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Forum:Satellites - Robotic Probes
Topic:NASA's Mars Odyssey spacecraft orbiting Mars
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Odyssey's longevity enables continued science, including the monitoring of seasonal changes on Mars from year to year and the most detailed maps ever made of most of the planet. In 2002, the spacecraft detected hydrogen just below the surface throughout Mars' high-latitude regions. The deduction that the hydrogen is in frozen water prompted NASA's Phoenix Mars Lander mission, which confirmed the theory in 2008. Odyssey also carried the first experiment sent to Mars specifically to prepare for human missions, and found radiation levels around the planet from solar flares and cosmic rays are two to three times higher than around Earth.

Odyssey also has served as a communication relay, handling most of the data sent home by Phoenix and NASA's Mars Exploration Rovers Spirit and Opportunity. Odyssey became the middle link for continuous observation of Martian weather by NASA's Mars Global Surveyor and NASA's Mars Reconnaissance Orbiter (MRO).

Odyssey will support the 2012 landing of the Mars Science Laboratory (MSL) and surface operations of that mission. MSL will assess whether its landing area has had environmental conditions favorable for microbial life and preserving evidence about whether life has existed there. The rover will carry the largest, most advanced set of instruments for scientific studies ever sent to the Martian surface.

"The Mars program clearly demonstrates that world-class science coupled with sound and creative engineering equals success and longevity," said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington.

Other recent NASA spacecraft at Mars include the Mars Global Surveyor that began orbiting the Red Planet in 1997. The Spirit and Opportunity rovers landed on Mars in January 2004. They have been exploring for six years, far surpassing their original 90-day mission. Phoenix landed May 25, 2008, farther north than any previous spacecraft to the planet's surface. The mission's biggest surprise was the discovery of perchlorate, an oxidizing chemical on Earth that is food for some microbes, but potentially toxic for others. The solar-powered lander completed its three-month mission and kept working until sunlight waned two months later. MRO arrived at Mars in 2006 on a search for evidence that water persisted on the planet's surface for a long period of time.

Odyssey is managed by JPL for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft. JPL and Lockheed Martin collaborate on operating the spacecraft.

Robert Pearlman
Odyssey resumes work after 'B-side' switch

NASA's Mars Odyssey orbiter, already the longest-working spacecraft ever sent to Mars, has successfully switched to using its redundant computer, a system that has not been used since before its launch in 2001.

Odyssey relayed data to Earth late Sunday (Nov. 11, 2012) that it received from NASA's Opportunity rover on Mars using the orbiter's fresh "B-side" radio for UHF (ultra-high frequency) communications. In plans for this week are relays for the newest Mars rover, Curiosity, and resumption of Odyssey's own scientific observations.

"The side-swap has gone well. All the subsystems that we are using for the first time are performing as intended," said Odyssey Project Manager Gaylon McSmith of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Like many spacecraft, Odyssey carries a pair of redundant main computers, so that a backup is available if the other fails. Odyssey's "A-side" computer and "B-side" computer each have several other redundant subsystems linked to just that computer.

The Odyssey team decided to switch to the B-side computer to begin using its inertial measurement unit. This gyroscope-equipped device senses changes in the spacecraft's orientation, providing important information for control of pointing the antenna, solar arrays and instruments.

"We have been on the A side for more than 11 years. Everything on the A side still works, but the inertial measurement unit on that side has been showing signs of wearing out," said Odyssey Mission Manager Chris Potts at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We will swap to the B side on Nov. 5 so that we still have some life available in reserve on the A side."

In many potential problem situations, the Odyssey's autonomous fault-protection response would switch the spacecraft from the active side to the other side. By preserving the capability of switching back to a fully functional A side, the mission continues to have the available protection of switching sides temporarily and correcting any fixable anomaly on the B side.

"The spare inertial measurement unit is factory new, last operated on the day before launch," Potts said.

Odyssey launched April 7, 2001, began orbiting Mars on Oct. 24 of that year, began systematic science observations of Mars in early 2002, and broke the previous record for longest-working Mars probe in December 2010.

Odyssey's longevity enables continued science, including monitoring the seasonal changes on Mars from year to year, and continued relay service.

"It is testimony to the excellent design of this spacecraft and operation of this mission in partnership with Lockheed Martin that we have brand-new major components available to begin using after more than 11 years at Mars," McSmith said.

SpaceAholicNASA release
Veteran NASA Spacecraft Nears 60,000th Lap Around Mars, No Pit Stops

NASA's Mars Odyssey spacecraft will reach a major milestone June 23, when it completes its 60,000th orbit since arriving at the Red Planet in 2001.

Named after the bestselling novel "2001: A Space Odyssey" by Arthur C. Clarke, Odyssey began orbiting Mars almost 14 years ago, on Oct. 23, 2001. On Dec. 15, 2010, it became the longest-operating spacecraft ever sent to Mars, and continues to hold that record today.

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.

"This orbital milestone is an opportunity to celebrate Odyssey's many achievements," said Jim Green, NASA's director of Planetary Science. "Odyssey will continue to help lay a foundation for the first humans to Mars in the 2030s through NASA's Journey to Mars initiative."

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 "line" encircling Mars that 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.

"Upcoming observations will focus on what is happening in the Martian atmosphere in the morning, such as clouds, hazes and fogs, and on frosts on the surface that burn off by later in the day," said Jeffrey Plaut, Odyssey project scientist at JPL.

The planned drift to a morning-daylight orbit began in 2012, was accelerated in 2014, and will be completed with a maneuver in November to lock in the orbit timing so that each pass over the equator occurs at the same time of day.

"We have performed many orbit maneuvers over the long life of this mission, and we will use that experience conducting the one to halt the drift," said Steve Sanders, Odyssey spacecraft engineer at Lockheed Martin Space Systems in Denver.

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, Florida. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Odyssey Project for NASA's Science Mission Directorate in Washington. Lockheed Martin built the spacecraft and collaborates with JPL in mission operations. Arizona State University, Tempe, provided and operates THEMIS.

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