MANNED spaceflight has reached a critical juncture. Its technology is obsolete. Its present utility is unclear. Add to this the current squeeze on national budgets, and even spaceflight boosters say it's time to put dreams of moon bases and Mars exploration on hold and rethink the enterprise.
``The '90s are going to be a decade of rethinking and regrouping,'' says Thomas Paine, former administrator of the National Aeronautics and Space Administration (NASA).
As chairman of President Reagan's national space commission, Dr. Paine had outlined a bold program to take humans back to the moon and on to Mars. But as a member of the White House commission that released its review of the space program last week, he urges NASA to use this decade to build a new spaceflight capability that is more cost effective and reliable than the present shuttle transportation system.
Ray Williamson, lead space analyst at the congressional Office of Technology Assessment (OTA), agrees. He explains: ``Humans to Mars is much more a question of when than if. But a realization is percolating through the space community that we had better back off.'' He adds, ``I think the budget issue will force rethinking as to the balance between manned and unmanned missions.''
Congress says cut back
The Senate/House conference that wrote the final 1991 US budget ordered NASA to scale down the Space Station Freedom and cut all funding for President Bush's Space Exploration Initiative (SEI) to send humans to the moon and Mars. The conference report said flatly that ``initiation of a focused [SEI] program is not possible at this time.''
Similar reservations are heard in Europe, as Roy Gibson, former director general of the European Space Agency (ESA), explains in the current issue of the British Interplanetary Society Spaceflight magazine. He warns: ``We are quite likely to cause European ministerial support for space to decline further if this moment is chosen for a clarion call for a new mammoth [manned] space spectacular.''
Even in the Soviet Union, spaceflight seems to be losing its luster. Information on Soviet space planning is sparse in the West. However, Mr. Gibson notes that some spokesmen have discussed budget cuts and a reduced manned-flight program. ``It would be very surprising if this were not so,'' he says.
Summing up, Gibson concludes that ``all major space players will be forced, either collectively or separately, to reassess their major programs.''
This reassessment is driven partly by budget constraints and partly by rearranged priorities. Gibson notes that, in Europe, ``space has slipped downwards'' in national priorities while ``cleaning up the environment is at, or near, the top of many countries' priority list.'' Space applications that contribute to environmental management are likely to be favored over manned flight. That includes ESA's participation in the Space Station Freedom program as well as its own Hermes program to develop a small manned spacecraft.
Earth probes boosted
The US Congress gave NASA's Earth-probes program a 124 percent increase over the administration's budget request while cutting, or in some cases eliminating, funds for manned spaceflight programs.
There also is wide recognition in the US that the shuttle is inadequate. The congressional budget conference report expresses serious doubts about its ability to support space-station construction and fulfill the other missions envisioned for it.
The White House review panel is equally skeptical. It urges NASA to restrict shuttle missions to those where human skills are truly needed - as in Hubble telescope repair or research in the shuttle-carried Spacelab.
The panel further urges that NASA build a new launch capability featuring a heavy-lift unmanned rocket that could put most payloads - including space-station components - into orbit.
``The shuttle is not a robust system,'' says OTA's Williamson. He adds that the OTA, like the White House panel, has warned that NASA could lose another orbiter, which would cripple the system. He forecasts that ``in time, we'll learn how to make spaceflight systems more robust.''
Paine says that developing the recommended versatile heavy-lift launch rocket is the key. Then, he explains, with the way technology is advancing in all aerospace areas from materials to flight systems, he expects a powerful new spaceflight system to emerge. ``Everything says that, in the next century, we're going to be able to fly through space with a lot more ease. Then going back to the moon and exploring Mars will seem a natural and feasible thing to do,'' he says.