A year and a half after twin robot rovers thrilled space fans with their hijinks on Mars, NASA is heading there again.
A fourth Mars orbiter is set to blast off Wednesday, carrying some of the most sophisticated science instruments ever sent into space. Circling the Red Planet, the Mars Reconnaissance Orbiter will scan the desolate surface in search of sites to land more robotic explorers in the next decade.
“It’s time we start peeling back the onion layer and start looking at Mars from different vantage points,” said project manager James Graf of the Jet Propulsion Laboratory in Pasadena.
Like the three current spacecraft flying around Mars – including a European orbiter – the latest probe will seek evidence of water and other signs that the planet could have hosted life. The $720 million mission, which launches from Cape Canaveral, Fla., will also serve as a communications link to relay data to Earth.
Its powerful camera can snap the sharpest pictures yet of the planet’s rust-colored surface, with six times higher resolution than past images.
NASA took its first close-up pictures of Mars in 1965 when the Mariner 4 spacecraft zipped past the planet and snapped fewer than two dozen photos.
Since then, numerous probes that have landed, orbited or passed the planet have shot tens of thousands more images. But only about 2 percent of the planet has been viewed at high resolution.
“There are many unanswered questions about Mars,” project scientist Richard Zurek said.
The two-ton reconnaissance orbiter will be NASA’s last Mars orbiter this decade. Belt-tightening forced the space agency to cancel a $500 million mission planned for 2009.
However, two more landing attempts are set during the next four years. Scientists hope to use the orbiter’s detailed mapping to scout safe landing sites for the Phoenix Mars and Mars Science Laboratory missions slated for 2007 and 2009, respectively.
The information gleaned by the spacecraft could also help scientists decide where to send a lander during the next decade to return the first samples of Martian rocks and soil to Earth.
The stationary Phoenix lander will use a long robotic arm to explore the icy plains of the planet’s north pole. Later, the mobile Mars Science Laboratory will analyze rocks and soil in finer detail than the rovers Spirit and Opportunity, which have uncovered geologic evidence of past water activity since parachuting to opposite ends of Mars last year.
The solar-powered rovers are still trekking across the Martian surface, even though scientists had not expected the six-wheeled machines to last more than three months in the hostile Martian environment.
The reconnaissance orbiter will also try to find two ill-fated spacecraft – NASA’s Mars Polar Lander and Britain’s Beagle 2 lander – which lost contact during separate landing attempts. Earlier this year, the company that operates a camera aboard one of the current Mars orbiting spacecraft – the Global Surveyor – found what appeared to be the wreckage of Polar Lander based on grainy black-and-white images.
The Mars Reconnaissance Orbiter will launch aboard a Lockheed Martin Atlas V rocket for its two-year mission. It will adjust its flight path until it reaches Mars’ orbit in mid-March next year. Then it will use the friction of the atmosphere to lower itself to about 190 miles above the surface.
Along with its telescopic camera, the orbiter’s payload includes ground-penetrating radar that can probe up to a third of a mile beneath surface rock and ice for evidence of water. Other instruments can track daily weather changes and identify minerals.
Today, Mars is cold and dry with large caps of frozen water at its poles. But scientists think the planet was a wetter and possibly warmer place eons ago – conditions that might be conducive to life.
After the imaging phase, the orbiter will switch to its other role as a communication relay for Mars lander missions. It will be equipped with a powerful high-gain antenna that can transmit 10 times more data per minute than the current trio of satellites that includes NASA’s Global Surveyor and Mars Odyssey and the European Space Agency’s Mars Express.
“We will have a fire hose of data coming back instead of bringing it back through a little garden hose,” Graf said.
The spacecraft’s primary mission ends in 2010, but scientists say it has enough fuel to last until 2014.
Past Mars Missions
A look at NASA’s many Mars missions over the past four decades, listed by launch date:
— November 1964, Mariner 3: Spacecraft loses contact after takeoff. Mariner 4 launches three weeks later and in July 1965 becomes the world’s first spacecraft to take close-up pictures of Mars, returning 21 photos.
— February 1969, Mariner 6: Spacecraft flies past Mars in July 1969 and returns 75 photos.
— March 1969, Mariner 7: Spacecraft flies past Mars in August 1969 and returns 126 photos.
— May 1971, Mariner 8: Orbiter fails on launch. Mariner 9 orbiter arrives at Mars in November and operates until October 1972.
— August 1975, Viking 1: orbiter arrives at Mars in June 1976 followed by Viking 1 lander the next month. Orbiter operates until 1980; lander lasts until 1982.
— September 1975, Viking 2: Orbiter arrives at Mars in August 1976, and Viking 2 lander touches down the following month. Lander lasts until 1980; orbiter operates until 1987.
— September 1992, Mars Observer: Craft loses communication in August 1993 just before going into orbit around Mars.
— November 1996, Mars Global Surveyor: Orbiter reaches Mars in September 1997. Continues to operate.
— December 1996, Mars Pathfinder: Lander and Sojourner rover land on Mars in July 1997. Last transmission September 1997.
— December 1998, Mars Climate Orbiter: Lost on arrival in September 1999.
— January 1999 Mars Polar Lander: Spacecraft and accompanying Deep Space 2 microprobes lose contact during arrival at south pole of Mars in December 1999.
— March 2001, Mars Odyssey: Spacecraft reaches orbit October 2001. Continues to operate.
— June 2003, Mars rover Spirit: Craft sets down in the Gusev Crater region in January 2004. It has been examining rocks that suggest a wet and violent history in Mars’ early life. Continues to operate.
— July 2003, Mars rover Opportunity: Craft parachutes to Meridiani plains three weeks after Spirit’s touchdown. It has also found geological evidence of past water activity. Continues to operate.
— Aug. 10, 2005, Mars Reconnaissance Orbiter: Craft expected to enter orbit in March 2006.
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