America's space shuttles may be grounded, but its astronauts are busy. ``We're really not `on hold' in that everybody is working things,'' says Bruce McCandless, a 20-year veteran of the corps. His eyes sparkle as he describes the ``thing'' he's working. He is training to launch the Hubble Space Telescope.
With its ability to see across the universe, many scientists think the telescope could prove to be the most influential scientific instrument yet orbited. This buoys Mr. McCandless's hope that his mission ``will be one of the early ones after we get flying again. . . . The scientific community is extremely anxious to get the telescope up and operating.''
That community is also extremely eager to get the Galileo probe on its way to Jupiter. The grounded mission's 1986 launch window has just slammed shut. With it has gone the opportunity for a close-up study of the asteroid Amphitrite.
The contrasts between these two scientifically valuable missions symbolize the ambivalence with which American space scientists view the shuttle. They welcome the new capability that the space telescope represents. Yet the uncertainty over Galileo's future deepens their chagrin at being forced to use the shuttle for virtually all major space-science research.
``The unique contribution of the space shuttle to science is yet to come,'' says historian Joseph Taterewicz of the National Air and Space Museum. As he explained to the Smithsonian News Service, ``That contribution will come from large, long-lifetime spacecraft that require periodic attention for maintenance and improvement.'' The space telescope is only the first of these.
Astronauts working on the National Aeronautics and Space Administration's proposed space station would consider such maintenance routine. The station would also extend the space laboratory concept, which the shuttle provides for short periods, to give scientists a capacity for long-term research on orbit. NASA's university-based Task Force on the Scientific Uses of the Space Station sees such laboratories becoming ``an active, vital part of the US and international science establishment.''
American space scientists would probably welcome such new capabilities unreservedly were other valuable space science projects, such as Galileo, not suffering. NASA's overall budget has been held almost constant at $7.5 billion (1986 dollars) since 1974. During the same span, the agency's outlays for space activities have been held almost constant at about $5 billion to $5.5 billion a year (in 1982 dollars). Space science has suffered as shuttle development claimed more of the limited funds. To help the shuttle prove its utility, NASA persuaded the administration six years ago to mandate that the shuttle launch virtually all major scientific satellites and space probes.
A Titan rocket with a Centaur hydrogen/oxygen-powered upper-stage booster could have launched Galileo as it did the two Voyager spacecraft in 1977. A new Centaur has been developed to boost Galileo-scale scientific and military craft from shuttle altitudes to higher orbits or into interplanetary space. Unlike the space telescope, Galileo with this untried Centaur upper stage has hazardous propellants and pyrotechnics.
Now NASA has admitted that it has not adequately assessed this danger and has suspended plans to use the new shuttle-based Centaur. It could cost an extra $1 billion to $1.2 billion to switch Galileo and two other authorized planetary projects to Titan/Centaur rockets. At this writing, it was unknown whether NASA could absorb such a cost.
Thus Galileo could join what space scientist James A. Van Allen of the University of Iowa has called ``the slaughter of the innocents'' -- worthy space-science projects that have been denied, postponed, or curtailed because of the shuttle's drain on NASA funds and the decision to phase out unmanned launch vehicles. Dr. Van Allen is concerned that the commitment to build the space station will further crimp NASA funds and continue the carnage.
Even if Galileo is launched next year, the National Academy of Sciences notes that ``at least a full decade will have lapsed between the launching of the Voyagers in 1977 and the next major scientific mission of the United States. . . . Seven full-scale scientific missions have been or are being prepared for launches that were scheduled during the next two years. Several others are waiting in line behind these.'' Now no one knows when any of these will be launched, if ever. The decision to rely on the shuttle ``has been devastating for space science,'' the academy says.
It seems unlikely that American space science can recover its vitality, let alone its world leadership, without raising NASA's budget. NASA now admits it needs unmanned rockets as well as the shuttle and must find ways to pay for them. Administrator James C. Fletcher says that ``it is not likely the White House will weaken in its resolve'' to have the space station.
Moreover, the administration seems ready to request a replacement for the Challenger, which NASA needs to build the space station.
NASA's present budget cannot handle all this and maintain a vigorous space-science effort. Jesse W. Moore, director of the Johnson Space Center, warns that if NASA has to buy a fourth orbiter without new money, ``it's going to cause us, I think, some very severe pains in other program areas.''
Third of 10 articles. Tomorrow: Factories on orbit.