Observations from NASA's 2001 Mars Odyssey produced this high-energy neutron detector map of martian neutrons in the southern hemisphere. The blue region around the south pole indicates a high content of hydrogen in the upper 2 to 3 meters (7 to 10 feet) of the surface.

The neutrons were measured by the medium detector (in counts per second) during the first week of mapping, in February 2002. The space background neutrons have been subtracted. The pixels are 10 by 10 degrees.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The high-energy neutron detector was supplied by the Russian Aviation and Space Agency and is one of the instruments in the gamma ray spectrometer instrument suite, which was supplied by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. See http://grs.lpl.arizona.edu for more information. Odyssey mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.