NEXT: ROVERS, SCOOPERS AND MAYBE EVEN ASTRONAUTS

By Jeffrey Kluger

Even before all the talk of Martian microfossils, the Red Planet was a hot target for NASA, with as many as 10 unmanned missions tentatively scheduled during the next 10 years. After the buzz created by last week's foot-high LIFE ON MARS! headlines, all those missions suddenly look a lot less tentative. And with President Clinton choosing this moment to pledge his continued support for space exploration, at least some people at NASA are beginning to whisper again about a project whose name they long dared not speak: a manned mission to Mars.

In general, trans-Martian travel is possible for only six to eight weeks every 25 months; it is then that Mars' and Earth's orbital pas de deux around the sun brings the two planets close enough to make the trip practical. The next window opens this fall, and NASA intends to take advantage of it. Between Nov. 6 and Dec. 31, the space agency will launch two missions to Mars. The first, the Mars Global Surveyor, is an orbiter that will arrive in September 1997 and spend at least four months circling the planet and mapping its geology and climate. Despite its small size (10 ft. tall; 2,300 lbs.), the spacecraft carries quite an instrument load, including magnetometers to measure magnetic fields, a laser altimeter that can gauge the height of surface features to within 30 ft., and optical cameras that can detect objects as small as a car.

A month or so after Global Surveyor is launched, a sister ship, the Mars Pathfinder, will follow it into space. Like NASA's unmanned Viking ships of the 1970s, Pathfinder will land on Mars' pockmarked surface. Unlike the Vikings, Pathfinder will have someplace to go once it gets there. After the pyramid-shaped payload touches down, its sides will open like the petals of a 3-ft.-tall flower to reveal a six-wheeled rover. Powered by solar cells and D-cell batteries, the 2-ft.-long robot vehicle is supposed to hum away from the landing pod, crawling at 2 ft. a minute, and sample the soil for several weeks--or until its batteries die.

If all goes well with these flights, as many as four more pairs will follow at two-year intervals beginning in December 1998. Though the second lander will not be as mobile as Pathfinder, it will have an improved stereoscopic camera and a robotic shovel, allowing it to scoop up soil and conduct more detailed studies of its chemical composition. Unfortunately, none of these ships is designed to test for what captured the world's imagination last week: Martian life.

"Sure, if we got lucky, dug into the soil and came up with a little plant, we could detect that," says Norm Haynes, director of the Mars Exploration Program at the Jet Propulsion Laboratory in Pasadena, California. "But there's nothing we can send from Earth that can even begin to duplicate what the people who studied the Martian meteorite did in the lab."

To conduct experiments that subtle, it may be necessary not just to send a spacecraft to Mars but to bring a bit of Mars back to Earth. "It's always been clear that we're aiming for a sample-return mission," says Haynes. "A recent study projects one around 2005, but with more money we could probably do it sooner."

Whether more money will be forthcoming is an open question. NASA Administrator Daniel Goldin was careful not to ask for any handouts--a touchy subject this election year--but he was also careful to arrange for saturation coverage of last week's findings. In the wake of such news, he believes, "a sample- return mission becomes more tantalizing than ever."

As for the possibility of one day sending astronauts instead of robots to obtain the rocks? "What happened certainly doesn't hurt that idea," Haynes concedes.

--By Jeffrey Kluger