NEXT STOP: MARS

By Jeffrey Kluger

Time was, Mars was a busy place. Everybody, it seemed--or at least everybody at NASA--wanted to fling something the Red Planet's way. First there were Mariner probes whizzing through the Martian neighborhood, then Mariner probes orbiting the planet. Next there was a Viking probe that actually landed on the surface, and another followed a few months later. Before long, so the thinking went, the unmanned probes would have surveyed the whole planet, and the manned missions could at last begin.

But before long never came. As the nation's interest in space travel waned in the post-Apollo years, Washington's willingness to bankroll every grand scheme the space agency came up with vanished. By the late 1970s, NASA--once the trust-fund baby of a doting Congress--had to be choosy about where it spent its money; for the most part, it didn't choose Mars.

Now, however, just as public interest has been rekindled by the first hints that there might have been life on Mars, ships from the U.S. and Russia are starting to fly again. On Nov. 6, NASA is scheduled to launch an unmanned craft that should be orbiting Mars by this time next year. Ten days later, Russia will fire off a second one, and two weeks after that, NASA will loft a third. If all goes well, NASA hopes to loose a flock more during the next 10 years. "After a hiatus of 20 years," says NASA Administrator Daniel Goldin, "America returns to Mars."

Ironically, much of the trans-Mars traffic comes from a change not so much in science as in economics: the new craft are cheap--dirt cheap, by space standards. Engineers at last appear to have learned how to build a spaceship on a budget, and as the costs come down, the ships are going back up. The attitude among space engineers has always been that bigger spacecraft are better, and much bigger ones are better still. But bigger is much more expensive. In 1992 Goldin was recruited from private industry in the hope that he would bring a hardheaded bookkeeper's approach to the hardware-driven NASA. Goldin accepted the challenge, vowing to build an agency that did things "faster, better, cheaper." Immediately he turned his attention to unmanned space probes.

Designed to survive on its own millions of miles from home, a probe only 6 ft. long can cost $1 billion--more than half the sticker price of a space shuttle. The problem is that even expensive ships can go south on you, which is just what happened in 1993, when the Mars Observer--a spacecraft that was NASA's only attempted Mars mission since 1976--apparently blew an aneurysm in a fuel line and spiraled off into space. Goldin decided that such Cadillac probes should be replaced with more-modest ones: stripped-down ships made of components already on the shelf. When skeptical NASA engineers began assembling these workbench spacecraft, they found them surprisingly elegant.

The Mars Global Surveyor, which NASA will launch this week, is one of these new spacecraft. Tipping the scale at 2,337 lbs., it is less than half the weight of the 5,672-lb. Observer. Just as important, it cost only $135 million--milk money next to the Observer's near billion-dollar price tag.

But small size and low price notwithstanding, Surveyor can do a lot. In September 1997, 10 months after launch, it will reach Mars, and must then slow down so it can drop into orbit. Too small to carry enough fuel for that braking maneuver, it will rely in part on aerobraking--dragging itself through Mars' upper atmosphere to let air friction help decelerate the craft.

Once in orbit, Surveyor will train a battery of instruments on the surface, among them a trio of cameras able to distinguish features as small as 10 ft. across. Geologists studying Surveyor's pictures will look largely for evidence of the planet's watery past--dried remains of beaches, scarring from glaciers. Where there's water, they know, there could be signs of long-ago life. "The high-resolution images are going to open up a whole new world," says geologist Bruce Jakosky of the University of Colorado. The Surveyor will carry a thermal detector that can analyze the makeup of rocks, a laser altimeter that can measure surface elevations, and an oscillator that can detect changes in spacecraft speed (which would suggest higher-gravity mass concentrations beneath the surface).

Surveyor should continue operating for two Earth years, but when it winks out, it won't be all alone. On Dec. 2, NASA plans to launch the $175 million Mars Pathfinder, which will not just orbit the planet but land on it. Though Pathfinder will leave Earth close to a month after Surveyor, its more direct trajectory will get it where it's going two months earlier--on July 4, 1997. After the 3-ft.-tall craft lands, its hinged sides will open to release the world's first planetary rover.

Resembling nothing so much as a six-wheeled milk crate, the rover has talents that belie its looks. Powered by both solar panels and batteries, it will drive about the vicinity of the landing site, using an X-ray spectrometer to sample the chemical makeup of rocks and the surrounding soil. No sensors will be aboard that can detect microfossils because this mission, like the others, was planned well before last summer's discovery of possible traces of ancient microbial life in a meteorite from Mars and last week's report of a similar find on a second piece of space rubble. That's probably just as well, since the rock and soil studies alone will be extremely slow going. The rover crawls along at less than 2 ft. per min., and must wait for periodic O.K.s from Earth and the lander before moving an inch. "This is a remarkably dumb machine," says project scientist Matthew Golombek. "It cannot roll and chew gum at the same time."

Between the launch of the two American ships, the Russians will set off for some Martian prospecting of their own. On Nov. 16, they will launch a combination Mars orbiter and lander dubbed Mars '96 that will reach the planet next September. The orbiter is designed to study atmospherics, magnetics and geology. The lander unit is actually made up of four landers; all will study seismology and geology, but two will act more as penetrators, allowing them to study rocks at a depth of 20 ft. Data that Mars '96 collects will be relayed home via Surveyor, which will be orbiting overhead. The mission once included a rover, but the Russians too had to learn the benefits of downsizing. "I have to worry about how to pay salaries next month," sighs Albert Galeyev of Russia's Institute of Space Research.

For the moment, it appears that the future holds payrolls aplenty in the Mars game. In December NASA and Russian officials will meet in Washington to discuss a joint 2001 Mars mission that may make use of the shelved Russian rover. NASA itself has even more ambitious plans. With $100 million a year in Mars money promised by Congress, the space agency hopes to launch a pair of flights like Surveyor and Pathfinder every two years until 2005 or so.

"What we're hoping for," says Norm Haynes, a director of the Mars exploration program, "is a ship that will return a soil sample from Mars. That's the long-range goal of the program." Smaller ships, it appears, may not get a human being to Mars, but they may help bring a bit of Mars back to Earth.

--With reporting by Sophia Sears/Moscow and Dick Thompson/Washington

For more information about the search for life on Mars, see the TIME website at time.com/mars

With reporting by SOPHIA SEARS/MOSCOW AND DICK THOMPSON/WASHINGTON