Phoenix (Spacecraft) - A Space Exploration Mission on Mars
Phoenix was a robotic spacecraft on a space exploration mission on Mars under the Mars Scout Program. Mission scientists used instruments aboard the Phoenix lander to search for environments suitable for microbial life on Mars, and to research the history of water there.
The multi-agency program was headed by the Lunar and Planetary Laboratory at the University of Arizona, under the direction of NASA's Jet Propulsion Laboratory. The program was a partnership of universities in the United States, Canada, Switzerland, Denmark, Germany, the United Kingdom, NASA, the Canadian Space Agency, the Finnish Meteorological Institute, Lockheed Martin Space Systems, MacDonald Dettwiler & Associates (MDA) and other aerospace companies. The operational funding for the mission extended through November 10, 2008.
Phoenix is NASA's sixth successful landing on Mars out of the twelve attempts that reached Mars. It is the most recent spacecraft to land successfully on Mars. It is also the first successful landing on a polar region of Mars. The mission was declared concluded on November 10, 2008, after engineers were unable to contact the craft. The lander last made a brief communication with Earth on November 2.
The multi-agency program was headed by the Lunar and Planetary Laboratory at the University of Arizona, under the direction of NASA's Jet Propulsion Laboratory. The program was a partnership of universities in the United States, Canada, Switzerland, Denmark, Germany, the United Kingdom, NASA, the Canadian Space Agency, the Finnish Meteorological Institute, Lockheed Martin Space Systems, MacDonald Dettwiler & Associates (MDA) and other aerospace companies. The operational funding for the mission extended through November 10, 2008.
Phoenix is NASA's sixth successful landing on Mars out of the twelve attempts that reached Mars. It is the most recent spacecraft to land successfully on Mars. It is also the first successful landing on a polar region of Mars. The mission was declared concluded on November 10, 2008, after engineers were unable to contact the craft. The lander last made a brief communication with Earth on November 2.
The mission had two goals. One was to study the geologic history of water, the key to unlocking the story of past climate change. The second was evaluate past or potential planetary habitability in the ice-soil boundary. Phoenix's instruments were suitable for uncovering information on the geological and possibly biological history of the Martian Arctic. Phoenix was the first mission to return data from either of the poles, and contributed to NASA's main strategy for Mars exploration, "Follow the water."
The primary mission was anticipated to last 90 sols (Martian days) - just over 92 Earth days. However, the craft exceeded its expected operational lifetime by a little over two months before succumbing to the increasing cold and dark of an advancing Martian winter. Researchers had hoped that the lander would survive into the Martian winter so that it could witness polar ice developing at the spacecraft's exploration area. As much as three feet of solid carbon dioxide ice could appear in the area. Even if the lander had survived part way into the winter, it was very unlikely that it would have functioned throughout the entire winter due to the intense cold. The mission was chosen to be a fixed lander rather than a rover because:
1. costs were reduced through reuse of earlier equipment;
2. the area of Mars where Phoenix is landing is thought to be relatively uniform and thus traveling is of less value;
3. and the equipment weight that would be required to allow Phoenix to travel can instead be dedicated to more and better scientific instruments.
1. costs were reduced through reuse of earlier equipment;
2. the area of Mars where Phoenix is landing is thought to be relatively uniform and thus traveling is of less value;
3. and the equipment weight that would be required to allow Phoenix to travel can instead be dedicated to more and better scientific instruments.
Launch
Phoenix was launched on 4 August 2007, at 5:26:34 a.m. EDT (09:26:34 UTC) on a Delta 7925 launch vehicle from Pad 17-A of the Cape Canaveral Air Force Station. The launch was nominal with no significant anomalies. The Phoenix lander was placed on a trajectory of such precision that its first trajectory course correction burn, performed on August 10, 2007 at 7:30 a.m. EDT (11:30 UTC), was only 18 m/s.
The launch took place during a launch window extending from August 3, 2007 to August 24, 2007. Due to the small launch window the rescheduled launch of the Dawn mission (originally planned for July 7) had to stand down and was launched after Phoenix in September. The Delta 7925 was chosen due to its successful launch history, which includes launches of the Spirit and Opportunity Mars Exploration Rovers in 2003 and Mars Pathfinder in 1996.
A noctilucent cloud was created by the exhaust gas from the Delta II 7925 rocket used to launch Phoenix. The colors in the cloud formed from the prism-like effect of the ice particles present in the exhaust trail.
A noctilucent cloud was created by the exhaust gas from the Delta II 7925 rocket used to launch Phoenix. The colors in the cloud formed from the prism-like effect of the ice particles present in the exhaust trail.
Landing
The Jet Propulsion Laboratory made adjustments to the orbits of three satellites around Mars to be in the right place on May 25, 2008 to observe Phoenix as it entered the atmosphere and to monitor it up to one minute after landing. This information will allow for better design for future landers. The projected landing area was an ellipse 100 km by 20 km covering terrain which has been informally named "Green Valley" and contains the largest concentration of water ice outside of the poles.
Phoenix entered the Martian atmosphere at nearly 21,000 km (13,000 miles) per hour, and within 7 minutes had to be able to decrease its speed to 8 kilometres per hour (5.0 mph) before touching down on the surface. Confirmation of atmospheric entry was received at 4:46 p.m. PDT (23:46 UTC). Radio signals received at 4:53:44 p.m. PDT confirmed that Phoenix had survived its difficult descent and landed 15 minutes earlier, thus completing a 680 million km (422 million miles) flight from Earth.
MRO imaged Phoenix suspended from its parachute during descent through the Martian atmosphere.
Phoenix Landing Site near N. Polar cap
Communications from the surface
The robotic arm's first movement was delayed by one day when, on May 27, 2008, commands from Earth were not relayed to the Phoenix lander on Mars. The commands went to NASA's Mars Reconnaissance Orbiter as planned, but the orbiter's Electra UHF radio system for relaying commands to Phoenix temporarily shut off. Without new commands, the lander instead carried out a set of activity commands sent May 26 as a backup. On May 27 the Mars Reconnaissance Orbiter relayed images and other information from those activities back to Earth.
The robotic arm was a critical part of the Phoenix Mars mission. On May 28, scientists leading the mission, sent commands to unstow its robotic arm and take more images of its landing site. The images revealed that the spacecraft landed where it had access to digging down a polygon across the trough and digging into its the center.
The polygonal cracking in this area had previously been observed from orbit, and is similar to patterns seen in permafrost areas in polar and high altitude regions of Earth. A likely formation mechanism is that permafrost ice contracts when the temperature decreases, creating a polygonal pattern of cracks, which are then filled by loose soil falling in from above. When the temperature increases and the ice expands back to its former volume, it thus cannot assume its former shape, but is forced to buckle upwards. (On Earth, liquid water would probably enter at times along with soil, creating additional disruption due to ice wedging when the contents of the cracks freeze.)
The Lander's Robotic Arm touched soil on the red planet for the first time on May 31, 2008.
The robotic arm was a critical part of the Phoenix Mars mission. On May 28, scientists leading the mission, sent commands to unstow its robotic arm and take more images of its landing site. The images revealed that the spacecraft landed where it had access to digging down a polygon across the trough and digging into its the center.
The polygonal cracking in this area had previously been observed from orbit, and is similar to patterns seen in permafrost areas in polar and high altitude regions of Earth. A likely formation mechanism is that permafrost ice contracts when the temperature decreases, creating a polygonal pattern of cracks, which are then filled by loose soil falling in from above. When the temperature increases and the ice expands back to its former volume, it thus cannot assume its former shape, but is forced to buckle upwards. (On Earth, liquid water would probably enter at times along with soil, creating additional disruption due to ice wedging when the contents of the cracks freeze.)
The Lander's Robotic Arm touched soil on the red planet for the first time on May 31, 2008.
Approximate-color photomosaic of cryoturbation polygons due to the Martian permafrost.
Presence of shallow subsurface water ice
On June 19, 2008, NASA announced that dice-sized clumps of bright material in the "Dodo-Goldilocks" trench dug by the robotic arm had vaporized over the course of four days, strongly implying that they were composed of water ice which sublimated following exposure. While dry ice also sublimates, under the conditions present it would do so at a rate much faster than observed.
On July 31, 2008, NASA announced that Phoenix confirmed the presence of water ice on Mars, as predicted on 2002 by the Mars Odyssey orbiter. During the initial heating cycle of a new sample, TEGA's mass spectrometer detected water vapor when the sample temperature reached 0 °C. Liquid water cannot exist on the surface of Mars with its present low atmospheric pressure, except at the lowest elevations for short periods.
With Phoenix in good working order, NASA announced operational funding through September 30, 2008. The science team labored to determine whether the water ice ever thaws enough to be available for life processes and if carbon-containing chemicals and other raw materials for life are present.
On July 31, 2008, NASA announced that Phoenix confirmed the presence of water ice on Mars, as predicted on 2002 by the Mars Odyssey orbiter. During the initial heating cycle of a new sample, TEGA's mass spectrometer detected water vapor when the sample temperature reached 0 °C. Liquid water cannot exist on the surface of Mars with its present low atmospheric pressure, except at the lowest elevations for short periods.
With Phoenix in good working order, NASA announced operational funding through September 30, 2008. The science team labored to determine whether the water ice ever thaws enough to be available for life processes and if carbon-containing chemicals and other raw materials for life are present.
There is water ice on Mars within reach of the Mars Phoenix Lander, NASA scientists announced.
Photographic evidence settles the debate over the nature of the white material seen in photographs sent back by the craft. As seen in lower left of this image, chunks of the ice sublimed (changed directly from solid to gas) over the course of four days, after the lander's digging exposed them.
"It must be ice," said the Phoenix Lander's lead investigator, Peter Smith. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice."
The confirmation that water ice exists in the area directly surrounding the lander is big and good news for the Martian mission. NASA's stated goal for the Mars Phoenix was to find exactly this -- water ice -- and then analyze it. With the latest news, the first step is accomplished. All that's left now is to get the water into the Phoenix's instruments, a task which has occasionally proven more difficult than anticipated.
Photographic evidence settles the debate over the nature of the white material seen in photographs sent back by the craft. As seen in lower left of this image, chunks of the ice sublimed (changed directly from solid to gas) over the course of four days, after the lander's digging exposed them.
"It must be ice," said the Phoenix Lander's lead investigator, Peter Smith. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice."
The confirmation that water ice exists in the area directly surrounding the lander is big and good news for the Martian mission. NASA's stated goal for the Mars Phoenix was to find exactly this -- water ice -- and then analyze it. With the latest news, the first step is accomplished. All that's left now is to get the water into the Phoenix's instruments, a task which has occasionally proven more difficult than anticipated.
Wet Chemistry
On June 24, 2008, NASA's scientists launched a major series of tests. The robotic arm scooped up more soil and delivered it to 3 different on-board analyzers: an oven that baked it and tested the emitted gases, a microscopic imager, and a wet chemistry lab. The lander's Robotic Arm scoop was positioned over the Wet Chemistry Lab delivery funnel on Sol 29 (the 29th Martian day after landing, i.e. June 24, 2008). The soil was transferred to the instrument on Sol 30 (June 25, 2008), and Phoenix performed the first wet chemistry tests. On Sol 31 (June 26, 2008) Phoenix returned the wet chemistry test results with information on the salts in the soil, and its acidity. The wet chemistry lab was part of the suite of tools called the Microscopy, Electrochemistry and Conductivity Analyzer (MECA).
Preliminary wet chemistry lab results showed the surface soil is moderately alkaline, between pH 8 and 9. Magnesium, sodium, potassium and chloride ions were found; the overall level of salinity is modest. Chloride levels were low, and thus the bulk of the anions present were not initially identified. The pH and salinity level were viewed as benign from the standpoint of biology. TEGA analysis of its first soil sample indicated the presence of bound water and CO2 that were released during the final (highest-temperature, 1,000°C) heating cycle.
On August 1, 2008, Aviation Week reported that "The White House has been alerted by NASA about plans to make an announcement soon on major new Phoenix lander discoveries concerning the "potential for life" on Mars, scientists tell Aviation Week & Space Technology."[48] This led to a subdued media speculation on whether some evidence of past or present life had been discovered.To quell the speculation, NASA released preliminary and unconfirmed findings which suggest that Mars soil contains perchlorate and thus may not be as earth-like and life-friendly as thought earlier.
Preliminary wet chemistry lab results showed the surface soil is moderately alkaline, between pH 8 and 9. Magnesium, sodium, potassium and chloride ions were found; the overall level of salinity is modest. Chloride levels were low, and thus the bulk of the anions present were not initially identified. The pH and salinity level were viewed as benign from the standpoint of biology. TEGA analysis of its first soil sample indicated the presence of bound water and CO2 that were released during the final (highest-temperature, 1,000°C) heating cycle.
On August 1, 2008, Aviation Week reported that "The White House has been alerted by NASA about plans to make an announcement soon on major new Phoenix lander discoveries concerning the "potential for life" on Mars, scientists tell Aviation Week & Space Technology."[48] This led to a subdued media speculation on whether some evidence of past or present life had been discovered.To quell the speculation, NASA released preliminary and unconfirmed findings which suggest that Mars soil contains perchlorate and thus may not be as earth-like and life-friendly as thought earlier.
Robotic arm and camera
The Robotic Arm (RA) is designed to extend 2.35 m from its base on the lander, and has the ability to dig down to 0.5 m below the surface. It took samples of dirt and ice that were be analyzed by other instruments on the lander. The arm was designed and built for the Jet Propulsion Laboratory by Alliance Spacesystems, LLC (a subsidiary of MacDonald Dettwiler & Associates (MDA)) in Pasadena, California. Commands were sent for the arm to be deployed on May 28, 2008, beginning with the pushing aside of a protective covering intended to serve as a redundant precaution against potential contamination of Martian subsoil by Earthly lifeforms. The Robotic Arm Camera (RAC) attached to the Robotic Arm just above the scoop was able to take full-color pictures of the area, as well as verify the samples that the scoop returned, and examined the grains of the area where the Robotic Arm had just dug. The camera was made by the University of Arizona and Max Planck Institute for Solar System Research, Germany.
The Robotic Arm Camera (RAC). The box-shaped chassis of the camera measures 78 mm x 61 mm x 62 mm (LxWxH). The lighting assemblies (above and below the camera objective) include a total number of 26 red, 26 green and 52 blue Light Emitting Diodes (LED). Credit: LPL.
Robotic Arm (RA) with Robotic Arm Camera (RAC) and scoop. The 4-needle device that is located between scoop and RAC is the Thermal and Electrical Conductivity Probe (TECP). This probe is part of the MECA payload (although it is not included in the MECA box on the lander deck). Credit: JPL and MPS.
Thermal and evolved gas analyzer
NASA's Phoenix Mars Lander carries an instrument to heat and sniff samples of Martian soil and ice to analyze some ingredients.
The Thermal and Evolved-Gas Analyzer will study substances that are converted to gases by heating samples delivered to this instrument by the lander's robotic arm. It provides two types of information. One of its tools, called a differential scanning calorimeter (on the left in this photograph) monitors how much power is required to increase the temperature of the sample at a constant rate. This reveals
The Thermal and Evolved-Gas Analyzer will study substances that are converted to gases by heating samples delivered to this instrument by the lander's robotic arm. It provides two types of information. One of its tools, called a differential scanning calorimeter (on the left in this photograph) monitors how much power is required to increase the temperature of the sample at a constant rate. This reveals
Mars Descent Imager
MARDI was included among the collection of science instruments on Phoenix to provide information about the geographic context of landforms around the landing zone. However, pre-launch testing of the spacecraft identified a potential problem in handling data from the camera during the crucial moments of final descent. This led to a decision not to use the camera.
MARDI was designed and built to acquire a series of wide-angle, color images of the landing site during the final three minutes of the descent to the surface of Mars. These images would have supplemented images taken from orbit to help scientists understand whether the landing site is representative of the rest of Mars' northern plains. The camera incorporates an innovative electronics design to enable high-quality scientific data acquisition in a very compact package. It weighs about one pound, less than any previous camera sent to Mars, and is also extremely conservative of power, using only three watts during data acquisition. It has a refractive optics system that collects and bends light to enable a 66-degree-wide field of view. The instrument uses a charged-coupled device that produces high density, 1024 x 1024 pixel images, each with an exposure time of 4 milliseconds. The instrument also includes a small microphone that, like the camera, will not be used.
A potential problem with the spacecraft's data handling, not with the camera itself, led to the decision not to use the instrument. Tests of the assembled lander found that an interface card would have a small possibility of triggering loss of some vital engineering data if it were to receive imaging data during a critical phase of final descent. That possibility, though small, was judged to be an unacceptable risk, and the potential problem with the interface card was identified too late for changing hardware. The card has circuitry that routes data from various parts of the payload. An alternative plan, to take just one image with the descent camera and store it in the camera, was assessed. However, that would have required changes to timing of events during the spacecraft's descent, so that alternative was also rejected as still posing unacceptable risk.
MARDI was built by a team at Malin Space Science Systems led by Mike Malin. This team was responsible for designing the MARDI for the Mars Polar Lander and the Mars Surveyor 2001 Lander missions. When the 2001 lander mission was cancelled, MARDI was put into bonded storage at NASA's Jet Propulsion Laboratory until it gained a new berth in the payload of the Phoenix mission.
MARDI was built by a team at Malin Space Science Systems led by Mike Malin. This team was responsible for designing the MARDI for the Mars Polar Lander and the Mars Surveyor 2001 Lander missions. When the 2001 lander mission was cancelled, MARDI was put into bonded storage at NASA's Jet Propulsion Laboratory until it gained a new berth in the payload of the Phoenix mission.
Wet chemistry lab
This is an illustration of soil analysis on NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL will attempt to determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential.
The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.
The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.
Meteorological station
The Meteorological Station (MET) recorded the daily weather of Mars during the course of the Phoenix mission. It is equipped with a wind indicator and pressure and temperature sensors. The MET also contains a LIDAR (light detection and ranging) device for sampling the number of dust particles in the air.
The surface wind velocity, pressure and temperatures were also monitored over the mission (from the tell-tale, pressure and temperature sensors) and show the evolution of the atmosphere with time. To measure dust and ice contribution to the atmosphere, a LIDAR was employed. The LIDAR collected information about the time-dependent structure of the planetary boundary layer by investigating the vertical distribution of dust, ice, fog and clouds in the local atmosphere.
The LIDAR was operated for the first time at noon on Sol 3 (May 29, 2008), recording the first surface extraterrestrial atmospheric profile. This first profile indicated well mixed dust in the first few kilometers of the atmosphere of Mars, where the planetary boundary layer was observed by a marked decrease in scattering signal.
The surface wind velocity, pressure and temperatures were also monitored over the mission (from the tell-tale, pressure and temperature sensors) and show the evolution of the atmosphere with time. To measure dust and ice contribution to the atmosphere, a LIDAR was employed. The LIDAR collected information about the time-dependent structure of the planetary boundary layer by investigating the vertical distribution of dust, ice, fog and clouds in the local atmosphere.
The LIDAR was operated for the first time at noon on Sol 3 (May 29, 2008), recording the first surface extraterrestrial atmospheric profile. This first profile indicated well mixed dust in the first few kilometers of the atmosphere of Mars, where the planetary boundary layer was observed by a marked decrease in scattering signal.
Animation of TEGA Sample Delivery and Analysis
Animation of MARDI Instrument
Atomic Force Micro-scope Operation
Animation of Wet Chemistry Laboratory
Animation of Wet Chemistry Laboratory
Animation of TEGA Sample Delivery and Analysis
The 2003-2004 observations of methane gas on Mars were made remotely by three teams working with separate data. If the methane is truly present in the atmosphere of Mars, then something must be producing it on the planet now, because the gas is broken down by sunlight within 300 years, therefore the importance to search for biological potential or habitability of the Martian arctic's soils. Methane could also be the product of a geochemical process or the result of volcanic or hydrothermal activity. Other future missions may enable us to discover whether life does indeed exist on Mars today.
Parachute deployment was about 7 seconds later than expected, leading to a landing position some 25-28 km long (east), near the edge of the predicted 99% landing ellipse. The reason for this delay is not publicly known. Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera photographed Phoenix suspended from its parachute during its descent through the Martian atmosphere. This marks the first time ever one spacecraft has photographed another in the act of landing on a planet (the Moon not being a planet, but a satellite). The same camera also imaged Phoenix on the surface with enough resolution to distinguish the lander and its two solar cell arrays.
It scooped dirt and started sampling the Martian soil for ice after days of testing. Phoenix's Robotic Arm Camera took an image underneath the lander on sol 5 that shows patches of a smooth bright surface uncovered when thruster exhaust blew off overlying loose soil. It was later shown to be ice. Ray Arvidson of Washington University in St. Louis said: "We could very well be seeing rock, or we could be seeing exposed ice in the retrorocket blast zone."
which temperatures are transition points from solid to liquid and from liquid to gas for ingredients in the sample. The gases that are released, or "evolved" by this heating then go to a mass spectrometer (on the right), a tool that can identify the chemicals.