NASA’s Mars Odyssey spacecraft reached a major milestone June 23, when it completed its 60,000th orbit since arriving at the Red Planet in 2001.
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| Source: NASA |
Odyssey, which discovered widespread water ice just beneath the surface of the Red Planet, is still going strong today, serving as a key communications relay for NASA’s Mars rovers and making continued contributions to planetary science.
Odyssey’s orbital milestone translates into about 888 million miles (1.43 billion kilometers) traversed by the spacecraft. In addition to the 286 million miles (460 million kilometers) covered on its trip from Earth to Mars, the spacecraft is a high-mileage vehicle like no other, but remains in fine condition.
“The spacecraft is in good health, with all subsystems functional and with enough propellant for about 10 more years,” said David Lehman, project manager for the Mars Odyssey at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.
Odyssey’s major discoveries began in the early months of its two-year primary mission, with gamma-ray and neutron measurements that indicated plentiful water ice just beneath the surface at high latitudes on Mars. The spacecraft’s unexpectedly long service has enabled achievements such as completion of the highest-resolution global map of Mars and observation of seasonal and year-to-year changes, such as freezing and thawing of carbon dioxide.
Through its many accomplishments, the spacecraft also has aided NASA’s preparations for human missions to Mars by monitoring radiation in the environment around the planet via the Mars Radiation Environment Experiment, developed at NASA’s Johnson Space Center in Houston.
Odyssey currently is completing an adjustment to an orbit that will position it to pass over Martian terrain lit by early-morning sunlight rather than afternoon light. In its current orbit, the spacecraft always flies near each pole and along what is called the terminator. The terminator is a moving “line” that encircles Mars and passes through any point on the planet’s surface at sunrise and again at sunset, separating the portion of Mars lit by the sun from the portion experiencing darkness, dividing day and night. The position of this line varies by time of day and time of year.
To date, Odyssey’s Thermal Emission Imaging System (THEMIS) has yielded 208,240 images in visible-light wavelengths and 188,760 in thermal infrared wavelengths. THEMIS images are the basis for detailed global maps and identification of some surface materials, such as chloride salt deposits and silica-rich terrain. The infrared imaging also indicates how quickly regions of the surface cool at night or warm in sunlight, telling researchers how dusty or rocky the ground is.
Odyssey’s three-instrument Gamma Ray Spectrometer (GRS) suite detected significant amount of hydrogen on the planet – interpreted as water ice hidden beneath the surface. This discovery prompted NASA to send its Phoenix Mars Lander to an arctic plain on Mars in 2008, where it examined the water ice detected by Odyssey. The spectrometer suite also mapped global distribution of key chemical elements, such as iron and potassium. The University of Arizona, Tucson, headed its development. Two GRS instruments are still active: the high-energy neutron detector from the Russian Space Research Institute and the neutron spectrometer from Los Alamos National Laboratories in New Mexico.
As a communications relay for NASA’s Mars rovers, Odyssey has transmitted to Earth more than 90 percent of the data received from the Opportunity rover. Future plans for Odyssey include relay duty for NASA and European Space Agency landers arriving on Mars in 2016.
Odyssey launched on April 7, 2001 from Cape Canaveral Air Force Station.
