GRANDIOSE visions of joint US/USSR manned expeditions to Mars have filled news pages and television screens. It's an exciting prospect, but such proposals will remain pipedreams until some hardheaded planning is done to answer fundamental questions. Chief among them is the practical one: How do we get there from here? No less important is this concern: How can we really determine if the ``new'' Soviet Union is trustworthy enough to base our own manned spaceflight plans on?
These concerns can be addressed by a specific space activity which as of now is not being seriously discussed in public by policymakers. This involves ambitious near-term joint manned activity by American astronauts and Russian cosmonauts using the NASA space shuttle and the Soviet Mir space station. No major new hardware needs to be developed or paid for.
We've already overcome the psychological barrier for such missions. The image of the ``space handshake'' from the Apollo-Soyuz docking in 1975 is almost as memorable as Neil Armstrong's first moon steps. It marked another ``giant leap'' in space history, with profound implications for human history down on Earth.
That linkup showed that the Soviets, even long before glasnost, could be open enough to satisfy stringent NASA safety requirements. In following years it also became clear that the Soviets had not used the program as a cover to steal American technology. They pushed their own home-grown space engineering to new heights based on accumulated flight experience.
That American-Soviet project was never supposed to be a one-shot program. Original plans called for follow-on missions, and in 1977 the Carter administration signed an extension of that agreement. Although the Reagan administration allowed this to lapse, by 1985 the White House and NASA administrator James Beggs were both announcing support for a shuttle visit to a Soviet space station. Then came Challenger, and the ``policy review'' typical of any new president's first months in office.
But now time's a'wasting, as they say in Houston. To provide information to support governmental decisions in the early 1990s, joint manned missions need to begin soon and continue indefinitely.
The easiest way is for an American astronaut to ride as a guest aboard a Soviet Soyuz, in exchange for flying a Soviet aboard the space shuttle. Both nations already know how to accommodate foreign passengers aboard their space vehicles, since eight non-US spacemen have ridden shuttles and a dozen countries have had guests aboard Soyuz launches.
Such exchanges also promise practical benefits. An American doctor could test medical monitoring equipment developed for NASA's long-duration Freedom space station. And the Soviets could use their opportunities for medical research, perhaps by flying one of the three physicians (all women) selected for cosmonaut training in 1984; the Soviets might send a space shuttle test pilots now developing techniques for their delayed Buran spaceplane.
Actual linkups between spaceships are also surprisingly easy. NASA adopted the sea-level atmospheric environment long in use by the Soviets, eliminating the need for special ``docking modules'' used by Appolo-Soyuz. The Mir space station is manned essentially full time, providing a continuous opportunity for dropping in. NASA space shuttles regularly venture into high-inclination orbits which would require only minor launch adjustments to be fully compatible with a Mir rendezvous.
This is how easy it might be. Planned shuttle missions carrying radar laboratories could be modified to include a day or two of joint orbital operations. The Soviets are building their own jet backpack so both astronauts and cosmonauts could fly from one nearby vehicle to another for brief visits, testing the techniques and equipment for space rescue and further measuring the Soviet's candor and cooperation.
Actual docking hardware could be developed from existing space shuttle systems, such as the airlock extender built for use on Spacelab. The Mir will be equipped with an androgynous docking port early next year, and a NASA shuttle could attach itself there, to be supplemented with electricity from Mir's solar panels.
More exciting prospects open up once a Soviet-compatible docking unit is available. A Soyuz-TM could rendezvous with a shuttle, dock, and then separate again trailing a tens-of-miles-long kevlar tether to test the dynamics of such revolutionary structures. The orbital lifetime of a NASA Spacelab mission with one or two Soviet scientists aboard could be extended for weeks by the docking of a new-model Progress-M cargo ship carrying cryogenic fuels for the shuttle's electrical generation system.
Eventually, personnel and hardware could be exchanged both on the ground and in mid-flight, as the shuttle provides the Soviets with a much-needed ``down-cargo'' capacity and the Mir provides NASA with a valuable platform for early extended testing of space station components.
Beyond these practical uses, there are the international implications. Joint US/USSR missions, perhaps beginning under the auspices of the planned International Space Year in 1992, would be a true test of the Soviet willingness and ability to play by the rules of international cooperation. The bureaucratic mechanisms and much of the specific hardware is already in place to support such a determination.
The Bush administration appears serious about manned expansion into the solar system, while White House foreign policy advisers also are seeking realistic ways to gauge Soviet intentions. This may be a way to do both, and to determine whether grandiose visions can come true. The cost is low, the risk is low, and the potential payoff is interplanetary in scale.