Category: Missions

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Remember the movies of clouds floating above the Phoenix Lander? Further study with the lander’s Lidar instrument has detected snow falling from Martian clouds. “The clouds are composed of ice crystals, and some of the crystals are large enough to fall through the atmosphere,” said Jim Whiteway, lead scientist for the Meteorological Station on Phoenix. Whiteway and several researchers shared recent findings from Phoenix at a press briefing today. “So snow is falling from the clouds and we are going to be watching very closely over the next month for evidence that the snow is actually landing on the surface. This is a very important factor in the hydrological cycle on Mars, with the exchange of water between the surface and the atmosphere.”

“Nothing like this view has ever been seen on Mars,” Whiteway added.

From Phoenix images and data, scientists have observed water condensing in the atmosphere. In recent weeks, as the temperatures fall in onset of winter on Mars’ northern plains, frost, ground fog and clouds are prevalent. “This is now occurring every night,” said Whiteway. “The Lidar is able to probe the inner structure of the clouds. It emits pulses of light upward into the atmosphere and detects what is scattered back. The laser emits pulses of light 100 times per second, so if you were standing beside the lander looking upward, you’d see a continuous green beam.” Data and images of the beam show bright spots in beam is where it is reflecting off ice crystals, and also where it reflects off clouds, a few miles above the surface.

The snow starts falling from a height of 4 km and fall down to 2 km. At that point the observations stopped, as they were initially set up for a limited amount of time. Further observations will be done to see if the snow is actually falling down to the surface of the planet.

Other experiments with Martian soil have provided evidence of past interaction between minerals and liquid water. Two different instruments have detected calcium carbonate and clays. On Earth, these form only in the presence of liquid water.

How much calcium carbonate or clays are in the soil hasn’t been fully quantified yet, said Bill Boynton, lead scientist for the TEGA Instrument (Thermal and Evolved Gas Analyzer) But at least 3-6 per cent of the soil is calcium carbonate, and about 1 per cent is clay. There were suspicions of carbonates in Mars soil, and now both the TEGA and the MECA instruments have verified their presence.

Both TEGA, and the microscopy part of MECA, have also turned up hints of a clay-like substance. “We are seeing smooth-surfaced, platy particles with the atomic-force microscope, not inconsistent with the appearance of clay particles,” said Michael Hecht, MECA lead scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

However, finding perchlorates in the soil leads to somewhat of a contradiction, as perchlorates would be sensitive to any water present. If large amounts of water were present in the past, the perchlorates should have dissolved. But they didn’t.

Another clue to the Mars soil puzzle is the dryness of the soil. The lander’s thermal and conductivity probe has indicated the soil is extremely dry around the lander, even though just under the surface, ice is present. “The dryness of the soil is a mystery here,” said Phoenix principal investigator Peter Smith. “We’re wondering if the perchlorate is absorbing or sucking up the water. We say dry because there aren’t any thin films of liquid water mixed with salts in the soil.” If percholate are mixed with water, brines could form, but the scientists have not seen evidence of a brine or remnants of a brine with cameras on board Phoenix. Perchlorates, however, are useful to microbes, which can use it as an energy source. “It’s an Interesting material to find on Mars, and there will be more research coming to find out what it might mean on Mars,” said Smith.

Another finding discussed was the pH levels of the soil. Hecht said the pH of the soil has been determined to be 8.3, which is lower than initially thought. Hecht said this is almost exactly the pH of ocean water on Earth, and the calcium carbonate may be responsible for this level of pH.

Hecht also discussed the unique images from the microscopes on board Phoenix. The first image, shows the soil is mostly composed of fine orange particles, and also contains larger grains, about a tenth of a millimeter in diameter, and of various colors. The soil is sticky, keeping together as a slab of material on the supporting substrate even when the substrate is tilted to the vertical.

The fine orange grains are at or below the resolution of the Optical Microscope. Mixed into the soil is a small amount – about 0.5 percent – of white grains, possibly of a salt. The larger grains range from black to almost transparent in appearance. At the bottom of the image, the shadows of the Atomic Force Microscope (AFM) beams are visible. This image is 1 millimeter x 2 millimeters.

The second image shows a cluster of colored particles. “The reason they are all clustered like that is because they are strongly magnetic,” said Hecht. “All the fine red stuff has fallen off leaving all these little “Easter eggs” of all different colors and shapes. The particles are rounded because they’ve been tumbled by the wind across the sand and they’ve been polished. You also see a lot of angular particles that are clear, that are very white as if they are salts. So we can start to see the different animals in the zoo of Martian mineralogy.” Phoenix’s atomoic force microscope will be used in the coming weeks, and Hecht said the team should be able to provide a catalog of different particles found in these images.

Source: Phoenix new conference, press release

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The robotic arm on NASA’s Phoenix Mars Lander slid a rock out of the way during the mission’s 117th Martian day (Sept. 22, 2008) in order to take a look at the soil underneath the rock, and to see at what depth the subsurface ice was under the rock. The lander’s Surface Stereo Imager took this image later the same day, showing the rock, called “Headless,” after the arm pushed it about 40 centimeters (16 inches) from its previous location. “The rock ended up exactly where we intended it to,” said Matt Robinson of NASA’s Jet Propulsion Laboratory, robotic arm flight software lead for the Phoenix team. And what was underneath the rock? Take a look:

It’s hard to tell, exactly since the ground was disturbed from the moving. Some white material appears to be where the rock used to sit, but the Phoenix science team will have to study the area more closely. Look for official word from the team soon. It looks from this second image as though the thermal and conductivity probe was stuck in the ground a few times around the rock, searching for clues of any water molecules in the soil (look for the two separate marks left by the probe just to the right of the trench.)

Also in recent days, the two Phoenix cameras took portraits of each other. Above is the Robotic Arm Camera (RAC) and below is the the Surface Stereo Imager:

Source: Phoenix Gallery

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Opportunity, the intrepid Mars Exploration Rover, is going to put the pedal to the metal and head out for a crater nearly 12 kilometers (7 miles) away. That would match the distance the rover has traveled since landing in 2004. But the call of the unknown is compelling the rover science team to make the attempt. “We may not get there, but it is scientifically the right direction to go anyway,” said Steve Squyres, principal investigator for the science instruments on Opportunity and its twin rover, Spirit. For an “aging” rover (what age is 4 in rover years?), this might be setting the bar pretty high. But maybe it’s the journey and not the destination.

“This is a bolder, more aggressive objective than we have had before,” said John Callas, the project manager the rovers. “It’s tremendously exciting. It’s new science. It’s the next great challenge for these robotic explorers.”

“This crater is staggeringly large compared to anything we’ve seen before.” The crater, named Endeavour, is 22 kilometers (13.7 miles) across. “I would love to see that view from the rim,” Squyres said. “But even if we never get there, as we move southward we expect to be getting to younger and younger layers of rock on the surface. Also, there are large craters to the south that we think are sources of cobbles that we want to examine out on the plain. Some of the cobbles are samples of layers deeper than Opportunity will ever see, and we expect to find more cobbles as we head toward the south.”

The rover team estimates Opportunity may be able to travel about 110 yards each day it is driven toward the Endeavour crater. Even at that pace, the journey could take two years. But why not go for it, and see how long the rovers can last?

Opportunity, like Spirit, is well past its expected lifetime on Mars, and might not keep working long enough to reach the crater. However, two new resources not available during the 4-mile drive toward Victoria Crater in 2005 and 2006 are expected to aid in this new trek.

One is imaging from orbit of details smaller than the rover itself, using the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter, which arrived at the Red Planet in 2006.

“HiRISE allows us to identify drive paths and potential hazards on the scale of the rover along the route,” Callas said. “This is a great example of how different parts of NASA’s Mars Exploration Program reinforce each other.”

Also, Opportunity now has a better “brain” for driving across the the plains of Mars. A new version of flight software uplinked to Opportunity and Spirit in 2006, boosts their ability to autonomously choose routes and avoid hazards such as sand dunes.

During its first year on Mars, Opportunity found geological evidence that the area where it landed had surface and underground water in the distant past. The rover’s explorations since have added information about how that environment changed over time. Finding rock layers above or below the layers already examined adds windows into later or earlier periods of time.

Source: JPL

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Ever wondered what might crawl out from under a rock on Mars? The Phoenix lander is going to attempt to find out today by trying to nudge a rock aside today with its robotic arm to see what might be underneath. Engineers have developed a plan to try moving a rock on the north side of the lander. This rock, roughly the size and shape of a VHS videotape, is called “Headless.” Even though the Phoenix mission has been extended for a second time – the mission is now on through December, the team feels like it’s time to pull out all the stops and do as much work as possible. “We’re getting towards fall in the northern plains of Mars and our sun is dropping lower day by day,” said mission principal investigator Peter Smith on NPR’s Science Friday. “Our days are getting precious.” So, even though Phoenix’s robotic arm was not designed to move rocks, the team wants to give it a shot. “The appeal of studying what’s underneath is so strong we have to give this a try,” said Michael Mellon, a Phoenix science team member at the University of Colorado, Boulder.

“We don’t know whether we can do this until we try,” said Ashitey Trebi Ollennu, a robotics engineer at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The idea is to move the rock with minimum disturbance to the surface beneath it. You have to get under it enough to lift it as you push it and it doesn’t just slip off the scoop.”

The lander receives commands for the whole day in the morning, so there’s no way to adjust in mid-move if the rock starts slipping. Phoenix took stereo-pair images of Headless to provide a detailed three-dimensional map of it for planning the arm’s motions. On Saturday, Sept. 20, the arm enlarged a trench close to Headless. Commands sent to Phoenix Sunday evening, Sept. 21, included a sequence of arm motions for today, intended to slide the rock into the trench.

If the technique works, the move would expose enough area for digging into the soil that had been beneath Headless.

The scientific motive is related to a hard, icy layer found beneath the surface in trenches that the robotic arm has dug near the lander. Excavating down to that hard layer underneath a rock might provide clues about processes affecting the ice.

“The rocks are darker than the material around them, and they hold heat,” Mellon said. “In theory, the ice table should deflect downward under each rock. If we checked and saw this deflection, that would be evidence the ice is probably in equilibrium with the water vapor in the atmosphere.”

An alternative possibility, if the icy layer were found closer to the surface under a rock, could by the rock collecting moisture from the atmosphere, with the moisture becoming part of the icy layer.

Source: JPL

The Phoenix Mars Lander is working as fast as it can to dig and deliver as many samples as possible before the power produced by Phoenix’s solar panels declines due to the end of the Martian summer. This image, from Sol 107 (Sept. 12 here on Earth), shows the lander has delivered a sample of soil from the “Snow White” trench to the Wet Chemistry Laboratory. A small pile of soil is visible on the lower edge of the second cell from the top. This deck-mounted lab is part of Phoenix’s Microscopy, Electrochemistry and Conductivity Analyzer (MECA).

The Wet Chemistry Laboratory mixes Martian soil with an water-based solution from Earth as part of a process to identify soluble nutrients and other chemicals in the soil. Preliminary analysis of this soil confirms that it is alkaline, and composed of salts and other chemicals such as perchlorate, sodium, magnesium, chloride and potassium. This data validates prior results from that same location, said Michael Hecht of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., the lead scientist for MECA.

In the coming days, the Phoenix team will also fill the final four of eight single-use ovens on another soil-analysis instrument, the Thermal and Evolved Gas Analyzer, or TEGA.

Source: Phoenix news site

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Did Mars once have a thick atmosphere? Could the climate on the Red Planet have supported water and possibly life in the past? These are the questions NASA hopes to answer in great detail with the newest orbiter mission to Mars. Called the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, the $485 million mission is scheduled for launch in late 2013. MAVEN is part of the Mars Scout Program, which is designed to send a series of small, low-cost, principal investigator-led missions to the Red Planet. The Phoenix Mars Lander was the first spacecraft selected in this program. “This mission will provide the first direct measurements ever taken to address key scientific questions about Mars’ evolution,” said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington.

Evidence from orbit and the planet’s surface points to a once denser atmosphere on Mars that supported the presence of liquid water on the surface. As part of a dramatic climate change, most of the Martian atmosphere was lost. MAVEN will make definitive scientific measurements of present-day atmospheric loss that will offer clues about the planet’s history.

“The loss of Mars’ atmosphere has been an ongoing mystery,” McCuistion said. “MAVEN will help us solve it.”

The science team will be led from the University of Colorado at Boulder, and its Laboratory for Atmospheric and Space Physics. The principal investigator for the mission is Bruce Jakosky from UC Boulder. “We are absolutely thrilled about this announcement,” said Jakosky. “We have an outstanding mission that will obtain fundamental science results for Mars. We have a great team and we are ready to go.”

Lockheed Martin of Littleton, Colo., will build the spacecraft based on designs from NASA’s Mars Reconnaissance Orbiter and 2001 Mars Odyssey missions.
MAVEN was evaluated to have the best science value and lowest implementation risk from 20 mission investigation proposals submitted in response to a NASA Announcement of Opportunity in August 2006.

After arriving at Mars in the fall of 2014, MAVEN will use its propulsion system to enter an elliptical orbit ranging 90 to 3,870 miles above the planet. The spacecraft’s eight science instruments will take measurements during a full Earth year, which is roughly equivalent to half of a Martian year.
MAVEN’s instrument suites include a remote sensing package that will determine global characteristics of the upper atmosphere, and the spacecraft will dip to an altitude of 80 miles above the planet. A particles and fields payload contains six instruments that will characterize the solar wind, upper atmosphere and the ionosphere – a layer of charged particles very high in the Martian atmosphere.

The third instrument suite, a Neutral Gas and Ion Mass Spectrometer will measure the composition and isotopes of neutral and charged forms of gases in the Martian atmosphere

During and after its primary science mission, the spacecraft may be used to provide communications relay support for robotic missions on the Martian surface.

More information on MAVEN.

Sources: NASA, UC Boulder

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Not only has the Phoenix Mars Lander photographed several dust devils dancing across the arctic plain this week, but sensors that monitor various atmospheric conditions around the lander detected a dip in air pressure as one of the whirlwinds passed nearby. This is the first time dust devils have been detected in Phoenix images. Scientists believe the increasing difference between daytime high temperatures (about -30C) and night lows (around -90C) is the key to the formation of the dust devils. Click here to download a dust devil movie created from the images.

The Surface Stereo Imager camera on Phoenix took 29 images of the western and southwestern horizon on Sept. 8, during mid-day hours of the lander’s 104th Martian day. The next day, after the images had been transmitted to Earth, the Phoenix science team noticed a dust devil right away.

“It was a surprise to have a dust devil so visible that it stood with just the normal processing we do,” said Mark Lemmon of Texas A&M University, College Station, lead scientist for the stereo camera. “Once we saw a couple that way, we did some additional processing and found there are dust devils in 12 of the images.”

At least six different dust devils appear in the images, some of them in more than one image. They range in diameter from about 2 meters (7 feet) to about 5 meters (16 feet).

The Phoenix team is not worried about any damage to the spacecraft from these swirling winds. “With the thin atmosphere on Mars, the wind loads we might experience from dust devil winds are well within the design of the vehicle,” said Ed Sedivy, Phoenix program manager at Lockheed Martin Space Systems Company, Denver, which made the spacecraft. “The lander is very rigid with the exception of the solar arrays, which once deployed, latched into position and became a tension structure.”

Phoenix monitors air pressure every day, and on the same day the camera saw dust devils, the pressure meter recorded a sharper dip than ever before. The change was still less than the daily change in air pressure from daytime to nighttime, but over a much shorter time.

“Throughout the mission, we have been detecting vortex structures that lower the pressure for 20 to 30 seconds during the middle part of the day,” said Peter Taylor of York University, Toronto, Canada, a member of the Phoenix science team. “In the last few weeks, we’ve seen the intensity increasing, and now these vortices appear to have become strong enough to pick up dust.”

The same day as the dust devils were seen, the photographed swinging of Phoenix’s telltale wind gauge indicated wind speeds exceeding 5 meters per second (11 miles per hour). Download a movie of the telltail wind gauge.

Images from spacecraft orbiting Mars had previously indicated that dust devils exist in the region where Phoenix landed.

“We expected dust devils, but we are not sure how frequently,” said Phoenix Project Scientist Leslie Tamppari of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “It could be they are rare and Phoenix got lucky. We’ll keep looking for dust devils at the Phoenix site to see if they are common or not.”

The dust devils that Phoenix has observed so far are much smaller than dust devils that NASA’s Mars Exploration Rover Spirit has photographed much closer to the equator.

Source: Phoenix news site.

Clumps of material have adhered to the legs of the Phoenix Mars Lander, and the clumps continue to change and grow. The science team has discussed various possible explanations for these clumps. One suggestion is that they may have started from a splash of mud if Phoenix’s descent engines melted icy soil during the landing. Another is that specks of salt may have landed on the strut and began attracting atmospheric moisture that freezes and accumulates. The clumps are concentrated on the north side of the strut, usually in the shade, so their accumulation could be a consequence of the fact that condensation favors colder surfaces. Below, compare images taken on September 1, 2008, or the 97th Martian Day or sol, since landing with another image taken about three months earlier, on Sol 8.

Phoenix’s Robotic Arm Camera took both images. The top image from Sol 97 was taken at about 4 a.m. local solar time. The view in this Sol 97 image is southward. Illumination is from the early morning sun above the northeastern horizon. This is quite different from the illumination in the Sol 8 image, bottom which was taken in mid-afternoon.

The two images also show a contrast in the flat, smooth patch of exposed ice underneath the lander. Phoenix team members believe the ice was exposed from the spacecraft’s thrusters as it landed. In the latest image, the patches of ice exposed underneath the lander seem to be partly covered by darker material left behind as ice vaporizes away. The flat patch in the center of the image has the informal name “Holy Cow,” based on researchers’ reaction when they saw the initial image of it.

Source: Phoenix Gallery

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The Mars Exploration Rovers are now tweeting on Twitter, and Opportunity recently shared what she’s been doing since climbing out of Victoria crater via a shadow self portrait. After seeing a one-time electrical spike on Opportunity’s left front wheel, mission managers decided to have the rover climb out of the crater and get back on level ground. Opportunity is now examining some fist sized rocks, or cobbles, that might be ejecta from far away craters. Spirit, over on the other side of the Red Planet is weathering out the end of the southern hemisphere Martian winter. Another Twitter report from the rovers said that Spirit’s solar array energy is now up slightly from 235 to 245 watt hours. Power levels will have to rise a little more before Spirit can resume exploring actively.

Spirit has had to park on a north facing tilt in order to gather as much sunlight, and the image above shows the tilt. In the latest rover flight director video report, rover driver Scott Maxwell said the team is keeping an eye on the weather near Spirit’s, location watching for any rise in atmospheric dust. Dust has gathered on the rover’s solar panels, and any additional dust would hamper power levels as well. But so far everything is looking good, and Martian skies were actually clearer this past week.

Both rovers have been operating for more than 1,600 Martian sols, or days on Mars. A sol on Mars in about 40 minutes longer than an Earth day.