THE FIGHT NOW under way on capitol Hill over the Jupiter Orbiter Probe is a small and rather curious one, but it goes to the heart of what this nation's space program ought to be. Both the House and Senate voted earlier this year to authorize this particular project, which would put a spacecraft in orbit around Jupiter in 1984 and drop a probe into ints atmosphere. But the objections of a House Sppropriations subcommittee now threaten to kill the project before it gets started.

Two months after the House approved the project--and 11 days after the Senate also did--the subcommittee, headed b Rep. Edward P. Boland (D-Mass.), cut the funds for it out of next year's space budget. The stated reason was "budget priority," and members of the House were told the program was "very expensive." The Senate put money for the project back into the budget, but the House conferees, headed by Rep. Boland, have refused to reconsider their position and are taking the matter back to the House floor for instructions.

What is involved here is the ability of a subcommittee chairman, who thinks this country is spending too much money on space programs, to veto a worthwhile, already-appreoved project simply because it is vulnerable. Jupitr Orbiter is a low'cost item, as space missions and most other government projects go. Its start-up costs, which are the ones in difficulty, are $20.8 million. Its estimated total cost is $280 million. Becuase it is small and becuase it lacks the drama of manned space missions, it has little political support. The big items in the $4 billion space budget, like the space shuttle, generate many jobs and much backing from members of Congress. Rep. Boland, who can't curtail the big projects because of that support, picked htis one to slice out of next year's budget as a demonstration that the space crowd can't get everything it wants.

Unfortunately, jupiter Orbiter is not an isolated undertaking. It is the logical next step in a systematic exploration of the solar system that began some years ago. Viking it still out there looking at Mars. Vovagers and Pioneers are schedeled to leave during the next three years to explore Jupiter, Saturn and Venus. The Jupiter Orbiter, designed as the next in the series, is scheduled for launch early in 1982 for a 20-month-long look at that planet. Dropping it out of the sequence, or postponing it, disrupts the orderly scheduling and effective use of skilled personnel that this research requires.

This nation ought to use its space capability to gain more basic knowledge of the universe as well as to engage in practical--and exciting--applications of earth-orbiting satellites. Congress accepted that view of our role some years ago, or so we had thought. If it now upholds one subcommittee's veto of this project, it will be turning its back on its own commitment to space program that makes scientificsense.