Artists rendition of Phoenix on Mars. Credit: NASA/JPL
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Starting today, the Mars Odyssey orbiter will be listening once again for the Phoenix Mars Lander, lending an ear to hear if Phoenix has come back to life. Until May 21,Odyssey will listen for a signal from Phoenix during 61 flights over the lander’s site on Mars’ northern arctic region. Earlier attempts to detect a transmission from the lander — totaling 150 overflights in January, February and April – were not successful.
NASA decided to add another round of listening sessions that weren’t originally scheduled.
“To be thorough, we decided to conduct this final session around the time of the summer solstice, during the best thermal and power conditions for Phoenix,” said Chad Edwards, chief telecommunications engineer for the Mars Exploration Program at NASA’s Jet Propulsion Laboratory.
Phoenix quit communicating with Earth in November, 2008, and since that time endured a long and fierce Mars winter, where it was likely encased in CO2 ice in temperatures under -150 C. The solar arrays may have cracked and fallen off the vehicle, and the electronics probably became brittle and broke in the severe cold, so the wiring boards probably are nonfunctional.
Phoenix worked superbly for five months before reduced sunlight caused energy to become insufficient to keep the lander functioning. The solar-powered robot was not designed to survive through the dark and cold conditions of a Martian arctic winter.
Northern Mars experienced its maximum-sunshine day, the summer solstice, on May 12 (Eastern Time; May 13, Universal Time), so the sun will be higher in the sky above Phoenix during the fourth listening campaign than during any of the prior ones. Still, expectations of hearing from the lander remain low.
But nobody is ready to give up just yet.
No word yet from the Phoenix Mars Lander and, really, mission managers don’t expect to hear from the lander. But that doesn’t mean they aren’t trying. Teams are currently attempting to make contact, with another — and final — series of attempts that may occur next month.
“We haven’t heard a peep since late 2008, when a dust storm combined with the onset of winter to end the mission,” said Mark Lemmon from Texas A&M University, who worked with Phoenix’s camera. “But if Phoenix did survive, a revived mission could uncover some of the climate processes in the area around Mars’ North Pole, where most of the water seems to be.”
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Last contact with Phoenix was back in October 2008, and the teams that worked with the lander are holding out hope that some of the electronics on board survived the severe Martian winter, which dwarfs anything seen on Earth (even the Snowmageddons and Snowpocalypses). Temperatures fall to minus-180 degrees for months at a time and carbon dioxide ice likely engulfed the Phoenix lander. Still, Lemmon said he is ready to help take more pictures and analyze more data if the Lander can be restored to life.
“Phoenix accomplished its mission,” he said, “and it was never designed to survive a Martian winter. In winter, heavy amounts of carbon dioxide frost may have accumulated on its solar panels and it is possible they broke off. Without those panels, which give Phoenix its energy source, it’s pretty much powerless. In addition, other parts may have failed in the extreme cold.”
Phoenix landing site, August, 2009. Credit: NASA/JPL/U of Arizona. Annotations by Phil Stooke
The Phoenix Lander, which landed on Mars May 25, 2008, was designed to dig for soil samples and buried ice near Mars’ North Pole. It also studied Mars’ polar weather.
Phoenix returned more than 30,000 images and made several chemical analyses of the soil above the Martian permafrost. Those analyses found carbonate minerals in the soil, showed that the composition of the soil is near that of Earth’s oceans rather than being acidic, and found perchlorates, which are present in soils in Chile’s Atacama desert on Earth, where they are used as food by some species of bacteria.
Recent images from the Mars Reconnaissance Orbiter show frost in the area around Phoenix’s landing site is now dissipating. Last month, the Mars Odyssey spacecraft, which orbits the planet, made 30 attempts to contact Lander. All failed.
Lemmon says the Lander mission was a success by any measurement.
“The soil samples it dug up show several possible energy sources, such as perchlorates,” he adds, “and that discovery will have a big impact on future plans to explore Mars. The weather information Phoenix returned will be very useful in understanding Mars’ climate, and the discovery of water-ice snowfall near the end of the mission is still amazing.”
A look at the nearly buried wheels on the Spirit rover on Mars. Credit: NASA/JPL
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Not a peep yet from the Phoenix lander. The Mars Odyssey orbiter has completed all 30 relay overflights of the Phoenix landing site that were scheduled for Jan. 18 to 21, and heard nothing from the lander. Additional listening campaigns will be conducted in February and March. NASA has said repeatedly that hearing from the lander would be highly unlikely, as Phoenix was never designed to withstand the Martian arctic winters.
Meanwhile, the outlook isn’t brilliant for the Spirit rover, either.
Efforts to free the rover have barely budged it, and as the Martian autumn approaches, precious sunlight which provides power to the rover is declining each day. As of now, Spirit is tilted the wrong way to generate enough heat to make it through the winter, although the Free Spirit team is working to change the angle of her solar panels.
The rover team has now begun driving Spirit backward as the next technique for attempting to extricate the rover from the sand trap where it is embedded. The first two backward drives produced about 6.5 centimeters (2.6 inches) of horizontal motion and lifted the rover slightly.
However, the right-rear wheel is still non-functional, along with the right-front wheel (even though that wheel came back to life, briefly), and during a recent extrication drive attempt, the left middle wheel stalled. The team is working to get more diagnostic information about that wheel stall. Even with four working wheels, Spirit would have a very difficult path to get out of her predicament.
And rover fans must be continuing to suggest using the rover’s robotic arm to help push Spirit out, because the latest press release about Spirit included some back-of-the-envelope calculations about using the arm for just such an action. They figured out that by pushing with the arm, only about 30 newtons of lateral force could be achieved, while a minimum of several hundreds of newtons would be needed to move the rover. Further, such a technique risks damaging the arm and preventing its use for high-priority science from a stationary rover. The other technique of re-sculpting the terrain and perhaps pushing a rock in front of or behind the left-front wheel was also assessed to be of little to no help and, again, risks the arm. There is also a large risk of accidentally pushing the rock into the open wheel and jamming it.
When asked if he was discouraged about Spirit’s current situation, NASA’s lead scientist for the Mars exploration program, Michael Meyer said, “You gotta be joyful when something that was only supposed to operate for three months lasts over 6 years.” A 3-D view of Opportunity's view as she leaves Marquette Island, created by Stu Atkinson. Image credit: NASA/JPL/ U of Arizona
The Opportunity rover, on the other side of Mars, continues her approximately 7 mile trek to Endeavour Crater. The rover left the rock called Marquette Island on Sol 2122 (Jan. 12, 2010), and has now crossed the 19-kilometer (11.8-mile) odometer mark. Amazing!
There is a relatively fresh impact crater that has been named “Conception,” and Oppy will stop to investigate, having to detour about 250 meters (820 feet) to the south.
Caption: The Phoenix Mars Lander, its backshell and its heatshield are visible within this enhanced-color image of the Phoenix landing site taken on Jan. 6, 2010 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. Image credit: NASA/JPL-Caltech/University of Arizona
Listen up, all you Phoenix lander fans! Beginning Jan. 18, the Mars Odyssey orbiter will start listening for any signs of life from Phoenix, which has been sitting silently on the frozen arctic region of Mars since its last communication in November 2008. The Phoenix team says hearing any radio transmission from the lander is high improbably, but possible. Never say never….
“We do not expect Phoenix to have survived, and therefore do not expect to hear from it. However, if Phoenix is transmitting, Odyssey will hear it,” said Chad Edwards, chief telecommunications engineer for the Mars Exploration Program at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We will perform a sufficient number of Odyssey contact attempts that if we don’t detect a transmission from Phoenix, we can have a high degree of confidence that the lander is not active.”
Odyssey will pass over the Phoenix landing site approximately 10 times each day during three consecutive days of listening this month and two longer listening campaigns in February and March. The listening attempts will continue until after the sun is above the horizon for the full 24.7 hours of the Martian day at the lander’s high-latitude site. During the later attempts in February or March, Odyssey will transmit radio signals that could potentially be heard by Phoenix, as well as passively listening. Phoenix close up from July 2009. Annotated by Phil Stooke.
In the extremely unlikely case that Phoenix survived the winter, it is expected to follow instructions programmed on its computer. If systems still operate, once its solar panels generate enough electricity to establish a positive energy balance, the lander would periodically try to communicate with any available Mars relay orbiters in an attempt to reestablish contact with Earth. During each communications attempt, the lander would alternately use each of its two radios and each of its two antennas.
If Odyssey does hear from Phoenix, the orbiter will attempt to lock onto the signal and gain information about the lander’s status. The initial task would be to determine what capabilities Phoenix retains, information that NASA would consider in decisions about any further steps.
Phoenix landed in May, 2008 and worked for about five months before succumbing to the cold weather. Since then, Phoenix’s landing site has gone through autumn, winter and part of spring. The lander’s hardware was not designed to survive the temperature extremes and ice-coating load of an arctic Martian winter.
But who knows; our Mars spacecraft seemingly have a tendency to surprise us…
Phoenix landing site in Dec. 2008 and August 2009. Credit: NASA/JPL/ U of Arizona; annotations by Phil Stooke
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I was just thinking of the Phoenix lander earlier this week, wondering if our little buddy was surviving the Martian winter when, boom: via Twitter came this:
@MarsPhoenix “Spring has sprung in the north hemi(sphere) of Mars! Team is waiting for longer daylight hours, around mid-Jan., to ‘listen’ for our lander.”
Then, via another Tweet from @doug_ellison, (Doug Ellision) I found out the folks at Unmannedspaceflight.com have been thinking about the Phoenix lander, too. Phil Stooke from the UMSF crew had searched for Phoenix in the latest images released by the HiRISE camera on board the Mars Reconnaissance Orbiter, taken in August 2009 and found of glimmer of hope the lander was still visible among the CO2 frost and “snow.” See the comparison above of the landing site from Dec. 2008 to August 2009. Then Emily Lakadawalla of the Planetary Society Blog took things one step further and made a little “movie” of HiRISE images of Phoenix during the different seasons on Mars (check out her extensive post here.) Hope springs eternal for many of us as to whether we’ll ever hear from Phoenix again, and time will only tell. But its nice to know there were lots of us with Phoenix on the brain this week; kind of a shared experience! (except everyone else did all the work….) See below for more closeups of Phoenix’s winter surroundings from UMSF.
Phoenix landing site, August, 2009. Credit: NASA/JPL/U of Arizona. Annotations by Phil Stooke
Phil wrote on UMSF that it took him several tries to match up the landing site from the two different HiRISE images. “When the two sides of this comparison are blinked a thousand features match up, not just a dozen. This is a lesson to people searching for Mars Polar lander – it’s easy to be fooled! … The parachute and backshell are invisible, the heatshield almost so, but the lander’s clear.”
And below is one of just the lander from July 2009. Unfortunately, HiRISE has been unable to take any recent images of Phoenix or any other location on Mars because of MRO being in an extended safe mode. It went into safe mode over 9 weeks ago, and mission engineers have yet to determine the cause. They are playing it safe and want to get to the root cause, since this has happened four times over the course of the mission. Latest word reported in the Arizona Star is that if the system reboots itself enough times, the memory of the main computer could be reset, and basically wiped. That would be bad. “Engineers are now working to create a safeguard against that worst-case scenario as well as finding the cause of the mysterious voltage signals,” the Star said.
Phoenix close up from July 2009. Annotated by Phil Stooke.
The Telltale instrument on the Phoenix lander. Credit: University of Aarhus.
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On board the plucky little Phoenix Mars lander was an even pluckier and littler device called the Telltale. It measured, for the first time, wind speeds and directions at the Mars polar region. Scientists have now been able to summarize the results from the Telltale, and presented their findings at the European Planetary Science Conference in Potsdam, Germany. They shared some unexpected new findings about the weather on Mars.
“Telltale has given us a wealth of information about the local Martian wind velocities and directions. At the Phoenix landing site, we were able to see meteorological changes caused by interactions between the dynamic north pole, where there are ever changing evaporation processes, and the Martian atmosphere,” said Dr. Haraldur Gunnlaugsson. Artists rendition of Phoenix on Mars. Credit: NASA/JPL
As you recall, Phoenix landed in the North polar region of Mars on May 25, 2008 and operated successfully for about 5 Earth months, or 151 Martian sols. The Telltale device consisted of a lightweight tube suspended on top of a meteorological mast, roughly two meters above the local surface. The device had to be sensitive enough to detect very light breezes, but also be able to withstand the violent vibrations during the mission launch. After landing on Mars, Phoenix’s onboard camera continuously imaged the deflection of the tube in the wind, taking more than 7,500 images during the mission.
The astronomers/meteorologists found the wind speeds and directions varied as the seasons changed. Easterly winds of approximately 15-20 kilometers per hour prevailed during the Martian mid-summer, but when autumn approached, the winds increased and switched to come predominantly from the West. While these winds appeared to be dominated by turbulence, the highest wind speeds recorded of up to nearly 60 kilometers per hour coincided with the passing of weather systems, when also the number of dust devils increased by an order of magnitude.
Mars is typically a rather windy place and learning more about the planet’s climatic conditions will contribute to the understanding of the Martian water cycle and the identification of areas on the red planet that could sustain life. Local wind measurements by the Telltale instrument, amended with daily images of the whole northern hemisphere by the Mars Reconnaissance Orbiter spacecraft, have allowed astronomers to gain much deeper information on weather systems on Mars.
“We’ve seen some unexpected night-time temperature fluctuations and are starting to understand the possible ways dust is put into suspension in the Martian atmosphere. For example, we could see that some of the dust storms on Mars do not require the existence of high winds,” said Dr Gunnlaugsson.
This mosaic assembled from Phoenix images show the spacecraft's three landing legs. Splotches of Martian material on the landing leg strut at left could be liquid saline-water. Click for larger version on Spaceflightnow. com Credit: Kenneth Kremer, Marco Di Lorenzo, NASA/JPL/UA/Max Planck Institute and Spaceflightnow.com. Used by permission
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Scientists say that the Arctic region studied by Phoenix lander may be a favorable environment for microbes. Just-right chemistry and periods where thin films of liquid water form on the surface could make for a habitable setting. “Not only did we find water ice, as expected, but the soil chemistry and minerals we observed lead us to believe this site had a wetter and warmer climate in the recent past — the last few million years — and could again in the future,” said Phoenix Principal Investigator Peter Smith of the University of Arizona, Tucson.
The Phoenix science team released four papers today after spending months interpreting the data returned by the lander during its 5-month mission.
The most surprising finding was perchlorate in the Martian soil. This Phoenix finding caps a growing emphasis on the planet’s chemistry, said Michael Hecht of from the Jet Propulsion Laboratory, who led a paper about Phoenix’s soluble-chemistry findings.
“The study of Mars is in transition from a follow-the-water stage to a follow-the-chemistry stage,” Hecht said. “With perchlorate, for example, we see links to atmospheric humidity, soil moisture, a possible energy source for microbes, even a possible resource for humans.”
Perchlorate, which strongly attracts water, makes up a few tenths of a percent of the composition in all three soil samples analyzed by Phoenix’s wet chemistry laboratory. It could pull humidity from the Martian air. At higher concentrations, it might combine with water as a brine that stays liquid at Martian surface temperatures. Some microbes on Earth use perchlorate as food. Human explorers might find it useful as rocket fuel or for generating oxygen. Close up shows splashes of material on lander leg strut. Image: Kenneth Kremer, Marco Di Lorenzo, NASA/JPL/UA/Max Planck Institute. Used by permission.
A paper about Phoenix water studies, led by Smith, cites clues supporting an interpretation that the soil has had films of liquid water in the recent past. The evidence for water and potential nutrients “implies that this region could have previously met the criteria for habitability” during portions of continuing climate cycles, these authors conclude.
Phoenix dug down with its scoop and found ice just under the surface of Mars. “We wanted to know the origin of the ice,” Smith said. “It could have been the remnant of a larger polar ice cap that shrank; could have been a frozen ocean; could have been a snowfall frozen into the ground. The most likely theory is that water vapor from the atmosphere slowly diffused into the surface and froze at the level where the temperature matches the frost point. We expected that was probably the source of the ice, but some of what we found was surprising.”
Evidence that the ice in the area sometimes thaws enough to moisten the soil comes from finding calcium carbonate in soil heated in the lander’s analytic ovens or mixed with acid in the wet chemistry laboratory. Another paper from a team led by University of Arizona’s William Boynton report that the amount of calcium carbonate “is most consistent with formation in the past by the interaction of atmospheric carbon dioxide with liquid films of water on particle surfaces.”
This mosaic of images from the Surface Stereo Imager camera on NASA's Phoenix Mars Lander shows several trenches dug by Phoenix, plus a corner of the spacecraft's deck and the Martian arctic plain stretching to the horizon. Image Credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University
The new reports leave unsettled whether soil samples scooped up by Phoenix contained any carbon-based organic compounds. The perchlorate could have broken down simple organic compounds during heating of soil samples in the ovens, preventing clear detection.
The heating in ovens did not drive off any water vapor at temperatures lower than 295 degrees Celsius (563 degrees Fahrenheit), indicating the soil held no water adhering to soil particles. Climate cycles resulting from changes in the tilt and orbit of Mars on scales of hundreds of thousands of years or more could explain why effects of moist soil are present.
Phoenix launched in August 2007and landed in May, 2008. Phoenix ended communications in November 2008 as the approach of Martian winter depleted energy from the lander’s solar panels.
Data from the Phoenix lander's LIDAR instrument showing precipitation falling on Mars. Credit: Whiteway, et al.
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It snows on Mars. This occurs, at least in the northern arctic region where the Phoenix lander set up camp in 2008. Science teams from Phoenix were able to observe water-ice clouds in the Martian atmosphere and precipitation that fell to the ground at night and sublimate into water in the morning. James Whiteway and his colleagues say that clouds and precipitation on Mars play a role in the exchange of water between the ground and the atmosphere and when conditions are right, snow falls regularly on Mars.
“Before Phoenix we did not know whether precipitation occurs on Mars,” Whiteway said. “We knew that the polar ice cap advances as far south as the Phoenix site in winter, but we did not know how the water vapor moved from the atmosphere to ice on the ground. Now we know that it does snow, and that this is part of the hydrological cycle on Mars.”
Phoenix landed at the north arctic region on Mars (68.22°N, 234.25°E) on May 25th, 2008. On Mars, this was just before the summer solstice. Phoenix operated for 5 months, and was able to observe conditions as the seasons changed from summer to winter, giving science teams an unprecedented look at the planet’s changing weather patterns, including frost and precipitation.
The science team used the light detection and ranging instrument, known as LIDAR, and observed clouds that are similar to cirrus clouds here on Earth.
The LIDAR instrument emits pulses of laser light upward into the atmosphere, and then detects the backscatter from dust and clouds. The researchers were able to observe that water-ice crystals grow large enough to precipitate through the atmosphere at night and sublimate into water in the morning. The water vapor on the ground is then mixed back up through the air by turbulence and convection – reaching a height of about two and a half miles (four kilometers) – before again forming clouds at night.
Movie of clouds on Mars. Credit: NASA/JPL/UofA
Fall streaks in the cloud structure traced the precipitation of ice crystals toward the ground.
“Frost was predicted, but snowfall was quite a welcome surprise,” said Phoenix principal investigator Peter Smith. “In summer there was a lot of dust in the atmosphere. As we neared fall, the dust cleared, and all of a sudden there were water ice clouds forming at about 4 km (2.5 mi.) above the surface. We could see the clouds scud by, moving through the camera field, and once we saw snow coming out of the bottom of a cloud. It was very exciting to watch the daily weather changes. No one has ever had this experience.”
Using the LIDAR, the team could measurement atmospheric dust in the planetary boundary layer (PBL), the lowest part of the atmosphere which is directly influenced by its contact with a planetary surface.
Whiteway and his team said the PBL on Mars is quite interesting. “The PBL on Mars was well mixed, up to heights of around 4 kilometers, by the summer daytime turbulence and convection,” the team wrote in their paper, which is published today in the Journal Science. “The water-ice clouds were detected at the top of the PBL and near the ground each night in late summer after the air temperature started decreasing. The interpretation is that water vapor mixed upward by daytime turbulence and convection forms ice crystal clouds at night that precipitate back toward the surface.”
The clouds didn’t begin forming until around sol 80 or 90 – the number of days from when Phoenix landed on Mars — when air temperatures were cool enough for water vapor in the atmosphere to condense. In the early morning hours on sol 109, the LIDAR observed clouds and precipitation that extended all the way to the ground.
The science team said the clouds and precipitation keep the water confined within the PBL. Eventually, the ice clouds would have persisted within the PBL throughout the daytime, and water ice would have remained deposited on the ground. As the depth of the PBL decreased in late summer, the atmospheric water vapor would decrease, and the process would eventually stop as winter progressed.
