The nation's space program will be severely handicapped for years to come, even if the investigation of the Challenger explosion determines what caused the disaster and how to avoid it in the future, senior aerospace leaders say.
The loss of Challenger will cause a substantial and long-term shortage of launching capacity, the implications of which government and industry have begun to grasp fully only in the last week.
National security requirements for placing military payloads in orbit are likely to usurp more than 75% of the capacity of the remaining three shuttles for the next five years, intensive studies being conducted by NASA, the Defense Department and the National Security Council have found.
"This will cause a crunch," said Verne Orr, recently retired secretary of the Air Force. "The needs of the Defense Department are not flexible. There are times when we have to get to space."
Commercial and scientific launchings, meanwhile, would be slashed by more than half, thus some payloads that have taken years to develop and build will have to be put in storage for an indefinite period. Competition for the remaining shuttle space is expected to be fierce.
"There are going to be very severe problems," says Harry S. Dawson, a staff scientist on the House Space, Science and Applications subcommittee. "This is going to have a lot of ripple effects. There are clearly going to be satellites sitting on the ground for years as this whole thing unfolds."
The remedies available--building another orbiter and expendable rockets--would take a long time and be very expensive. Some cost estimates of a crash program to restore launching capacity reach as high as $10 billion over the next five years. That cost burden would come in an era of shrinking budgets and must be balanced against other compelling space program needs, such as the proposed space station.
None of the alternatives, however, can prevent the coming crunch. Like a freeway that is blocked during rush hour, the grounding of the space shuttle fleet will cause a massive traffic jam on the nation's principal route into space.
And, each month that the shuttle fleet remains grounded, the traffic jam will worsen. Some experts say that it is improbable that the shuttle will fly again this year. If it does not, a backlog of 13 missions will be left from this year alone.
Worse yet, when the remaining three orbiters finally resume operation, they will not have the capacity to launch all of the satellites scheduled from that time on, let alone reduce the backlog.
"This is the thing I was worried about," said Richard DeLauer, former Pentagon chief of research and engineering. "We really are committed to the space shuttle and now we are short one vehicle. There's no way around that."
Defense and NASA officials would not discuss the mission studies that suggest that the military will get three-fourths of the shuttle flights, but the computations are not difficult to understand.
The National Aeronautics and Space Administration had planned to fly the four space shuttles 16 to 24 times each year. The Air Force had agreed to fly at least eight of those missions.
The best NASA can expect now is to fly 12 missions each year, because it has suffered a 25% reduction of the fleet of orbiters. If the military continues to take its eight missions, it will have 75% of the available shuttle flights. Meanwhile, commercial and scientific missions would be cut from eight each year to four, a 50% reduction.
The Jan. 28 disaster is likely to force NASA to be more conservative in the frequency of launchings, and that will make the shortage all the harder to deal with.
Moreover, launching capacity is likely to be crimped further as NASA slows its efforts to increase the payload capacity of the orbiters by trimming weight off the spacecrafts and boosting the thrust of their engines.
Conservatism is dictated partly because the shuttle, since the accident, has a lower statistical reliability. The upshot is that NASA may choose to fly with fewer than seven astronauts aboard a shuttle, as it did early in the program. NASA may also curtail experiments by civilian scientists on flights.
"The ripple effects of this are much worse than we had calculated," said a top-level official of the space industry who requested anonymity. "No matter how you figure it, something has to give. It's commercial, plus NASA science, the planetaries and everything else."
That prospect is threatening to touch off a fight within the scientific community over whose projects are grounded.
"The interactions between the programs are ferocious," the official said. "Somebody will say 'I've got first priority' and everybody else will groan, because they will have to slip all of their programs by some amount of time, at quite a cost per month.