NASA has plans but not funds for new planetary space probes

A QUARTER-century ago - Dec. 14, 1962, to be exact - the American Mariner 2 spacecraft flew by Venus to open the era of solar system exploration. The array of United States, Soviet, and international missions that followed has been a spectacular collective achievement. Yet, in saluting the Mariner 2 anniversary recently, Leonard Fisk, NASA's associate administrator for space science and applications, said, in effect, that ``we ain't seen nothing yet.'' NASA, he declared, intends ``to conduct a tour de force of the solar system in the 1990s.'' He explained that this means ``to place an orbiter about most of the accessible bodies in the solar system - that's Venus, the moon, Mars, a comet, Jupiter, and Saturn.''

That's quite a statement for an agency that, in Fisk's words, ``has the best space science ... program on the ground.''

Indeed, there is much to make US planetary scientists gloomy. They haven't launched a mission since 1978. Several of the new missions Fisk cited have yet to be approved, while the rest have been repeatedly delayed. Uncertainties about future funding and about opportunities to launch missions with either the shuttle or unmanned rockets are worrisome.

Fisk says he understands why planetary scientists might feel some pessimism. But, he adds, ``Do I share it? Absolutely not!'' He says he feels momentum building within NASA to get the shuttle flying again in June. He sees determination to use it, together with a new fleet of unmanned rockets, to give the United States ``the best space science program ... in space'' once again. ``It will be exciting,'' he declares, ``and it will be second to none.''

If there is sufficient leadership within a new administration and Congress to provide adequate and consistent funding, the planetary program NASA and its scientific advisers have planned will indeed be breathtaking. Missions awaiting launch include Magellan to map Venus by radar; Galileo to study Jupiter's satellites and send a probe into its atmosphere; and Mars Observer to survey that planet's surface chemistry and atmosphere. Missions awaiting approval include the Lunar Geochemical Orbiter to assess moon resources; Comet and Asteroid Flyby; and Cassini to orbit Saturn.

These missions would complement an intensive Soviet exploration of Mars in a series of missions starting next year with a probe of the martian moon Phobos. Working under the agreement of space cooperation signed last April, the two nations hope to coordinate their planetary programs. Taken together, Fisk notes, such coordinated programs ``will provide a broad range of information on a broad range of planetary objects.''

This would be a challenging second phase of the exploration that Mariner 2 began. But its realization depends very much on the willingness of the next administration to give the United States space program the effective leadership the Reagan administration has failed to provide.

A Tuesday column. Robert C. Cowen is the Monitor's natural science editor.