WHEN a US-Western European spacecraft passes through the tail of the Giacobinni-Zinner comet on Sept. 11, a Soviet observer will join NASA mission controllers to watch the action. The craft's experience in traversing the dusty comet environment could help Soviet controllers better guide their own Vega probes when they inspect Halley's comet next March. The Soviet presence at the NASA Goddard Space Flight Center in Maryland would also symbolize the fact that the United States and the Soviet Union have continued to cooperate informally on some space projects even though the relevant treaty has lapsed. Now, there is new hope within the US space community and Congress that a renewal of full formal space cooperation can be worked out at the November summit meeting.
That hope inspired many speeches and corridor discussions during recent activities -- including a conference on Mars exploration -- held in Washington to commemorate the 10th anniversary of the Apollo-Soyuz joint US-Soviet orbital flight.
As US Rep. Bill Nelson (D) of Florida told a public symposium at the Smithsonian Air and Space Museum, there is growing, if cautious, support in Congress for renewed space cooperation with the Soviets. Space is seen as an area where the two superpowers can find worthwhile projects to work on jointly despite their mutual suspicions and rivalry, and despite starkly different political systems and cultures.
This rising expectation underlies Congress's joint resolution which President Reagan signed last October committing him to seek such cooperation. It also underlies the companion resolutions introduced two weeks ago by Mr. Nelson and by Sen. Spark Matsunaga (D) of Hawaii, urging the US to seek the partnership of the Soviet Union and other nations in an International Space Year of wide-ranging space research. The ISY would start in 1992, the year marking the 500th anniversary of Columbus's discovery of A merica as well as the 75th anniversary of the Russian Revolution.
That year is also the 35th anniversary of the International Geophysical Year, which saw a similar international effort to study Earth. In fact, the first Soviet Sputnik and the first US Explorer and Vanguard satellites were officially part of the IGY program.
Some hopes for joint projects are quite ambitious. A manned mission to Mars was a major theme of the Mars conference held two weeks ago by the American Institute of Aeronautics and Astronautics and the Planetary Society. In fact, said Planetary Society president Carl Sagan, the prospect of the Sovet Union and the United States doing something extraordinary together on behalf of all humanity would be ``a central justification'' for landing in another world.
No one knows how realistic a prospect that may be. Space togetherness with the Soviets would have its difficulties, as both the congressional Office of Technology Assessment (OTA) and the US National Aeronautics and Space Administration head, James Beggs, have recently explained.
Neither nation would want the other to have access to militarily sensitive technology. There would be a risk of one nation's being left holding the bag if the other unilaterally pulled out of a joint project. Such risks could be ameliorated to some extent by having each nation supply entire working modules of space hardware. Such equipment would be valuable in its own right, whether or not a joint mission took place. Also, militarily sensitive aspects of their manufacture would not have to be divulged.
There are questions of who would benefit most from a joint venture. This would have to be decided project by project. But as the OTA, Congressman Nelson, and others point out, a joint project is a window through which the United States can learn about aspects of the Soviet space program which might otherwise remain secret.
Finally, OTA may well be right to note that the toughest question of all to answer is that of the foreign-policy objectives to be served. Are joint space projects a means of lessening tension or a result of lessened tensions? President Reagan let the US-USSR space agreement lapse in 1982 to show displeasure with Soviet actions. Thus, any renewed formal space cooperation has to come within a larger context of mutual US-Soviet accommodation.
The continued informal cooperation shows that there is no dearth of at least modest scientific projects of mutual interest. For example, the US provided crucial tracking for balloon-borne probes sent into Venus's atmosphere by the Soviet Vegas as they swung around the planet toward Halley's comet. Next month, US experts will meet with scientists from a number of countries in Toulouse, France, to study the results sent back by these probes -- a joint French-Soviet project -- and by two other Soviet probe s that landed on the planet's surface.
Certainly a formal and more visible cooperation even on such modest scientific projects would reflect at least a small lessening of tensions. That, in itself, could be a worthwhile foreign-policy objective. At the other extreme (and as wishful as it now may seem), might there not also be some merit in beginning to explore Carl Sagan's dream of a joint expedition to Mars?
Sagan notes that on such a mission -- far from earthly help -- the lives of the American astronauts would depend on the efficient, intelligent work of the Soviet cosmonauts. Conversely, the cosmonauts' success and survival would depend on the performance of the Americans. Sagan asks whether that situation is so different from that on Earth today, with the nuclear standoff between the US and USSR. Perhaps in meeting the challenges of such a mission the two nations, and others that may work with the m, could learn some lessons that would be valuable right here on Earth.
A Tuesday column. Robert C. Cowen is the Monitor's natural science editor.