President Reagan yesterday told graduates of the United States Air Force Academy they are standing on ''America's next frontier - the vast frontier of space.''
But military men and women looking at the strategic possibilities of space also are standing on the threshold of considerable controversy over the Reagan administration's plans for that frontier. This is the continuing public and political unease over weapons designed to destroy satellites or protect against the threat of nuclear missile warheads.
Discomfort over such advanced ''Star Wars'' systems is reflected in recent congressional action. The House of Representatives by a 57-vote margin has voted to continue a moratorium on the testing of antisatellite (ASAT) weapons against targets in space. The House Armed Services Committee also cut the administration's $1.8 billion request for antiballistic missile research by $407 million.
Lawmakers were reacting to a recent Congressional Budget Office report on the administration's long-range plans for strategic defense spending. Annual funding would jump nearly fourfold over the next two years, the CBO reported, with $26 billion to be spent over the next six years. And this, the CBO added, may not include related expenses tucked elsewhere in the Pentagon's budget.
Members of Congress voting against the administration also were swayed by a background paper prepared for the Office of Technology Assessment, a congressional agency. Written by Ashton B. Carter of MIT, this report concluded that ''the prospect that emerging 'star wars' technologies, when further developed, will provide a perfect or near-perfect defense system . . . is so remote that it should not serve as the basis of public expectation or national policy about ballistic missile defense.''
Aside from concerns about the cost and technical feasibility of rendering nuclear weapons ''impotent and obsolete,'' as the President has called for, serious questions have been raised about the administration's intent in seeking such a capability and also about the effect of space weapons on superpower stability.
Air Force Lt. Gen. James A. Abrahamson, director of the new strategic defense initiative organization within the Pentagon, says he recognizes the technical difficulties in developing foolproof missile defenses.
''The system must not be regarded as a 'paper tiger' by the Soviets if it is to serve as an effective deterrent to nuclear war,'' he told a congressional panel recently. ''Therefore, its credibility must be based on a demonstrated capability to manage the surveillance, tracking, and intercept actions over the multitiers of this complex system.''
But General Abrahamson also says that the goal remains ''to provide security for the people of the United States and our allies.''
And he notes that strategic defenses would not eliminate the need for offensive nuclear weapons, at least for the foreseeable future.
One who takes sharp exception to this view is Robert M. Bowman, a retired colonel who once headed space weapons programs for the Air Force and now is president of the Institute for Space and Security Studies.
''To pursue an extremely effective defensive shield while retaining offensive weapons carries an enormous danger of provoking war or causing one by accident, while yielding very little hope of providing sufficient protection to enable the nation to survive,'' he argues.
The US has plenty of nuclear retaliatory capability to deter a Soviet first strike, Dr. Bowman says, without needing to violate the Antiballistic Missile (ABM) Treaty by deploying space-based systems. Such a systems could never be ''leak-proof,'' he maintains, and in conjunction with accurate new offensive weapons like the MX, Pershing II, and advanced Trident missiles could be viewed as part of a first strike.
Instead, Bowman says, the US should enhance deterrence and increase stability by providing ''point defense'' protection for land-based ballistic missiles (the most vulnerable leg of the strategic triad). The ABM Treaty allows the Soviet Union and US to deploy 100 ground-based interceptor missiles to defend against nuclear attack.
The Soviet Union has 64 such rockets; the US dismantled a similar system some years ago.