NASA going back to mars

A year and a half after twin robot rovers thrilled space fans, 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, reports the AP.

According to Tucson Citizen Scientists also hope to get images of the two rovers, Opportunity and Spirit, that landed on Mars 20 months ago, he said. "We will be able to spot them and see their tracks if they have not been erased by the wind.

"It's really exciting that they may be alive and well, and so we can take images of the area and help influence what target to investigate," McEwen said of the robotic explorers.

There are expected to be attempts to photograph the wreckage of the Polar Lander and Beagle 2, which crashed on Mars.

The instruments are expected to give a detailed examination of a large portion of Mars for four years after arriving, he said. "We should have plenty of fuel to maintain it in orbit for a lot longer than the four years that's needed to complete the mission's goals." By then, the mission is expected to have collected 10 times the data of all other Mars missions combined, he said. The first milestone after the launch atop an Atlas 5 rocket will be to make images of the moon on Sept. 8.

"That won't be a spectacular image," he said. "We actually will be pretty far away by then, but this will be our first image of a target in-flight for testing the camera and for calibration purposes."