Sometime soon, an F-15 Eagle jet will scream down the runway at Edwards Air Force Base in Southern California, pull its nose up into a near vertical climb, and head for the stars.
As the Earth drops away and the supersonic interceptor pushes more than a dozen miles upward, the pilot will fire an 18-foot rocket that in turn will blast several hundred miles into space.
This will be the first test launch of the new US antisatellite (ASAT) weapon, a major development in strategic weaponry and a significant new challenge for arms controllers.
The debate over the potential for war in space is sure to heat up when Congress reconvenes later this month, and the ASAT will be its first focus. Lawmakers already have set limits on administration expenditure of funds for testing ASAT weapons, and there is growing fear that a new round in the arms race will be launched along with the ASAT.
In fact, the United States tested its first ASAT 25 years ago. The US deployed some nuclear-tipped antisatellite rockets of limited military value, but dismantled them in 1975. The Soviet Union - with some pauses while arms controllers unsuccessfully tried to address such weapons - has in recent years tested large ASAT rockets against space targets.
But Soviet tests have had mixed results. So while the Soviets may have an ASAT system that some observers consider operational, the US is closer to having a system that could be more threatening.
Arms controllers see this as a particularly opportune time to halt the ASAT competition. The Reagan administration is not so sure.
As outlined in the President's major space policy pronouncement of 1982 and in subsequent Defense Department budget requests and other statements, the ability to threaten Soviet satellites is a key part of US efforts to control the ''high ground'' of space.
Soviet leader Yuri Andropov last summer proposed a moratorium on ASAT tests. But administration officials see that as a public relations ploy to head off the F-15 test, and they are extremely wary of controlling these weapons now that Moscow actually has one that has been tested.
''The Soviets would receive a considerable unilateral advantage if the US were to refrain from testing our ASAT system after the extensive Soviet testing of the past dozen years,'' wrote Louis Nosenzo, an Arms Control and Disarmament Agency official, to an ASAT critic recently. ''It would be nearly impossible to verify through national technical means (satellites) alone the dismantling and destruction of the Soviet ASAT system.''
The Soviet ASAT weapon is carried into space by a 150-foot, SS-9 liquid-fueled rocket. The three-ton warhead maneuvers close to its target, then explodes, peppering the target with shrapnel. Of the 20 ASATs tested so far, half reportedly have failed to hit their target. And of these 20 tests, all of the more recent ones (using passive infrared homing instead of active radar that could be jammed) have failed.
The Pentagon sees this system as a potential threat nonetheless. And officials also are worried about Soviet development of ''space mines'' and lasers that could threaten US satellites. Thus they want to press ahead with testing of the F-15 ASAT as a deterrent to future Soviet advances in this area.
For more than a year now, the Air Force has quietly held ''captive carry'' tests of the F-15 system. Here, the rocket is carried aloft, but not fired.
The first firing will be to test the rocket stages. On the second ASAT flight , the ''miniature homing vehicle'' will be aimed at a star to test target acquisition. Subsequent test rockets will be aimed at satellite target balloons in space. Like many American weapons, the US ASAT warhead - a one-foot cylinder - is much smaller than the Russian version. It simply homes in on the infrared signature of the target and, using a sophisticated guidance mechanism and small course-correction rockets, rams its target at a blistering 30,000 miles an hour.
Theoretically, the US system will have several advantages over its Soviet counterpart. Whereas the Soviet SS-9 is relatively immobile and takes hours to make ready for firing, the F-15 can be moved around and quickly launched from many locations. Some observers say the US ASAT could be launched from carrier-based aircraft or submarine missiles.
The US ASAT also is closely tied to the Reagan administration's interest in an antiballistic missile defense system. ''I believe the real reason why people are so anxious to press ahead with the ASAT testing is because of the 'star wars' thrust,'' says Robert Bowman, a retired officer who once headed advanced space programs for the Air Force. ''ASAT is a necessary technological and strategic precursor'' to ballistic missile defenses.
Dr. Bowman, who is president of the Institute for Space and Security Studies, argues that the F-15/ASAT test should not be held. He notes that the Soviet Union has failed in testing its more advanced infrared homing ASAT device, but eventually could perfect it if the US does not accept Moscow's offer of a testing moratorium.
''They can do anything we can do. So why give them the opportunity to come up with a sensor that's much harder to overcome?'' he argues. ''The Soviet system has worked at all only when they've tested it with a radar sensor that gives plenty of warning that it's coming and is easily spoofed. We are in the process of modifying our low-altitude surveillance satellites with radar jamming and maneuver capability so they'll be able to counter this primitive Soviet system.''
Congress authorized $19.4 million for ASAT production for 1984. But it said that the Air Force could not test its system ''against objects in space'' unless the US is genuinely negotiating with the Soviets to control space weapons or unless the tests are necessary ''to avert clear and irrevocable harm to the national security.''