Category: Mars

Image credit: NASA/JPL

NASA’s twin rovers, Spirit and Opportunity, are still on track to reach the Red Planet in early January. Spirit, which launched first, is scheduled to arrive on the evening of January 3, 2004 near the centre of Gusev Crater, which might have held a lake in the past. The spacecraft will jettison its cruise stage 15 minutes before hitting the top of the Martian atmosphere, and then will slow down to only 1,500 kph before deploying its parachute. 20 seconds later its retrorockets will fire and the spacecraft will cushion its final few metres with an airbag. The rover will then spend three months exploring the Martian surface.

NASA’S robotic Mars geologist, Spirit, embodying America’s enthusiasm for exploration, must run a grueling gantlet of challenges before it can start examining the red planet. Spirit’s twin Mars Exploration Rover, Opportunity, also faces tough Martian challenges.

“The risk is real, but so is the potential reward of using these advanced rovers to improve our understanding of how planets work,” said Dr. Ed Weiler, associate administrator for space science at NASA Headquarters, Washington.

Spirit is the first of two golf-cart-sized rovers headed for Mars landings in January. The rovers will seek evidence about whether the environment in two regions might once have been capable of supporting life. Engineers at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif., have navigated Spirit to arrive during the evening of Jan. 3, 2004, in the Eastern time zone.

Spirit will land near the center of Gusev Crater, which may have once held a lake. Three weeks later, Opportunity will reach the Meridiani Planum, a region containing exposed deposits of a mineral that usually forms under watery conditions.

“We’ve cleared two of the big hurdles, building both spacecraft and launching them,” said JPL’s Peter Theisinger, project manager for the Mars Exploration Rover Project. “Now we’re coming up on a third, getting them safely onto the ground,” he said.

Since their launches on June 10 and July 7 respectively, each rover has been flying tucked inside a folded-up lander. The lander is wrapped in deflated airbags, cocooned within a protective aeroshell and attached to a cruise stage that provides solar panels, antennas and steering for the approximately seven month journey.

Spirit will cast off its cruise stage 15 minutes before hitting the top of the Martian atmosphere at 5,400 meters per second (12,000 miles per hour). Atmospheric friction during the next four minutes will heat part of the aeroshell to about 1,400 C (2,600 F) and slow the descent to about 430 meters per second (960 mph). Less than two minutes before landing, the spacecraft will open its parachute.

Twenty seconds later, it will jettison the bottom half of its aeroshell, exposing the lander. The top half of the shell, still riding the parachute, will lower the lander on a tether. In the final six seconds, airbags will inflate, retro rockets on the upper shell will fire, and the tether will be cut about 15 meters (49 feet) above the ground.

Several bounces and rolls could take the airbag-cushioned lander about a kilometer (0.6 mile) from where it initially lands. If any of the initial few bounces hits a big rock that’s too sharp, or if the spacecraft doesn’t complete each task at just the right point during the descent, the mission could be over. More than half of all the missions launched to Mars have failed.

JPL Director Dr. Charles Elachi said, “We have done everything we know that could be humanly done to ensure success. We have conducted more testing and external reviews for the Mars Exploration Rovers than for any previous interplanetary mission.”

Landing safely is the first step for three months of Mars exploration by each rover. Before rolling off its lander, each rover will spend a week or more unfolding itself, rising to full height, and scanning surroundings. Spirit and Opportunity each weigh about 17 times as much as the Sojourner rover of the 1997 Mars Pathfinder mission. They are big enough to roll right over obstacles nearly as tall as Sojourner.

“Think of Spirit and Opportunity as robotic field geologists,” said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers’ identical sets of science instruments. “They look around with a stereo, color camera and with an infrared instrument that can classify rock types from a distance. They go to the rocks that seem most interesting. When they get to one, they reach out with a robotic arm that has a handful of tools, a microscope, two instruments for identifying what the rock is made of, and a grinder for getting to a fresh, unweathered surface inside the rock,” he said.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington. For information about the Mars Exploration Rover project on the Internet, visit:

http://space.mit.edu/HETE/

For Cornell University’s Web site about the science payload, visit:

http://athena.cornell.edu

Original Source: NASA/JPL News Release

Image credit: NASA/JPL

During a recent solar storm, an instrument on board NASA’s Mars Odyssey spacecraft failed, and so far, operators haven’t been able to get it working again. The Martian Radiation Environment (MARIE) was designed to measure the radiation in the Martian space environment, which will help mission planners understand what kinds of risks humans might face if they traveled to the Red Planet. Operators will continue their attempts to get the instrument working for a few weeks before writing it off.

The martian radiation environment experiment on NASA?s 2001 Mars Odyssey orbiter has collected data continuously from the start of the Odyssey mapping mission in March 2002 until late last month. The instrument has successfully monitored space radiation to evaluate the risks to future Mars-bound astronauts. Its measurements are the first of their kind to be obtained during an interplanetary cruise and in orbit around another planet.

On Oct. 28, 2003, during a period of intense solar activity, the instrument stopped working properly. Controllers? efforts to restore the instrument to normal operations have not been successful. These efforts will continue for the next several weeks or months.

The martian radiation environment experiment detects energetic charged particles, including galactic cosmic rays and particles emitted by the Sun in coronal mass ejections. The dose equivalent from galactic cosmic rays as measured by the instrument agrees well with predictions based on modeling. Validation of radiation models is a crucial step in predicting radiation-related health risks for crews of future missions.

“Even if the instrument provides no additional data in the future, it has been a great success at characterizing the radiation environment that a crewed mission to Mars would need to anticipate,” said Dr. Jeffrey Plaut, project scientist for Mars Odyssey at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

JPL manages the Mars Odyssey and Global Surveyor missions for NASA’s Office of Space Science, Washington, D.C. Investigators at Arizona State University, Tempe; University of Arizona, Tucson; NASA’s Johnson Space Center, Houston; the Russian Aviation and Space Agency, Moscow; and Los Alamos National Laboratory, Los Alamos, N.M., built and operate Odyssey science instruments. Information about NASA’s Mars exploration program is available on the Internet at: http://mars.jpl.nasa.gov.

Original Source: NASA/JPL News Release

Image credit: NASA/JPL

In case you’d forgotten about them, NASA’s twin Mars Exploration spacecraft, Spirit and Opportunity, are still on their way to the Red Planet. Spirit made its third trajectory correction last week to fine-tune its flight path as it gets closer. Both rovers have rebooted their computers in the past two weeks to remove any data errors that could have caused by the recent powerful solar storms. Spirit should arrive at the Gusev Crater on January 4, 2004, while Opportunity will land Meridiani Planum on January 25.

NASA’s Spirit spacecraft made its third trajectory correction maneuver on Friday, Nov. 14, fine tuning its flight path toward Mars with an engine-firing operation planned into the seven-month trip.

The trajectory adjustment was designed to alter Spirit’s velocity by 0.6 meters per second (1.3 miles per hour), moving the arrival point by 770 kilometers (478 miles) and arrival time by 16.5 minutes closer to the planned target location and time, said Louis D’Amario, the project’s navigation team chief. To accomplish that adjustment, the flight team commanded Spirit to fire its engines for 132 seconds in the direction of the spacecraft’s rotation axis and for short pulses totaling 27 seconds in a direction roughly perpendicular to the rotation axis.

Spirit has three more scheduled dates for additional trajectory corrections before reaching Mars less than seven weeks from now. The spacecraft is carrying the first of two Mars Exploration Rovers equipped to examine the geology around their landing sites for evidence about past environmental conditions.

Both Spirit and its twin, Opportunity, have rebooted their computers in the past two weeks. Mission controllers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., sent commands for that procedure on each spacecraft to correct possible corruption of computer memory registers by radiation from powerful solar flares in late October and early November. The flares were among the most intense ever recorded.

“We had no evidence of memory problems, but we considered it prudent to reboot both spacecraft to assure memory integrity, using the sleep-wake cycle that we plan to do each night after the rovers are on the surface of Mars,” said JPL’s Peter Theisinger, project manager for the Mars Exploration Rover Project.

High-energy protons ejected by the stormy Sun appeared on Oct. 28 as bursts of bright spots in star-tracking instruments used by both Spirit and Opportunity to sense the spacecrafts’ orientation. The instruments interpreted the proton hits as stars, so the bursts overwhelmed their ability to recognize star patterns and determine spacecraft attitude. Both spacecraft temporarily switched to a backup method of attitude sensing, using the Sun. They resumed use of the star trackers last week.

Spirit’s target is arrival at Mars’ Gusev Crater at 04:35 Jan. 4, 2004, Universal Time (8:35 p.m. Jan. 3, Pacific Standard Time and 11:35 p.m. Jan. 3, Eastern Standard Time). These are “Earth received times,” meaning they reflect the delay necessary for a speed-of-light signal from Mars to reach Earth; on Mars, the landing will have happened nearly 10 minutes earlier. Three weeks later, at 05:05 Jan. 25, Universal Time, Opportunity will arrive at a level plain called Meridiani Planum on the opposite side of Mars from Gusev. Each rover will examine its landing area for geological evidence about the history of water there, key information for assessing whether the site ever could have been hospitable to life.

As of 6 a.m. PST on Nov. 19, Spirit had traveled 396.5 million kilometers (246.4 million miles) since its June 10 launch, with 91.5 million kilometers (56.2 million miles) to go before reaching Mars. Opportunity, launched on July 7, had traveled 326 million kilometers (202 million miles) and has 130 million kilometers (81 million miles) yet to go.

JPL, a division of the California Institute of Technology, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Additional information about the project is available from JPL at http://mars.jpl.nasa.gov/mer and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.

Original Source: NASA/JPL News Release

Image credit: ESA

The European Space Agency is planning a mission to study the surface of Mars by picking up material from the surface and returning it to the Earth. The Mars Sample Return mission will consist of two parts: the return capsule will launch in 2011 and go into orbit around Mars; the lander and ascent module will launch two years later and land on the planet to collect a sample from a depth of 2 metres. It will then launch into Mars’ orbit, link up with the return capsule, and bring the sample back to the Earth.

What is the next best thing to humans landing on Mars and exploring the wonders of the Red Planet? The answer: touching, imaging and analysing carefully preserved samples of Martian rock in a state-of-the-art laboratory on Earth.

If all goes according to plan, this is exactly what ESA?s long-term Aurora Programme of solar system exploration will achieve a decade from now, when the first samples of Mars material will be sealed in a special capsule and returned to Earth for analysis.

The first step towards making this great leap in human knowledge a reality was taken at the end of October with the announcement of the winners of competitive contracts for the Mars Sample Return (MSR) mission, the second Flagship robotic mission to be proposed as part of Aurora.

The parallel contracts for the Phase A studies that will carry out a full mission design iteration for the MSR have been placed with two industrial teams.

One team, headed by Alenia Spazio (Italy), includes Alcatel (France), Dutch Space (Netherlands), ELV (Italy) and MDR (Canada). The other team, headed by EADS Astrium (UK), also includes Astrium SAS (France), EADS ST (France), Galileo Avionica (Italy), RAL (UK), SAS (Belgium), SENER (Spain) and Utopia Consultancies (Germany).

?The industrial proposals received were of outstanding quality, reflecting the enthusiasm and the commitment of the industrial teams who prepared them,? said Bruno Gardini, Aurora Project Manager.

Bringing Mars back to Earth
As currently envisaged, the MSR will be a two-stage endeavour. First, a spacecraft that includes a return capsule will be launched in 2011 and inserted into orbit around Mars. Then, two years later, a second spacecraft carrying a descent module and a Mars ascent vehicle (MAV) will be launched on a similar trajectory.

During its final approach to Mars, the descent module/MAV will be released and make a controlled landing on the planet. A robotic drill will then collect a soil sample from a depth of 1? to 2 metres and seal it inside a small canister on the ascent vehicle. Other samples of Martian soil and air may also be gathered and stored inside the canister.

Carrying its precious samples, the MAV will lift off from the surface, then rendezvous and dock with the spacecraft in Martian orbit. After receiving the canister loaded with Martian rocks, the spacecraft will return to Earth with the re-entry capsule containing the samples and send it plummeting into the atmosphere.

Slowed by a parachute or inflatable device, the capsule will make a fairly gentle touchdown before recovery teams retrieve the container from the landing site and deliver it to a planetary protection facility where the samples will be removed to await analysis by eager scientists. The design of the capsule will ensure that the structural integrity of the sample container remains intact, even if the parachute fails to open and a crash landing occurs.

?The Mars Sample Return mission is one of the most challenging missions ever considered by ESA,? said Gardini. ?Not only does it include many new technologies and four or five different spacecraft, but it is also a mission of tremendous scientific importance and the first robotic mission with a similar profile to a possible human expedition to Mars.?

A number of the critical technologies required for the success of this ambitious endeavour have yet to be developed in Europe, e.g. re-entry of spacecraft arriving from deep space at a high velocity. As a preliminary stage in developing a vehicle capable of bringing back samples from Mars, it was considered necessary to develop this re-entry capability and to demonstrate its maturity as part of the Aurora Programme. Feasibility studies for a dedicated Arrow mission, known as the Earth re-entry Vehicle Demonstrator (EVD), were recently announced.

In the same way, testing of the complex rendezvous and docking techniques will be carried out as an experiment on the ExoMars mission, the first Flagship mission of the Aurora Programme. The Phase A industrial study contracts for the ExoMars mission began in September.

Original Source: ESA News Release

Image credit: NASA/JPL

The NASA/ASU THEMIS imaging team has released a photo of Mars which has been corrected as close as possible to realistic colour. This image of cliffs and basalt sand dunes in the southern Melas Chasma region of Mars was taken by NASA’s Mars Odyssey spacecraft. Astronomer and space artist Don Davis used photographs from the Hubble Space Telescope and his own experience to modify the colours in the picture until they looked natural.

This spectacular view of the sunlit cliffs and basaltic sand dunes in southern Melas Chasma shows Mars in a way rarely seen: in full, realistic color. The colorization is the result of a collaboration between THEMIS team members at Cornell University and space artist Don Davis, who is an expert on true-color renderings of planetary and astronomical objects. Davis began with calibrated and co-registered THEMIS VIS multi-band radiance files produced by the Cornell group. Using as a guide true-color imaging from the Hubble Space Telescope and his own personal experience at Mt. Wilson and other observatories, he performed a manual color balance to match more closely the colors of previous visual Mars observations. He also did some manual smoothing and other image processing to mimimize the effects of residual scattered light in the images. The result is a view of Mars that invites comparisons to Earth; a scene that one might observe out the window on a flight over the southwest United States, but not quite. The basaltic dunes are commonplace on Mars but a rare feature on Earth. The rounded knobs and elongated mesas on the canyon floor show an erosional style as exotic as Utah’s Bryce Canyon but wholly familiar on Mars. Although the inhospitable Martian atmosphere cannot be seen, the magnificent Martian landscape on display in this image beckons space-suited human explorers and the sightseers who will follow.

Initial image processing and calibration by THEMIS team members J. Bell, T. McConnochie, and D. Savransky at Cornell University; additional processing and final color balance by space artist Don Davis.

Original Source: NASA/ASU News Release

The Mars-bound Japanese spacecraft Nozomi, which has been plagued with problems since its launch in 1998, could be on a collision course with the Red Planet, and might crash into it if engineers can’t change its trajectory. Officials from the Japanese space agency will attempt to fire the spacecraft’s engines on December 8 to kick it into a safer orbit. But before that, they need to fix the spacecraft’s malfunctioning electrical. One worry is that Nozomi was never intended to enter Mars’ atmosphere, so it wasn’t carefully decontaminated – it could deliver Earth-based microbes to the Martian surface.

Image credit: NASA/JPL

NASA’s Mars Global Surveyor spacecraft has revealed new features on Mars that look like ancient river deltas. This discovery might help answer the mystery of how long water flowed on the surface of the Red Planet. The shape of this formation suggests that a river flowed into a body of water for quite a while, changing its course and building up layers of sediment over time. The area is about 13 km long and 11 km wide, and located in a crater in the southern hemisphere.

Newly seen details in a fan-shaped apron of debris on Mars may help settle a decades-long debate about whether the planet had long-lasting rivers instead of just brief, intense floods.

Pictures from NASA’s Mars Global Surveyor orbiter show eroded ancient deposits of transported sediment long since hardened into interweaving, curved ridges of layered rock. Scientists interpret some of the curves as traces of ancient meanders made in a sedimentary fan as flowing water changed its course over time.

“Meanders are key, unequivocal evidence that some valleys on early Mars held persistent flows of water over considerable periods of time,” said Dr. Michael Malin of Malin Space Science Systems, San Diego, which supplied and operates the spacecraft’s Mars Orbiter Camera.

“The shape of the fan and the pattern of inverted channels in it suggest it may have been a real delta, a deposit made where a river enters a body of water,” he said. “If so, it would be the strongest indicator yet Mars once had lakes.”

Malin and Dr. Ken Edgett, also of Malin Space Science Systems, have published pictures and analysis of the landform in today’s online edition of Science Express. The images with captions are available online from the Mars Orbiter Camera team, at http://www.msss.com/mars_images/moc/2003/11/13/ and from NASA’s Jet Propulsion Laboratory, Pasadena, Calif., at http://photojournal.jpl.nasa.gov/catalog/PIA04869.

The fan covers an area about 13 kilometers (8 miles) long and 11 kilometers (7 miles) wide in an unnamed southern hemisphere crater downslope from a large network of channels that apparently drained into it billions of years ago.

“This latest discovery by the intrepid Mars Global Surveyor is our first definitive evidence of persistent surface water,” commented Dr. Jim Garvin, NASA’s Lead Scientist for Mars Exploration, NASA Headquarters, Washington, D.C. “It reaffirms we are on the right pathway for searching the record of martian landscapes and eventually rocks for the record of habitats. Such localities may serve as key landing sites for future missions, such as the Mars Science Laboratory in 2009,” continued Garvin. “These astounding findings suggest that “following the water” with Mars Global Surveyor, Mars Odyssey, and soon with the Mars Exploration Rovers, is a powerful approach that will ultimately allow us to understand the history of habitats on the red planet.”

No liquid water has been detected on Mars, although one of the previous major discoveries from Mars Global Surveyor pictures suggests that some gullies have been cut in geologically recent times by the flow of ephemeral liquid water. Another NASA orbiter, Mars Odyssey, has discovered extensive deposits of near-surface ice at high latitudes. Mars’ atmosphere is now so thin that, over most of the planet, any liquid water at the surface would rapidly evaporate or freeze, so evidence of persistent surface water in the past is also evidence for a more clement past climate.

Malin and Edgett estimate that the volume of material in the delta-like fan is about one-fourth the volume of what was removed by the cutting of the upstream channels. Their analysis draws on information from Mars Global Surveyor’s laser altimeter and from cameras on Mars Odyssey and NASA’s Viking Orbiter, as well as images from the Mars Orbiter Camera.

“Because the debris in this fan is now cemented, it shows that some sedimentary rocks on Mars were deposited by water,” Edgett said. “This has been suspected, but never so clearly demonstrated before.”

The camera on Mars Global Surveyor has returned more than 155,000 pictures since the spacecraft began orbiting Mars on Sept. 12, 1997. Still, its high-resolution images cover only about three percent of the planet’s surface. Information about Mars Global Surveyor is available on the Internet at http://mars.jpl.nasa.gov/mgs.

JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA’s Office of Space Science in Washington. JPL’s industrial partner is Lockheed Martin Space Systems, Denver, which developed and operates the spacecraft. Malin Space Science Systems and the California Institute of Technology built the Mars Orbiter Camera. Malin Space Science Systems operates the camera from facilities in San Diego.

Original Source: NASA/JPL News Release

Image credit: ESA

The European Space Agency’s mission to Mars, Mars Express, is right on schedule to arrive at the Red Planet on December 25, 2003. The British-built Beagle 2 lander will also reach Mars the same day, but it will be released from Mars Express on December 19. Beagle 2 doesn’t have any propulsion system of its own, so it’s critical that Mars Express releases it on the right trajectory. It will plunge through Mars’ atmosphere, deploy a parachute, and then land on the surface with the help of an airbag. Assuming everything went well, it will then be able to start examining rocks searching for evidence of life.

Europe’s mission to the Red Planet, Mars Express, is on schedule to arrive at the planet on Christmas Day, 2003.

The lander, Beagle 2, is due to descend through the Martian atmosphere and touch down also on 25 December.

Mars Express is now within 20 million kilometres of the Red Planet and the next mission milestone comes on 19 December, when Mars Express will release Beagle 2. The orbiter spacecraft will send Beagle 2 spinning towards the planet on a precise trajectory.

Into orbit
Beagle has no propulsion system of its own, so it relies on correct aiming by the orbiter to find its way to the planned landing site, a flat basin in the low northern latitudes of Mars.

ESA engineers will then fire the orbiter’s main engine in the early hours of 25 December to put Mars Express into orbit around Mars (called Mars Orbit Insertion, or MOI).

Landing
When Beagle 2 begins its descent, it will be slowed by friction with the Martian atmosphere. Nearer to the surface, parachutes will deploy and large gas-filled bags will inflate to cushion the final touchdown. Beagle 2 should bounce to a halt on Martian soil early on Christmas morning.

The first day on Mars is important for the lander because it has only a few hours to collect enough sunlight with its solar panels to recharge its battery.

Waiting for signal
We then have to wait for the radio ‘life’ signal from Beagle 2, relayed through the US Mars Odyssey spacecraft, to see if the probe has survived the landing. This could take hours or even days.

If nothing is received on Christmas morning, the UK Jodrell Bank Telescope will search for the faint radio signal from Beagle 2 in the evening. The Mars Express orbiter can also search for the lander but, because of its orbit, it will not be in place to do this until early January.

If all goes well, Mars Express and Beagle 2 will then begin their main mission – trying to answer the questions of whether there has been water, and possibly life, on Mars.

Original Source: ESA News Release

Image credit: NASA/JPL

Mars has the largest volcano, the deepest canyon, and it’s got the biggest sand dunes. Several conditions on the Red Planet, including its low gravity, air pressure and sand probably contribute to the gigantic sand dunes that can form there. Dunes have been seen by the Mars Global Surveyor which reach twice as tall as they get on Earth. The Mars Exploration Rovers, currently on track to reach Mars in early 2004 will have cameras on board that may help scientists take a closer look at the sand that makes up these gigantic dunes.

Mars is kind of like Texas: things are just bigger there. In addition to the biggest canyon and biggest volcano in the solar system, Mars has now been found to have sand ripples twice as tall as they would be on Earth.

Initial measurements of some of the Red Planet’s dunes and ripples using stereo-images from the Mars Orbiter Camera onboard the Mars Global Surveyor have revealed ripple features reaching almost 20 feet high and dunes towering at 300 feet.

One way to imagine the taller dimension of ripples on Mars is to visualize sand ripples on Earth, then stretch out the vertical dimension to double height, without changing the horizontal dimension.

“They do seem higher in relation to ripples on Earth,” said Kevin Williams of the Smithsonian National Air and Space Museum. Williams will be presenting this latest insight into the otherworldly scale of Marscapes on Monday, Nov. 3 at the annual meeting of the Geological Society of America in Seattle, WA.

Ripples are common on Mars and usually found in low-lying areas and inside craters, says Williams. On Earth they tend to form in long parallel lines from sand grains being pushed by water or air at right angles to the ripple lines. Dunes, on the other hand, are formed when grains of sand actually get airborne and “saltate” (a word based on the Latin verb “to jump”). That leads to cusp-shaped, star-shaped, and other dune arrangements that allow materials to pile sand much higher.

How exactly Martian dunes and ripples form is still unknown, says Williams, since the images from space give us no clues to the grain sizes or whether they are migrating or moving in any way. Though there are Viking spacecraft images from almost 30 years ago to compare with, the images do not have the resolution to confirm whether ripples have moved much in that time. For now, the dimensions of ripple-forms on Mars are the only indications of whether they are large ripples or small dunes. Williams’ results came about from the advantageous combination of image parameters to get the first height measurements of these ripple-like features at the limit of image resolution.

According to Williams, it’s likely the doubled heights of Mars ripples relative to their spacing is made possible by the same thing that makes Mars’ volcanoes so tall: lower gravity. With about one-third the gravity of Earth, sand, silt, and dust can theoretically stack up higher before gravity causes a slope failure.

However, other differences could play roles in making these large piles of sand as well. “It could also be from different wind speeds, air densities or other factors,” said Williams. Mars has a perennially subfreezing, very thin atmosphere in which global dust storms have been known to obscure the surface from view.

The study of Mars dunes and ripples has been underway since Viking spacecraft images of Mars first revealed such features in the late 1970s and early 1980s, says Williams. The primary difficulty of the work continues to be in discerning the close-up details, like the exact heights of features and grain sizes. As with dunes and ripples on Earth, these wind-blown features could reveal a lot about local and regional weather and wind currents ? if more was known about ripple and dune building under the very un-Earthlike conditions of Mars.

So far the only close-encounters humans have ever had with Martian dunes were with the Viking Landers and the Pathfinder mission, which sent the Sojourner rover trundling among Martian boulders. “There were some small dunes in the area of Pathfinder,” Williams said.

There are also likely to be ripples or small dunes within range of the far more mobile Mars Exploration Rovers now enroute to the Red Planet, Williams said. The Mars Exploration Rovers, Spirit and Opportunity, are larger and will be able to travel much further than Sojourner, making it more likely they will be taking a closer look at ripples as well as other geological features of Mars.

Original Source: Geological Society of America News Release

Image credit: NASA

A team of scientists have traveled to one of the driest places on Earth to help understand why past missions to Mars have failed to detect any life in the soil. The Atacama Desert is located in a region of Chile which is blocked on both sides by high mountain ranges, so it’s incredibly dry. The scientists have studied the soil and realized that organic material is there, it’s just so minimal that the instruments on board the Viking lander, which visited Mars in the 1970s, wouldn’t have been able to sense them. More sophisticated instruments should be installed on future missions to find evidence of life.

A team of scientists from NASA, the Universidad Nacional Autonoma de Mexico, Louisiana State University and several other research organizations has discovered clues from one of Earth’s driest deserts about the limits of life on Earth, and why past missions to Mars may have failed to detect life.

The results were published this week in Science magazine in an article entitled “Mars-like Soils in the Atacama Desert, Chile, and the Dry Limit of Microbial Life.”

NASA’s Viking missions to Mars in the 1970s showed the martian soil to be disappointingly lifeless and depleted in organic materials, the chemical precursors necessary for life. Last year, in the driest part of Chile’s Atacama Desert, the research team conducted microbe-hunting experiments similar to Viking’s, and no evidence of life was found. The scientists called the finding “highly unusual” in an environment exposed to the atmosphere.

“In the driest part of the Atacama, we found that, if Viking had landed there instead of on Mars and done exactly the same experiments, we would also have been shut out,” said Dr. Chris McKay, the expedition’s principal investigator, who is based at NASA Ames Research Center, Moffett Field, Calif. “The Atacama appears to be the only place on Earth Viking would have found nothing.”

During field studies, the team analyzed Atacama’s depleted Mars-like soils and found organic materials at such low levels and released at such high temperatures that Viking would not have been able to detect them, said McKay, who noted that the team did discover a non-biological oxidative substance that appears to have reacted with the organics — results that mimicked Viking’s results.

“The Atacama is the only place on Earth that I’ve taken soil samples to grow microorganisms back at the lab and nothing whatsoever grew,” said Dr. Fred A. Rainey, a co-author from Louisiana State University, who studies microorganisms in extreme environments.

According to the researchers, the Atacama site they studied could serve as a valuable testbed for developing instruments and experiments that are better tailored to finding microbial life on Mars than the current generation. “We think Atacama’s lifeless zone is a great resource to develop portable and self-contained instruments that are especially designed for taking and analyzing samples of the martian soil,” McKay said.

More sophisticated instruments on future sample-return Mars missions are a necessity if scientists are to avoid contaminating future martian samples, McKay noted. “We’re still doing the first steps of instrument development for Mars.” Recently, researchers have developed a method to extract DNA from soil without humans getting involved in processing the data, which is “a step in the right direction,” according to McKay.

The reason Chile’s Atacama Desert is so dry and virtually sterile, researchers say, is because it is blocked from moisture on both sides by the Andes mountains and by coastal mountains. At 3,000 feet, the Atacama is 15 million years old and 50 times more arid than California’s Death Valley. The scientists studied the driest part of the Atacama, an area called the ‘double rain shadow.’ During the past four years, the team’s sensor station has recorded only one rainfall, which shed a paltry 1/10 of an inch of moisture. McKay hypothesizes that it rains in the arid core of the Atacama on average of only once every 10 years.

The Atacama research was funded by NASA’s Astrobiology Science and Technology for Exploring Planets program, by Louisiana State University, the National Science Foundation and by several other organizations.

The article was also authored by Dr. Rafael Navarro-Gonzalez, Dr. Paola Molina and Dr .Jose de la Rosa from the Universidad Nacional Autonoma de Mexico, Mexico City, MX; Danielle Bagaley, Becky Hollen and Alanna Small, Louisiana State University, Baton Rouge, LA.; Dr. Richard Quinn, the SETI Institute, Mountain View, Calif.; Dr. Frank Grunthaner, NASA Jet Propulsion Laboratory, Pasadena, Calif.; Dr. Luis Caceres, Instituto del Desierto y Departameno de Ingenieria, Quimica; and Dr. Benito Gomez-Silva, Instituto del Desierto y unidad de Bioquimica, Universidad de Antofagasta, Antofagasta, Chile.

For images of the field experiments, please go to: http://www.sciencemag.org

Original Source: NASA News Release