The explosion of the shuttle Challenger nearly two years ago threw the U.S. space program into such staggering disarray that officials have shied away from predicting when the program would get back on track, much less undertake new ventures. Though the shuttle's return to service is still at least six months away, NASA officials last week managed to look beyond that crippling disaster and announced plans for two ambitious programs for the next decade. In 1989, the space agency declared, it will finally launch its long-delayed unmanned Galileo project to Jupiter, a 2.3 billion-mile mission that is expected to last eight years. NASA also awarded four contracts for the construction of the long-planned space station that will serve as the nation's first permanent outpost in space.
While the projects each offer exciting prospects, they amount to something less than the fully rethought agenda that many space experts have urged on NASA. For one thing, both depend on the restored health of the shuttle program, which will be used to launch the Galileo mission to Jupiter and provide transport for the components of the space station. For another, both the space station and the shuttle program confront major budget uncertainties.
The timing of last week's announcements reflected mounting external pressure on the beleaguered agency. The Galileo mission has an approaching launch "window" that will last only six weeks in the fall of 1989. As for the space station, NASA Administrator James Fletcher faced the growing impatience of firms competing for contracts that had each spent about $75 million for preliminary design proposals.
The most striking new feature of the long-planned Galileo mission, first scheduled for 1982, is a looping itinerary that will provide momentum for the spacecraft by utilizing the gravitational fields of Venus and the earth. This "slingshot" routing became necessary when NASA officials decided that the rocket originally scheduled to boost the craft from a shuttle cargo bay could pose a hazard; it was replaced with a safer solid-fuel booster. Another change in plans involved putting extra gold sheeting on the Galileo spacecraft because of the scheduled pass close to the superhot atmosphere of Venus.
On its long voyage toward Jupiter, the spacecraft is scheduled to pass within 620 miles of the asteroids Gaspra and Ida, the first such close encounter in the annals of interplanetary travel. Then, five months before reaching Jupiter near the end of 1995, Galileo is to release a 730-lb. probe that will become the first man-made object to penetrate the gaseous atmosphere of the planet. Its instruments are expected to transmit data on the Jovian atmosphere for about 75 minutes before being silenced by the planet's intense atmospheric pressure. Galileo is next scheduled to settle into a two-year-long orbit of Jupiter that will enable it to make detailed studies of the planet and four of its moons.