Mission Type: Lander
Launch Vehicle: Delta II 7925
Launch Site: Cape Canaveral
NASA Center: Jet Propulsion Laboratory
1) Robotic Arm (RA)
2) Microscopy, Electrochemistry, and Conductivity Analyzer (MECA)
3) Robotic Arm Camera (RAC)
4) Surface Stereo Imager (SSI)
5) Thermal and Evolved Gas Analyzer (TEGA)
6) Mars Descent Imager (MARDI)
7) Meteorological Station (MET)
Project Manager: Dr. Barry G. Goldstein
Principal Investigator: Dr. Peter H. Smith
NSSDC Master Catalog: Phoenix Mars Lander, http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=2007-034A
Phoenix Mars Mission, http://phoenix.lpl.arizona.edu
NASA Data Shed New Light About Water and Volcanoes on Mars, http://www.nasa.gov/mission_pages/phoenix/news/phx20100909.html
NASA Phoenix Results Point to Martian Climate Cycles, http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20090702.html
Favorable opportunities to launch missions to Mars come about every 26 months, but the 2007 launch opportunity was the best in several years for sending a surface mission to the northern region on Mars. The Phoenix mission took advantage of this opportunity and launched a lander with a robotic arm to Mars on 4 August 2007 on board a three-stage Delta II launch vehicle.
NASA's Mars Odyssey orbiter found evidence in early 2002 that the northern region on Mars shelters high concentrations of water ice mixed with the soil just beneath the surface. Phoenix was sent with a payload of science instruments particularly appropriate for examining an environment of ice and soil. Phoenix's robotic arm was designed to dig trenches, scoop up soil and water ice samples, and deliver these samples to the Thermal and Evolved Gas Analyzer (TEGA) and the Microscopy, Electrochemistry and Conductivity Analyzer (MECA) instruments for detailed chemical and geological analysis.
Data from Phoenix suggest liquid water has interacted with the Martian surface throughout the planet's history and into modern times. The research also provides new evidence that volcanic activity has persisted on the Red Planet into geologically recent times, several million years ago.
Phoenix precisely measured isotopes of carbon and oxygen in the carbon dioxide of the Martian atmosphere. Isotopes are variants of the same element with different atomic weights. "Isotopes can be used as a chemical signature that can tell us where something came from, and what kinds of events it has experienced," said Paul Niles, a space scientist at NASA's Johnson Space Center in Houston. This chemical signature suggests that liquid water primarily existed at temperatures near freezing and that hydrothermal systems similar to Yellowstone's hot springs have been rare throughout the planet's past. Measurements concerning carbon dioxide showed Mars is a much more active planet than previously thought. The results imply Mars has replenished its atmospheric carbon dioxide relatively recently through volcanic emissions, and the carbon dioxide has reacted with liquid water present on the surface.
The mission's biggest surprise was finding a multi-talented chemical named perchlorate in the Martian soil. "With perchlorate, for example, we see links to atmospheric humidity, soil moisture, a possible energy source for microbes, even a possible resource for humans" said Michael Hecht of NASA's Jet Propulsion Laboratory, Pasadena, Calif. 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. Perchlorate 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.
Another surprise from Phoenix was finding ice clouds and precipitation more Earth-like than anticipated. The lander's Canadian laser instrument used for studying the atmosphere detected snow falling from clouds.
Phoenix's cameras also returned more than 25,000 pictures from sweeping vistas to near the atomic level using the first atomic force microscope ever used outside Earth.
"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.
Phoenix ended communications in November 2008 as the approach of Martian winter depleted energy from the lander's solar panels.