Sen. Jake Garn (R-Utah), accusing President Reagan of showing "no leadership on space whatsoever," warned that the proposed U.S. space station lacks support and will have difficulty surviving the budget-cutting on Capitol Hill.

Garn, the first American politician to fly in space, also lashed out at his colleagues, saying they don't understand the implications of the complicated budget process on the space program and are "gutless" for their refusal to consider cutting entitlements and other "protected" programs such as veterans' benefits.

Addressing an audience of contractors and space program proponents at a seminar at the Dirksen Senate Office Building, Garn said, "The appalling thing to me is that there is no real support for space in this body.

"No one calls up, in any of these negotiations, and puts any pressure on my colleagues either in the House or the Senate to say we need more for space, except those that are directly involved: contractors. We hear from contractors. Well, that is not a wide base of support compared to those who lobby for food stamps."

He and others who spoke at the seminar, sponsored by a new lobbying group called Spacecause, called for a campaign to mobilize public support for the space program.

"I hesitate to say this but the past two administrations, including this one, which is mine and a Republican president I greatly admire, has shown no leadership on space whatsoever . . . . Other than the speech announcing the space station in my opinion there has been no follow-up whatsoever in communicating to the general public."

Garn is the ranking Republican on the Senate Appropriations subcommittee on HUD and independent agencies, which handles the National Aeronautics and Space Administration budget. Two-thirds of the subcommittee's programs are entitlements. Others are also protected in some way, leaving programs such as the space station as targets for the bulk of the cuts required by the recent budget "summit" between Congress and the White House. The decisions are expected by late next week.

"We have some nonentitlement entitlement programs, something known as the Veterans Administration, which are sacred," Garn said. "I say that as a member of the VFW {Veterans of Foreign Wars}, American Legion and as a retired military officer. But you simply don't touch them."

NASA estimates the space station will cost at least $14 billion; other estimates are the true cost will be more than twice that.