The Life Lab

The spindly three-legged spacecraft sits silently on the dry, barren landscape. Suddenly, on command from controllers some 200 million miles away, the robot comes alive. A motor whirls; a slender, 10-ft. long arm reaches out, opens a small scoop and digs up some of the reddish soil.

Then the arm retracts, twists its wrist and drops the dirt into a small, mesh-covered opening on top of the spacecraft. Inside, analyzers go to work. Within a few weeks, the spacecraft sends a momentous radio message back to earth: Life exists on Mars.

This dramatic scenario is no longer confined to the daydreams of imaginative exobiologists.* Last week technicians at TRW Inc. in Redondo Beach, Calif., were finishing two miniaturized laboratories that will be able to test Martian soil for evidence of life. Next August, in the climax to NASA'S $1 billion Project Viking, two unmanned spacecraft will be fired aloft from Cape Canaveral. After an eleven-month journey, the Viking ships will swing into orbit around Mars. Each will release a lander containing a life-seeking laboratory. After descending with the aid of parachute and braking rockets, the first sterilized package should touch down on July 4, 1976, near the mouth of a 3,000-mile-long gorge that cuts across the Red Planet like a Martian Grand Canyon. The second probe is to land near the north polar cap. Both sites were picked because they could contain traces of water --essential to all terrestrial life.

The tiny laboratories are housed in 1-ft. cubes and weigh only 30 lbs. apiece. Each is crammed with 140,000 electronic components--including 122,000 transistors--40 thermostats, three tiny ovens, bottled radioactive gases, one pocket-sized chromatograph (used to identify the chemical component of the substance under study) and a small xenon lamp that can simulate sunshine. Costing $16.9 million each, the labs can perform three different life-detection experiments without any human help.

In one test, a small sample of Martian soil will be partially submerged in a nutrient-rich solution (called "chicken soup" by the experimenters). If any Martian organisms grow in the broth and give off carbon dioxide or other common byproducts of respiration-like life processes, instruments will detect these chemicals. In another test, soil will be exposed to a nutrient containing radioactive carbon 14. If any microorganisms consume the nutrient and give off carbon-bearing gases as metabolic wastes, those wastes will be radioactively "tagged" and readily identified. Lastly, a Martian soil sample will be exposed to xenon "sunlight" and a simulated Martian atmosphere of radioactive carbon dioxide and water traces. After five days, the atmosphere will be purged, and the sample will be baked to more than 1000DEG F. If vapors given off include any carbon 14, the scientists will be able to conclude that it was taken out of the atmosphere by Martian organisms in a process like terrestrial photosynthesis.

Even if Viking fails to detect living things, there is always the possibility that life on Mars is based on a chemistry different from that of any known life forms, or that it sought shelter even deeper in the ground as protection against the sun's deadly ultraviolet rays.

Should Viking find even the most primitive organism, it will help confirm what many scientists suspect: that life is not unique to earth and is probably commonplace throughout the universe.

* Who speculate about life beyond the earth.

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