roth.

Roth suggested that long cracks on Europa’s surface, known as lineae, might be venting water vapor into space. Cassini has seen similar fissures that host the Enceladus jets.

Also the Hubble team found that the intensity of the Europa plumes, like those at Enceladus, varies with Europa’s orbital position. Active jets have only been seen when the moon is farthest from Jupiter. The researchers could not detect any sign of venting when Europa is closer to Jupiter.


Image above: NASA/ESA Hubble Space Telescope has discovered water vapour erupting from the frigid surface of Jupiter’s moon Europa. Image Credit: NASA/ESA

One explanation for the variability is that these lineae experience more stress as gravitational tidal forces push and pull on the moon and open vents at larger distances from Jupiter.  The vents are narrowed or closed when the moon is closest to the gas-giant planet.

"The apparent plume variability supports a key prediction that Europa should tidally flex by a significant amount if it has a subsurface ocean," said Kurt Retherford, also of Southwest Research Institute.

The Europa and Enceladus plumes have remarkably similar abundances of water vapor. Because Europa has a roughly 12 times stronger gravitational pull than Enceladus, the minus-40-degree-Fahrenheit (minus-40-degree-Celsius) vapor for the most part doesn’t escape into space as it does at Enceladus, but rather falls back onto the surface after reaching an altitude of 125 miles (201 kilometers), according to the Hubble measurements. This could leave bright surface features near the moon’s south polar region, the researchers hypothesize.

video
Flying Past Europa's Water Plumes

“If confirmed, this new observation once again shows the power of the Hubble Space Telescope to explore and opens a new chapter in our search for potentially habitable environments in our solar system,” said John Grunsfeld, an astronaut who participated Hubble servicing missions and now serves as NASA's associate administrator for science in Washington. “The effort and risk we took to upgrade and repair Hubble becomes all the more worthwhile when we learn about exciting discoveries like this one from Europa.”

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

To view the images of the evidence for plumes visit: http://www.nasa.gov/content/goddard/hubble-europa-water-vapor .

For more information about the Hubble Space Telescope, visit: http://www.nasa.gov/hubble  and http://www.spacetelescope.org/

Images (mentioned), Video, Text, Credits: ESA / NASA / Dwayne Brown / J.D. Harrington / Goddard Space Flight Center / Rob Gutro / JPL / Jia-Rui C. Cook / Southwest Research Institute / Joe Fohn.

Greetings, Orbiter.ch

Mystery mounds on Mars












ESA - Mars Express Mission patch.

Dec. 12, 2013

 Juventae Chasma

Intriguing mounds of light-toned layered deposits sit inside Juventae Chasma, surrounded by a bed of soft sand and dust.

The origin of the chasma is linked to faulting associated with volcanic activity more than 3 billion years ago, causing the chasma walls to collapse and slump inwards, as seen in the blocky terrain in the right-hand side of this image.

At the same time, fracturing and faulting allowed subsurface water to spill out and pool in the newly formed chasm. Observations by ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter show that the large mounds inside the chasma consist of sulphate-rich materials, an indication that the rocks were indeed altered by water.

The mounds contain numerous layers that were most likely built up as lake-deposits during the Chasma’s wet epoch. But ice-laden dust raining out from the atmosphere – a phenomenon observed at the poles of Mars – may also have contributed to the formation of the layers.

While the water has long gone, wind erosion prevails, etching grooves into the exposed surfaces of the mounds and whipping up the surrounding dust into ripples.

The image was taken by the high-resolution stereo camera on ESA’s Mars Express on 4 November 2013 (orbit 12 508), with a ground resolution of 16 m per pixel. The image centre is at about 4°S / 298°E.

Juventae Chasma context

Juventae Chasma was imaged by the high-resolution stereo camera on ESA’s Mars Express on 4 November 2013 during orbit 12 508. The area presented in the related images is outlined by the smaller rectangle.

Juventae Chasma is located north of the vast Valles Marineris canyon and extends some 150 km in the east–west direction and 250 km north–south.

Juventae Chasma topography

Colour-coded topography map of Juventae Chasma. White and red show the highest terrains, while blue and purple show the deepest.

The floor of Juventae Chasma sits some 5.8 km below the surrounding plateau. It is filled with sand in the southern part (left), which takes on a smooth appearance, in contrast to the northern (right) part of this image where many blocky rock fragments have slumped down from the chasma walls. Two large mounds of layered material sit inside Juventae Chasma and comprise minerals altered by water.

This region was imaged by the high-resolution stereo camera on ESA’s Mars Express on 4 November 2013 (orbit 12 508), with a ground resolution of 16 ms per pixel. The image centre is at about 4°S / 298°E.

Juventae Chasma perspective

The largest layered mound in Juventae Chasma is seen here in close-up perspective view. It is about 53 km long, up to 20 km wide and rises some 3.3 km above the surrounding area, comparable to a small mountain range on Earth.

Its surface is etched with grooves carved by strong prevailing winds blowing through the chasma. Layers in the mound consist of sulphate-rich materials, an indication that the rocks have been altered by water.

The mound is a relic of at least 3 billion years of martian history and its layers were most likely built up as lake deposits over time. But ice-laden dust raining out from the atmosphere – a phenomenon observed at the poles of Mars – may also have contributed to the formation of the layers.

This region was imaged by the high-resolution stereo camera on ESA’s Mars Express on 4 November 2013 (orbit 12,508), with a ground resolution of 16 m per pixel. The image centre is at about 4°S / 298°E.

Juventae Chasma 3D

Data from the nadir channel and one stereo channel of the high-resolution stereo camera on ESA’s Mars Express have been combined to produce this anaglyph 3D image of Juventae Chasma, which can be viewed using stereoscopic glasses with red–green or red–blue filters.

This region was imaged on 4 November 2013 (orbit 12 508), with a ground resolution of 16 ms per pixel. The image centre is at about 4°S / 298°E.

For more information about Mars Express Mission, visit: http://www.esa.int/Our_Activities/Space_Science/Mars_Express and http://sci.esa.int/mars-express/

Images, Text, Credits: ESA/DLR/FU Berlin (G. Neukum).

Cheers, Orbiter.ch

mercredi 11 décembre 2013

Clay-Like Minerals Found on Icy Crust of Europa












NASA - Galileo Mission patch.

December 11, 2013

A new analysis of data from NASA's Galileo mission has revealed clay-type minerals at the surface of Jupiter's icy moon Europa that appear to have been delivered by a spectacular collision with an asteroid or comet. This is the first time such minerals have been detected on Europa's surface. The types of space rocks that deliver such minerals typically also often carry organic materials.


This image, using data from NASA's Galileo mission, shows the first detection of clay-like minerals on the surface of Jupiter's moon Europa. Image credit: NASA/JPL-Caltech/SETI.

"Organic materials, which are important building blocks for life, are often found in comets and primitive asteroids," said Jim Shirley, a research scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Shirley is giving a talk on this topic at the American Geophysical Union meeting in San Francisco on Friday, Dec. 13. "Finding the rocky residues of this comet crash on Europa's surface may open up a new chapter in the story of the search for life on Europa," he said.

Many scientists believe Europa is the best location in our solar system to find existing life. It has a subsurface ocean in contact with rock, an icy surface that mixes with the ocean below, salts on the surface that create an energy gradient, and a source of heat (the flexing that occurs as it gets stretched and squeezed by Jupiter's gravity). Those conditions were likely in place shortly after Europa first coalesced in our solar system.

Scientists have also long thought there must be organic materials at Europa, too, though they have yet to detect them directly. One theory is that organic material could have arrived by comet or asteroid impacts, and this new finding supports that idea.

Shirley and colleagues, funded by a NASA Outer Planets Research grant, were able to see the clay-type minerals called phyllosilicates in near-infrared images from Galileo taken in 1998. Those images are low resolution by today's standards, and Shirley's group is applying a new technique for pulling a stronger signal for these materials out of the noisy picture. The phyllosilicates appear in a broken ring about 25 miles (40 kilometers) wide, which is about 75 miles (120 kilometers) away from the center of a 20-mile-diameter (30 kilometers) central crater site.


This artist's concept shows a possible explosion resulting from a high-speed collision between a space rock and Jupiter's moon Europa. Image credit: NASA/JPL-Caltech.

The leading explanation for this pattern is the splash back of material ejected when a comet or asteroid hits the surface at an angle of 45 degrees or more from the vertical direction. A shallow angle would allow some of the space rock's original material to fall back to the surface. A more head-on collision would likely have vaporized it or driven that space rock's materials below the surface. It is hard to see how phyllosilicates from Europa's interior could make it to the surface, due to Europa's icy crust, which scientists think may be up to 60 miles (100 kilometers) thick in some areas.

Therefore, the best explanation is that the materials came from an asteroid or comet. If the body was an asteroid, it was likely about 3,600 feet (1,100 meters) in diameter. If the body was a comet, it was likely about 5,600 feet (1,700 meters) in diameter. It would have been nearly the same size as the comet ISON before it passed around the sun a few weeks ago.

"Understanding Europa's composition is key to deciphering its history and its potential habitability," said Bob Pappalardo of JPL, the pre-project scientist for a proposed mission to Europa. "It will take a future spacecraft mission to Europa to pin down the specifics of its chemistry and the implications for this moon hosting life."

For more information about Europa, visit: http://solarsystem.nasa.gov/europa/home.cfm .

JPL is a division of the California Institute of Technology in Pasadena.

Images (mentioned), Text, Credits: NASA / JPL / Jia-Rui C. Cook.

Best regards, Orbiter.ch

Antarctica's Ice Loss on the Rise







ESA - CRYOSAT Mission logo.

11 December 2013

Three years of observations by ESA’s CryoSat satellite show that the West Antarctic Ice Sheet is losing over 150 cubic kilometres of ice each year – considerably more than when last surveyed.

The imbalance in West Antarctica continues to be dominated by ice losses from glaciers flowing into the Amundsen Sea.

“We find that ice thinning continues to be most pronounced along fast-flowing ice streams of this sector and their tributaries, with thinning rates of between 4–8 m per year near to the grounding lines – where the ice streams lift up off the land and begin to float out over the ocean – of the Pine Island, Thwaites and Smith Glaciers,” said Dr Malcolm McMillan from the University of Leeds, UK.

Thinning ice

Melting of ice sheets that blanket Antarctica and Greenland is a major contributor to global sea-level rise.

An international team of polar scientists had recently concluded that West Antarctica caused global sea levels to rise by 0.28 mm each year between 2005 and 2010, based on observations from 10 different satellite missions. But the latest research from CryoSat suggests that the sea level contribution from this area is now 15% higher.

Launched in 2010, CryoSat carries a radar altimeter that can ‘see’ through clouds and in the dark, providing continuous measurements over areas like Antarctica that are prone to bad weather and long periods of darkness.

The radar can measure the surface height variation of ice in high resolution, allowing scientists to calculate its volume accurately.

Professor Andrew Shepherd from the University of Leeds, who led the West Antarctica study, said that part of the increase of ice loss could be due to faster thinning, but that part of it may also be down to CryoSat’s capacity to observe previously unseen terrain.

CryoSat

“Thanks to its novel instrument design and to its near-polar orbit, CryoSat allows us to survey coastal and high-latitude regions of Antarctica that were beyond the capability of previous altimeter missions, and it seems that these regions are crucial for determining the overall imbalance,” he said.

The findings from a team of UK researchers at the Natural Environment Research Council’s Centre for Polar Observation and Modelling were presented this week at the American Geophysical Union’s autumn meeting in San Francisco, California.

The meeting brings together more than 20 000 Earth and space scientists, educators and students to showcase their research. ESA is also presenting the latest scientific results from its Earth observation missions.

Pine Island Glacier

CryoSat has been providing a unique capacity to extend the record of Antarctic altimeter observations, following on from the 20-year record acquired by altimeters on the ERS-1, ERS-2 and Envisat satellites.

Satellites being developed for Europe’s Copernicus programme will continue to monitor changes in the polar ice sheets during the coming decades with radar sensors on the Sentinel-1 and Sentinel-3 satellite series, scheduled to be launched from 2014 onwards.

Related links:

NERC Centre for Polar Observation and Modelling: http://www.cpom.org/

University of Leeds: http://www.leeds.ac.uk/

AGU Fall Meeting 2013: http://fallmeeting.agu.org/2013/

CryoSat: an icy mission: http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat/CryoSat_an_icy_mission

Images, Text, Credits: ESA / P. Carril / CPOM / Tom Kellogg.

Greetings, Orbiter.ch

mardi 10 décembre 2013

Fire vs. Ice: The Science of ISON at Perihelion














NASA / ESA - SOHO Mission patch / NASA - Solar Dynamics Observatory (SDO) patch.

Dec. 10, 2013

video
 Comet ISON's Full Perihelion Pass

Video above: After several days of continued observations, scientists continue to work to determine and understand the fate of Comet ISON: There's no doubt that the comet shrank in size considerably as it rounded the sun and there's no doubt that something made it out on the other side to shoot back into space.Image Credit: ESA/NASA/SOHO.

After a year of observations, scientists waited with bated breath on Nov. 28, 2013, as Comet ISON made its closest approach to the sun, known as perihelion. Would the comet disintegrate in the fierce heat and gravity of the sun? Or survive intact to appear as a bright comet in the pre-dawn sky?

Some remnant of ISON did indeed make it around the sun, but it quickly dimmed and fizzled as seen with NASA's solar observatories. This does not mean scientists were disappointed, however. A worldwide collaboration ensured that observatories around the globe and in space, as well as keen amateur astronomers, gathered one of the largest sets of comet observations of all time, which will provide fodder for study for years to come.

NASA / ESA SOHO spacecraft. Image Credit: ESA/NASA

On Dec. 10, 2013, researchers presented science results from the comet's last days at the 2013 Fall American Geophysical Union meeting in San Francisco, Calif. They described how this unique comet lost mass in advance of reaching perihelion and most likely broke up during its closest approach, as well, as summarized what this means for determining what the comet was made of.

"The comet's story begins with the very formation of the solar system," said Karl Battams, an astrophysicist at the Naval Research Lab in Washington, D.C. "The dirty snowball that we came to call Comet ISON was created at the same time as the planets."

ISON circled the solar system in the Oort cloud, more than 4.5 trillion miles away from the sun. At some point a few million years ago, something occurred – perhaps the passage of a nearby star – to knock ISON out of its orbit and send it hurtling along a path for its first trip into the inner solar system.

The comet was first spotted 585 million miles away in September 2012 by two Russian astronomers: Vitali Nevski and Artyom Novichonok. The comet was named after the project that discovered it, the International Scientific Optical Network, or ISON, and given an official designation of C/2012 S1 (ISON). When comet scientists mapped out Comet ISON's orbit they learned that the comet would swing within 1.1 million miles of the sun's surface, making it what's known as a sungrazing comet, providing opportunities to study this pristine bit of the early solar system as it lost material while approaching the higher temperatures of the sun. With this knowledge, an international campaign to observe the comet was born. The number of space-based, ground-based, and amateur observations was unprecedented, including 12 NASA space-based assets observing Comet ISON over the past year.

Near the beginning of October, 2013, two months before perihelion, NASA's Mars Reconnaissance Orbiter, or MRO, turned its HiRISE instrument to view the comet during its closest approach to Mars in October 2013.

Mars Reconnaissance Orbiter. Image Credit: NASA/JPL-Caltech

"The size of ISON's nucleus could be a little over half a mile across --- at the most.  Very likely it could have been as small as several hundred yards," said Alfred McEwen, the principal investigator for the HiRISE instrument at Arizona State University, in Tucson.

In other words, Comet ISON might have been the length of five or six football fields. This small size was near the borderline of how big ISON needed to be to survive its trip around the sun.

During that trip around the sun, Geraint Jones, a comet scientist at University College London's Mullard Space Science Laboratory in the UK studied the comet's dust tails to better understand what happened as it rounded the sun. By fitting models of the dust tail to the actual observations from NASA's Solar Terrestrial Observatory, or STEREO, and the joint European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, Jones showed that very little dust was produced after perihelion, which may suggest that the comet's nucleus had already broken up by that time.


Image above: This image from NASA's Solar Dynamics Observatory shows the sun, but no Comet ISON was seen. A white plus sign shows where the Comet should have appeared. Image Credit: NASA/SDO.

While the comet was visible in STEREO and SOHO images going into perihelion, it was not visible in the data from NASA's Solar Dynamics Observatory, or SDO, or from ground based solar observatories during its closest approach to the sun. Dean Pesnell, project scientist for SDO at NASA's Goddard Space Flight Center in Greenbelt, Md., explained why Comet ISON wasn't visible in SDO and what could be learned from that: SDO is tuned to see wavelengths of light that would indicate the presence of oxygen, which is very common in comets.

Solar Dynamics Observatory (SDO) spacecraft. Image Credit: NASA

"The fact that ISON did not show oxygen despite how close it came to the sun provides information about how high was the evaporation temperature of ISON's material," said Pesnell. "This limits what it could have been made of."

When Comet ISON was first spotted in September 2012, it was relatively bright for a comet at such a great distance from the sun. Consequently, many people had high hopes it would provide a beautiful light show visible in the night sky throughout December 2013. That potential ended when Comet ISON disrupted during perihelion. However, the legacy of the comet will go on for years as scientists analyze the tremendous data set collected during ISON's journey.

Related Links:

International Scientific Optical Network, or ISON: http://en.wikipedia.org/wiki/International_Scientific_Optical_Network

NASA's Comet ISON website: http://www.nasa.gov/cometison

Download high resolution media: http://svs.gsfc.nasa.gov/goto?11434

Briefing Presentation: http://www.nasa.gov/sites/default/files/files/AGU2013-CometISON-pressconference.pdf

Images (mentioned), Video (mentioned), Text, Credits: NASA's Goddard Space Flight Center / Karen C. Fox.

Greetings, Orbiter.ch

Mars Spacecraft Reveals a More Dynamic Red Planet














NASA - Mars ODYSSEY Mission patch / NASA - Mars Reconnaissance Orbiter (MRO) patch.

Dec. 10, 2013

 Seasonal Changes in Dark Marks on an Equatorial Martian Slope

Image above: These images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter show how the appearance of dark markings on Martian slope changes with the seasons. Image Credit: NASA/JPL-Caltech/Univ. of Arizona.

NASA's Mars Reconnaissance Orbiter has revealed to scientists slender dark markings -- possibly due to salty water – that advance seasonally down slopes surprisingly close to the Martian equator.

"The equatorial surface region of Mars has been regarded as dry, free of liquid or frozen water, but we may need to rethink that," said Alfred McEwen of the University of Arizona in Tucson, principal investigator for the Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) camera.

Tracking how these features recur each year is one example of how the longevity of NASA orbiters observing Mars is providing insight about changes on many time scales. Researchers at the American Geophysical Union meeting Tuesday in San Francisco discussed a range of current Martian activity, from fresh craters offering glimpses of subsurface ice to multi-year patterns in the occurrence of large, regional dust storms.

The seasonally changing surface flows were first reported two years ago on mid-latitude southern slopes. They are finger-like features typically less than 16 feet (5 meters) wide that appear and extend down steep, rocky slopes during spring through summer, then fade in winter and return the next spring. Recently observed slopes stretch as long as 4,000 feet (1,200 meters).

Long, Recurring Linear Marking on Martian Slope

Image above: These images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter show how the appearance of dark markings on Martian slope changes with the seasons. Image Credit: NASA/JPL-Caltech/Univ. of Arizona.

McEwen and co-authors reported the equatorial flows at the conference and in a paper published online Tuesday by Nature Geoscience. Five well-monitored sites with these markings are in Valles Marineris, the largest canyon system in the solar system. At each of these sites, the features appear on both north- and south-facing walls. On the north-facing slopes, they are active during the part of the year when those slopes get the most sunshine. The counterparts on south-facing slopes start flowing when the season shifts and more sunshine hits their side.

"The explanation that fits best is salty water is flowing down the slopes when the temperature rises," McEwen said. "We still don't have any definite identification of water at these sites, but there's nothing that rules it out, either."

Dissolved salts can keep water melted at temperatures when purer water freezes, and they can slow the evaporation rate so brine can flow farther. This analysis used data from the Compact Reconnaissance Imaging Spectrometer for Mars and the Context Camera on the MRO as well as the Thermal Emission Imaging System experiment on NASA's Mars Odyssey orbiter.

Water ice has been identified in another dynamic process researchers are monitoring with MRO. Impacts of small asteroids or bits of comets dig many fresh craters on Mars every year. Twenty fresh craters have exposed bright ice previously hidden beneath the surface. Five were reported in 2009. The 15 newly reported ones are distributed over a wider range of latitudes and longitudes.

Icy Material Thrown from Cratering Impact on Mars

Image above: This image taken on May 19, 2010, shows an impact crater that had not existed when the same location on Mars was previously observed in March 2008. Image Credit: NASA/JPL-Caltech/Univ. of Arizona.

"The more we find, the more we can fill in a global map of where ice is buried," said Colin Dundas of the U.S. Geological Survey in Flagstaff, Ariz. "We've now seen icy craters down to 39 degrees north, more than halfway from the pole to the equator. They tell us that either the average climate over several thousand years is wetter than present or that water vapor in the current atmosphere is concentrated near the surface. Ice could have formed under wetter conditions, with remnants from that time persisting today, but slowly disappearing."

Mars' modern climate becomes better known each year because of a growing set of data from a series of orbiters that have been studying Mars continually since 1997. That has been almost nine Martian years because a year on Mars is almost two years long on Earth. Earlier missions and surface landers have added insight about the dynamics of Mars' atmosphere and its interaction with the ground.

Mars Odyssey spacecraft. Image Credit: NASA/JPL-Caltech

"The dust cycle is the main driver of the climate system," said Robert Haberle of NASA's Ames Research Center in Moffett Field, Calif.

One key question researchers want to answer is why dust storms encircle Mars in some years and not in others. These storms affect annual patterns of water vapor and carbon dioxide in the atmosphere, freezing into polar ice caps in winter and replenishing the atmosphere in spring. Identifying significant variations in annual patterns requires many Martian years of observations.

The data emerging from long-term studies will help future human explorers of Mars know where to find resources such as water, how to prepare for hazards such as dust storms, and where to be extra careful about contamination with Earth microbes.

Mars Reconnaissance Orbiter spacecraft. Image Credit: NASA/JPL-Caltech

Launched in 2005, Mars Reconnaissance Orbiter and its six instruments have provided more high-resolution data about the Red Planet than all other Mars orbiters combined. Data are made available for scientists worldwide to research, analyze and report their findings.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the MRO and Mars Odyssey missions for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built both orbiters. The University of Arizona Lunar and Planetary Laboratory operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp. of Boulder, Colo.

For more information about NASA Mars exploration missions, visit: http://www.nasa.gov/mars

For more about HiRISE, visit: http://hirise.lpl.arizona.edu

NASA / Dwayne Brown / JPL / Guy Webster.