Martian Satellites Greet Each Other

MGS
This view is an enlargement of an image of NASA’s Mars Odyssey spacecraft taken by the Mars Orbiter Camera aboard NASA’s Mars Global Surveyor while the two spacecraft were about 90 kilometers (56 miles) apart.
Credit: JPL/MSSS

New photographs from NASA’s Mars Global Surveyor spacecraft are the first pictures ever taken of a spacecraft orbiting a foreign planet by another spacecraft orbiting that planet.

The new images of the European Space Agency’s Mars Express and NASA’s Mars Odyssey are available on the Internet from NASA and from Malin Space Science Systems, the San Diego company that built and operates the camera.

Mars Global Surveyor has been orbiting Mars since 1997, Mars Odyssey since 2001. Both are managed for NASA by the Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif. Mars Express has been in orbit since late 2003.

Mars Express was passing about 155 miles away when the Mars Orbiter Camera on Mars Global Surveyor photographed it on April 20. The next day, the camera caught Mars Odyssey passing 56 to 84 miles away.

All three spacecraft are moving at almost 7,000 miles per hour, and at 62 miles distance the field-of-view of the Mars Orbiter Camera is only 830 yards across. If timing had been off by only a few seconds, the images would have been blank.

About 85 percent of images and other data from NASA’s twin Mars rovers, Spirit and Opportunity, have reached Earth via communications relay by Odyssey, which receives transmissions from both rovers every day. The Odyssey mission was extended in August 2004.

An artist's rendition of 2001 Mars Odyssey as it enters orbit
An artist’s rendition of 2001 Mars Odyssey as it entered orbit. On Oct. 28, 2003, during a period of intense solar activity, the radiation-detecting instrument stopped working properly.
Credit: JPL

JPL’s Dr. Jeff Plaut, project scientist for Odyssey, said "One goal is to look for climate change. During the prime mission we tracked dramatic seasonal changes, such as the comings and goings of polar ice, clouds and dust storms. Now, we have begun watching for year-to-year differences at the same time of year." Plans call for Odyssey to aid NASA’s Mars Reconnaissance Orbiter, due to reach Mars in March 2006, by monitoring atmospheric conditions during months when the newly arrived orbiter uses calculated dips into the atmosphere to alter its orbit into the desired shape.

Odyssey was launched April 7, 2001, and used the same "aerobraking" technique to shape its orbit during the initial months after it reached Mars on October 23, 2001. The spacecraft carries three research systems: a camera system made up of infrared and visible-light sensors; a spectrometer suite with a gamma ray spectrometer, a neutron spectrometer and a high-energy neutron detector; and a radiation environment detector.

Less than a month after the science mapping campaign began, the team announced a major discovery. The gamma ray and neutron instruments detected copious hydrogen just under Mars’ surface in the planet’s south polar region. Researchers interpret the hydrogen as frozen water — enough within about a meter (3 feet) of the surface, if the ice were melted, to fill Lake Michigan a couple times.

Mars 2001 Odyssey
Hydraotes Chaos (Released 18 August 2004)
Image Credit: NASA/JPL/Arizona State University

A few of Odyssey’s other important accomplishments so far include:

– As summer came to northern Mars and the north polar covering of frozen carbon dioxide shrank, Odyssey found abundant frozen water in the north, too.

– Infrared mapping shows that a mineral called olivine is widespread. This indicates the environment has been quite dry, because water exposure alters olivine into other minerals.

– Findings indicate the amount of frozen water in some relatively warm regions on Mars is too great to be in equilibrium with the atmosphere, suggesting that Mars may be going through a period of climate change. Features visible near small, young gullies in some Odyssey images may be slowly melting snowpacks left over from a martian ice age.

– The first experiment sent to Mars specifically in preparation for human missions found that radiation levels around Mars, from solar flares and cosmic rays, are two to three times higher than around Earth.

– Odyssey’s camera system has obtained the most detailed complete global maps of Mars ever, with daytime and nighttime infrared images at a resolution of 100 meters (328 feet).


Related Web Pages

Giving Mars Back its Heartbeat
Looking for Martian Life
Should We Terraform?
Walking Naked on the Red Planet
United Nations of Mars
Living on Mars
The Martian Future
Mars Exploration Rover Mission: Home
Searching for water with MARSIS
MARSIS instrument design
You Are Here
Viking Biology Experiments
Life Beneath the Surface