Mars Express, other probes to expand search for water

Europe's Beagle 2 lander will sniff for gases and hunt for fossils that could reveal evidence of present or past life on Mars.

June 26, 2000
Web posted at: 4:56 PM EDT (2056 GMT)

In this story: 'Southern hemisphere a bit tricky' A boost for slumping NASA Japan's Nozomi en route to Mars 'Friendly competition' among nations RELATED STORIES, SITES

By Richard Stenger
CNN.com Writer

(CNN) -- Within the next three years, several nations will attempt to dig deeper into the mystery of liquid water on Mars with an array of spacecraft, including a European probe that could land near a theoretical wet spot on the red planet.

larger   Mars Global Surveyor

larger   Mars Express

larger   2001 orbiter

larger   Nozomi orbiter

Mars currently hosts only one active spacecraft, NASA's Mars Global Surveyor, which took pictures that scientists say provide compelling evidence that water lurks near the surface.

At least three spacecraft slated to visit the martian system over the next few years could widen the search for water, an ingredient considered necessary for life.

Only the European Space Agency has firm plans to land a spacecraft on the red planet. The Beagle 2 will hitch a ride aboard the Mars Express orbiter, due to arrive in the Mars system in December 2003.

ESA is reviewing landing targets for the Beagle 2 lander, which will sniff the surface and atmosphere for signs of past or present life.

Given that all known life requires liquid water, the chance of searching near a wet spot on Mars intrigues Beagle 2 scientist Colin Pillinger. But landing near such a location would prove daunting.

"The southern hemisphere, where most of these (possible water sources) seem to be, is a bit tricky for Beagle 2. It will be going into autumn and winter in the southern hemisphere when Beagle arrives," he said.

The Beagle 2 would require more batteries to survive the deep cold, and the landing system cannot spare the additional weight.

Pillinger held out hope that the Beagle 2 could descend near one of the rare wet spots found in the northern hemisphere relatively close the equator.

But with a landing window 62 by 31 miles (100 km by 50 km), could the Beagle 2 hit one of those targets?

"That's a whole new ballgame. To pinpoint land you would need a communication system around Mars, so you can target it. But we could at least target for the general vicinity. That would be a smart move," he said.

From orbit, the Mars Express satellite will look for signs of water below and above the surface using ground-penetrating radar, infrared and other instruments.

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"The latest evidence that liquid water has flowed on Mars very recently makes Mars Express even more relevant," said Agustin Chicarro, a project scientist with the European Space Agency.

Global Surveyor scientists have calculated martian groundwater might lie at a depth of 100 meters to 1 km (109 yards to 0.6 mile).

"This means that the radar on board Mars Express should be able to detect it quite easily," said ESA project scientist Jean-Loup Bertaux.

The loss of two Mars probes in 1999 compelled NASA to revamp its Mars office. The new discovery could give the slumping program a needed lift.

"It has obviously precipitated a lot of interesting thinking in our science community," said Jim Garvin, a NASA staff scientist involved in the selection process for future Mars missions.

The Global Surveyor, which has taken more than 20,000 pictures since it began circling Mars in 1997, could extend its mission at least a year beyond its scheduled retirement in February, said orbiter scientist Michael Malin, who announced the discovery.

NASA will likely decide this summer whether to send an orbiter or a roving lander, or neither, to Mars in 2003.

"There is no chance (the water discovery) will change any of the instruments on those spacecraft," said NASA spokesman Don Savage. The planning phases for the missions are too far along.

However "there are ways that we can use the suites of instruments on them to look at those sites," he said.

The 2001 orbiter will use an infrared imager to look for water-related minerals around seepage sites identified by Surveyor.

A lander in 2003 could perhaps send a rover closer to a wet spot, although scientists caution that most of the sites seem dangerous, along steep gully walls and crater rims.

The proposed 2003 orbiter could magnify the visual search, snapping pictures with a resolution two or three times better than Surveyor, which already can distinguish objects as small as a sport-utility vehicle.

The prospect of liquid water near the surface of Mars gives new impetus to a multinational fleet of robot ships headed to the red planet.

Only one spacecraft is in transit to Mars now, a Japanese robot ship that will rendezvous with the red planet in 2003. The Nozomi orbiter was to reach Mars orbit in 1999 but sputtered during a slingshot maneuver around Earth.

Nozomi, also known as Planet-B, guzzled so much fuel during a course correction that it must wait four additional years. It will focus its instruments on the upper atmosphere, a study that could shed light on how Mars lost water over time.

Scientists have long thought Mars' surface coursed with water billions of years ago, based on evidence of liquid erosion and signs of ancient channels and seas. But the water all but disappeared as the planet cooled and its atmosphere thinned.

Water exists today as ice in the northern polar cap and as vapor in faint clouds. But until last week's announcement, few scientists held out hope that the cold, arid planet could possibly have retained liquid water into the recent geologic past.

Given that European and Japanese spacecraft should reach the martian system in 2003, the United States might feel pressured to join the exploration party, one NASA scientist acknowledged.

"I'm sure the U.S. would like to have a presence there," said Richard Zurek. A researcher at NASA's Jet Propulsion Laboratory, he is working on the proposed 2003 orbiter.

But scientists dismiss suggestions of a serious rivalry among government space agencies. "The instruments that are arriving (in 2003) have influenced our selections. We're trying to complement, not duplicate them," Zurek said.

Pillinger agreed. He acknowledged a "friendly competition," but added, "We are good at sharing our resources."

The world community should have plenty of time to cooperate on the search for martian water. No one will know exactly what the theoretical wet spots hold until probes study them directly, scientists said.

Such a search will require major advances in technology. Mars landing windows are currently measured in kilometers. A precise landing to search a nearby source for water would require a far more precise target touchdown area, one measured in meters.

Such a pinpoint landing will not happen until 2005 or 2008 at the earliest, said NASA deputy administrator Ed Weiler.

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Mars Global Surveyor
European Space Agency
Beagle 2

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