Lifeboats for Astronauts

The laws of chance suggest that a manned spacecraft will sooner or later be stranded in space. Yet neither the U.S. nor the U.S.S.R. has a workable orbital-escape system (OES) for bringing stranded astronauts back to earth. Now, NASA engineers are designing a sort of space lifeboat that may give astronauts a reasonable shot at survival.

Developed by Caldwell C. Johnson, assistant chief of the Advanced Spacecraft Technology Division at Houston's Manned Spacecraft Center, the lifeboat is a rigid 400-lb. fiber glass shell lined with polyurethane foam and shaped like an old French bathtub--narrower at one end than at the other. It is 6 ft. long, 4| ft. wide, 21 ft. deep. Sheathed in a Johnson-designed nylon heat shield for re-entry into the earth's atmosphere, the craft is equipped with a swivel-mounted retrorocket, attitude-control jets, a transponder for ground control, a built-in oxygen supply, a parachute and a survival kit. Johnson envisions a typical Apollo spacecraft as carrying three such lifeboats in its service mod ule or equipment section.

"Womb at the Top." To abandon a foundering spacecraft, the astronaut dons extravehicular activity (EVA) gear, seals himself in the lifeboat and vents carbon dioxide and excess oxygen from his EVA suit to power the craft's attitude-control system. Face pressed against the porthole, he aligns his lifeboat with the horizon by firing the attitude-control jets. After sighting a landmark on earth with the reticle marked on the porthole, he aims and fires the retrorocket for 100 seconds, thus braking the lifeboat to a de-orbiting speed of 16,500 m.p.h. Then the retrorocket is jettisoned.

At an altitude of 50,000 ft., a bar-ostatically-triggered drogue parachute is released. In turn, the craft's main parachute is pulled open, and the astronaut descends, feet first, at 15 ft. per sec.--slow enough for a safe landing on either water or solid ground.

Skeptical astronauts call Johnson's OES the "Womb at the Top." Along with most NASA officials, they favor instead the "redundancy" approach of providing auxiliary systems to take over for any that fail. Moreover, as presently conceived, Johnson's lifeboat will be usable only on near-earth orbits. Even so, work on it has progressed further than on any other rescue system. Small-scale models have been repeatedly drop-tested in laboratory experiments. Computerized simulations of re-entry have uncovered potential flaws that are being corrected; Johnson's nylon heat shield has stood up well under rigorous tests at NASA's Langley Research Center. Next step: drop tests of the full-size boat in the earth's atmosphere, and then an unmanned test in space.

This file is automatically generated by a robot program, so reader's discretion is required.