Science & technology
THE LILLIPUTIANS WHO MAY CONQUER MARS
Dressed in corduroy Levis and T- shirts, Bill Kaiser and his team of fresh-faced engineers look like high school students determined to win first place in a science competition. But this is no school project. Working out of cluttered, windowless offices at the Jet Propulsion Laboratory in Pasadena, Calif., the 35-year-old Kaiser and other scientists are hatching plans to invade the planet Mars. The invasion force: two dozen small, supersmart unmanned spacecraft that would scour the red planet for signs of ancient life.
JPL's proposed minimarauders could open a new era of space exploration. For decades, NASA has staked its fortunes on huge, high-risk ventures such as the space shuttle, the space station, the Galileo spacecraft to Jupiter, and other megaprojects that cost billions of dollars. A proposed $500 billion manned mission to Mars by the year 2025--which has the backing of the Bush Administration--would be, by far, the most extravagant plan yet.
But with their research funding under attack by Congress and huge projects siphoning off resources, some NASA labs are now hoping to sell the space agency on a better idea: JPL, NASA Ames Research Center in Mountain View, Calif., and others envision a new generation of small, inexpensive probes that minimize the costs of space travel--and lower the price of failures. On Aug. 29, the rival labs were to ask NASA headquarters for money--up to $1 million--to go forward with advanced research. This is "a fundamentally different approach to space travel," says Elizabeth Prestridge, a spokeswoman for the National Space Council, a policy group headed by Vice-President Dan Quayle.
The smaller craft would be more than simply cheaper to lift into orbit. Crammed with microrovers and micro-instruments to measure the planet's atmosphere and its makeup, JPL's version of the so-called Mars Space Network would deploy equipment 1,000 times smaller yet hundreds of times more sensitive than instruments used on today's spacecraft. That, says JPL chief scientist Moustafa Chahine, will prove "absolutely revolutionary. This isn't a distant dream. We have the technology."
SMALL BIRDS. Money is another story. JPL has to convince NASA that its micromission to Mars is worth the more than $1 billion it would cost. At the moment, a cheaper, lower-tech plan from Ames, called Mars Environmental Survey(MESUR), enjoys more support at NASA headquarters. The MESUR mission would cost $800 million and would send 16 landers with simpler, larger instruments--and no rovers.
Whether NASA eventually opts for the JPL or the Ames Mars mission, the push toward small spacecraft seeks to exploit the microtechnology that has already transformed computers, stereos, and televisions into laptops, Walkmans, and pocket TVs. The Pentagon has begun developing microsatellites for the Strategic Defense Initiative, and NASA recently said it may modify plans for its Earth Observing System, using a fleet of smaller birds instead of a few huge satellites.
NASA is considering the first launch of robotic Mars explorers in about 10 years, before tackling the goal of landing humans on Mars. Under the Ames plan, a medium-size Delta rocket would launch a cluster of four relatively small, 330-pound, pancake-shaped craft that would make their way independently to Mars on an 11-month, 100-million-mile journey. The landers would deploy a parachute and an airbag to smooth the touchdown.
Instruments aboard the landers would probe the atmosphere, continuously beaming data on temperature, humidity, and winds back to earth. They would also measure the intensity and frequency of seismic activity. As more landers took up positions across the planet, scientists would be able to piece together an increasingly coherent picture of Martian weather patterns, seasons, and the planet's interior structure.
JPL's plan is technologically even more ambitious, which helps explain its higher cost. A smaller rocket would boost a cluster of four, 290-pound egg-shaped craft. They would travel as a unit before separating in Mars orbit to head for different spots on the planet. In both the Ames and JPL scenarios, two of the four probes would land on Mars's North and South poles to sample ice and frozen gases.
Once these probes had landed, a scene out of science fiction would unfold. The tops of the JPL landers would fold out to deploy a pair of rovers. Resembling radio-controlled toy cars, they would spread out for a half-mile to deploy more sensitive instruments away from interference from the lander. Light-sensitive chips and microprocessors would help the rovers steer clear of rocks and deep ravines. "We want our little rovers to learn as they roam around the surface," says Chahine. "If they can't get around an obstacle, they won't make the same mistake twice."
The first flock of rovers would deploy microsize scientific instruments designed by Kaiser's team. Seismometers no bigger than a pack of cigarettes wouldmeasure the slightest movements far below the Martian crust. Tiny spectrometers would analyze the planet's surface composition.
NATURE HUNT. Within about six years of the first landing, as many as 24 microstations would dot the surface of Mars, sending back reams of data from the planet's deep canyons, ancient dry lake beds, and 90,000-foot mountain peaks. In later flights, miniature sanders, shovels, and microscopes would sense, poke, and photograph patches of Mars's surface in search of fossilized microorganisms and other clues to the planet's past. The lander would relay data to orbiters and, from there, back to earth via JPL's Deep Space Network.
Because it takes radio signals 40 minutes to make a round trip from earth to Mars, sensors on board the landers would have to take over in the event of navigational failures, telling the rovers to halt rather than hurtling down a ravine. But where failure of a key part on a one-of-a-kind spacecraft such as Galileo or the Hubble telescope can cripple the mission, the complete loss of one rover--or even one of the Ames landers--wouldn't send its designers heading for the Maalox: Each would represent only a small fraction of the overall mission's cost.
Still, the scientists are planning on plenty of snafus. Next month, JPL engineers hope to begin testing prototype microrovers in the rugged deserts outside Los Angeles. "There are going to be failures," acknowledges Charles Elachi, assistant director of space science. "We're constantly pushing the edge of our technology." NASA is still captivated by putting humans in space. But as manned missions become increasingly complex and expensive, the technological push for ever-smaller robotic spacecraft will no doubt play a growing role.Eric Schine in Pasadena, Calif.