President Reagan sharply criticized yesterday efforts by House Armed Services Committee Chairman Les Aspin (D-Wis.) and Rep. George E. Brown Jr. (D-Calif.) to persuade Congress "to junk" the Air Force's controversial, nine-year-old, $5 billion antisatellite (ASAT) program.

In an unusually open, public relations battle, White House officials in Santa Barbara distributed a statement attacking a Wednesday press release by the two legislators that said "the current ASAT. . . has simply failed to fulfill its technical promise." Aspin and Brown said killing the program would save $324 million in fiscal 1987 and $2.7 billion overall.

The president, according to White House spokesman Larry Speakes, "has expressed deep concern" that the two congressmen want to kill the ASAT program, which Reagan said "the United States now has nearing deployment."

Aspin and Brown noted that the program has slipped five years behind schedule, primarily because of technical problems. However they admitted that a year of the slippage came from a congressional test ban. Speakes argued that "many of the problems in the program, as Congress knows, are due to Congress' own prohibition against testing and other congressional program adjustments."

However, the two legislators pointed out that the Air Force decided last month to "restructure" the program. The service sharply cut purchase of ASAT missiles from 112 to 35 and decided to limit deployment of the weapons to Langley Air Force Base, Va., eliminating plans to station some at McChord Air Force Base, Wash.

Aspin and Brown said the Air Force cutback would provide "too few missiles to engage all the targets the Air Force told us in 1983 it needed to engage." The Speakes release praised the ASAT program as "a key, effective element of our deterrence." If war occurred, Speakes said, "our ASAT program would be critical to deny any adversary the use of space-based systems. . . . "

Aspin and Brown added that more effective approaches to ASAT, such as ground-based lasers, are being funded in the president's Strategic Defense Initiative, the "Star Wars" program. They said the best approach, however, was for a "bilateral and verifiable arms-control agreement that would keep the Soviets from acquiring a modern and effective ASAT capability of their own."

The White House statement said "unilateral actions," such as killing the ASAT program, "undermine the position of our negotiators in Geneva and make it substantially more difficult, if not impossible, to reach a verifiable and equitable agreement with the Soviets."

Responding to the administration, Aspin and Brown said yesterday they were "surprised to hear the White House calling it more difficult" to get an agreement on ASATs with the Soviets. They said the administration had said several times that it would not enter into negotiations on ASATs on grounds that such a pact could not be verified and thus "was not in our national-security interest."

The Soviets have a 10-year-old ASAT system that most U.S. experts consider rudimentary. In 1983, then-Soviet leader Yuri Andropov said Moscow's system, that had failed in several flights, would not be tested again as long as the United States refrained from testing a system.

Last September, in the third of 12 development tests, the U.S. system hit a a target satellite in space. Thereafter, Congress voted to prevent the Pentagon from testing the system against another target in space as long as the Soviets continued their three-year moratorium.

Before the congressional test ban was approved, the Air Force launched two targets, costing $20 million, for future ASAT tests. In December, Pentagon officials said they would obey the law but continue the weapon development program, testing the system against points in space rather than targets.

The U.S. antisatellite weapon is carried aloft by an F15 fighter plane and launched in the direction of the target. A homing device guides the weapon into the path of the satellite, destroying it on impact.

The older Soviet ASAT is placed on a rocket launched from the ground and goes into an orbit similar to its target. Radar guides the weapon after several orbits close to the target, and the weapon explodes, destroying both objects.

The United States has designed defenses against the Soviet system and started building them on newer U.S. satellites. Critics of the U.S. weapon say newer Soviet satellites will be able to maneuver out of the path of the F15 system.