WHEN NASA's Mariner 2 flew past Venus a quarter-century ago, an era of planetary competition opened between the United States and the Soviet Union. Now the two nations are talking about exploring the solar system together. Moscow's formal request for American help with a 1994 Mars mission is a welcome first step toward what could become official coordination of national space programs rather than competition.
The Soviets asked NASA to put an extra radio relay on the Mars Observer craft it plans to put in orbit around Mars in 1992. When the Soviet mission arrives, Mars Observer could help send back its data, which American scientists then would share. This may seem a small favor for the United States to grant. But the US-Soviet space agreement signed last April is a framework for wide-ranging coordination in space research. If this first step to follow the agreement is satisfactorily arranged, other cooperative projects will likely follow.
This gives the US an extra challenge as it prepares to restart its spaceflight program next year. Not only does NASA have to regain access to space for its own sake, it must also be ready to act as an effective international partner.
Other Western space-faring nations are already working with the Soviets as guests on various space science missions. In fact, the data Mars Observer would relay will be gathered by instruments carried by a French-designed balloon floating in the martian air. These Western nations are also counting on NASA's space station program - in which they are partners - for manned spaceflight experience in the late 1990s. If NASA can't perform effectively on the international scene, its Western partners will inevitably be drawn into closer working relationships with the Soviets. Clearly, it would not be in the best interests of the United States to have to go it alone in space.
Yet, if NASA is to be a credible partner, it needs a long-term program on which other nations can rely. This, in turn, requires leadership, which the White House and Congress have so far failed to provide.
NASA will probably get the shuttle flying again next year. It will start the construction phase of its space station. But without a clear commitment to support for an agreed long-term program, NASA's ability to carry out international commitments - including cooperation with the Soviets - will be uncertain.
The US space program has an overriding need for presidential leadership. If the Reagan administration can't provide it during its final year in office, then the next administration must do so.