GRS

Mars Odyssey

Gamma Ray Spectrometer

The Gamma Ray Spectrometer (GRS) is a suite of three instruments. It has a Gamma Subsystem, Neutron Spectrometer and High Energy Neutron Detector. Principal Investigator Dr. William Boynton says that he sort of feels like he has been in his own odyssey for the last 16 years waiting to get a new chance to send the Gamma Ray Spectrometer to Mars. The first GRS was lost when the Mars Observer failed to obtain orbit in 1993.

Scientists did not expect to have such strong signals from Mars at this point and Bill says they were "blown away" by the data. Some of the signals from Mars are very strong and according to Bill Boynton, the signal that they have been receiving loud and clear is that there is a lot of ice on Mars. Ice is detected by emissions from the element hydrogen.

This first picture is a global view of what Mars would look like if you could see it in neutrons. It comes from the Neutron Spectrometer provided by Los Alamos National Laboratory.

Global spectrometer image

The following represents the same data as viewed from the south pole.

South Pole

This image is also from the south pole but it comes from the HEND (High Energy Neutron Detector) instrument provided by the Russian Aviation and Space Agency.

High-energy image of South Pole

In all three images, it seems clear that there is an abundance of ice. After only a week of looking at the data, the scientists are quite comfortable releasing this information. The three different instruments use two different techniques, but lead the scientists to the same conclusion. There is a lot of hydrogen and a lot of ice in the southern hemisphere of Mars. When the boom is extended and the Gamma Ray Spectrometer is moved away from the body of the spacecraft, it will be able to detect the presence of approximately 20 different elements (including silicon, oxygen, iron, magnesium, potassium, aluminum, calcium, sulfur, and carbon).

The scientists are very excited about what they have seen so far, but they are also very excited about what they hope to find. It will take time, but they plan to map the surface of Mars for many different elements.

For more information about the Gamma Ray Spectrometer, go to: http://grs.lpl.arizona.edu/

- 1 March 2002

Last Updated:
8 January 2015