Cheers, Challenger

ONCE again American astronauts and Soviet cosmonauts have demonstrated the unique advantage of having people in space. No robots, however cleverly constructed, could have saved the Challenger and Salyut missions. Chief shuttle mission scientist Eugene W. Urban credits the adaptability and ingenuity of the astronauts, working with the scientific team on the ground, for turning what could have been substantial failure into more than an 80 percent success.

Likewise, the Soviet cosmonauts recently showed both skill and bravery in reviving the dead Salyut space station. With no electrical power, Salyut's automatic systems could not aid the cosmonauts in docking. Moreover, the temperature had fallen so low within Salyut that even the water supplies were frozen. Now that station is back in service within the Soviet manned space program.

These achievements give a useful perspective on manned spaceflight at a time when the United States, in particular, is reassessing this activity.

The shuttle system is an outstanding technical success. Yet it struggles to become a commercial success. Competition for launch customers is stiff. Europe's Arianne unmanned rocket already claims a large share of the market. The Soviet Union and China have also announced they have rockets for hire. Moreover, fledgling private US rocket-launching companies complain that the subsidized shuttle is giving them unfair competition.

Critics within the industry and within Congress openly wonder whether the shuttle program may not be a costly boondoggle. They question the wisdom of pushing ahead with NASA's new goal of orbiting a manned space station by 1992. Why not wait until the commercial value of such a station is more clearly defined, they ask.

These reservations miss the essential point, which the recent US and Soviet space exploits have demonstrated: People add a dimension to spaceflight which no machine can duplicate. They bring an intelligence, versatility, and adaptability that can cope with emergencies. They can ensure success even when vital equipment has failed. And they can carry out tasks too complex for any machine likely to be designed in the foreseeable future.

Manned spaceflight is in its infancy, however. Human beings are still learning how to live and work in space. They have scarcely begun to explore their full potential for extraterrestrial achievement. It is mistaken to try to justify the development of manned spaceflight on commercial grounds at this stage. The US shuttle program and space station project should be seen for what they really are -- essential first steps in opening a new arena of human activity. This is how the Soviets view their Salyut s pace station. The principal justification for both programs is as an investment in the future, not as a commercial operation with a short-term payback.