Sen. Claiborne Pell (D-R.I) sounded like a battle-scarred veteran giving the word to raw recruits the other day as he warned colleagues that President Reagan's call for a missile defense is much riskier than it sounds because of the action-reaction dynamics of the arms race.

"I remember arguing about the lack of wisdom about MIRVing," said Pell mournfully, referring to the technique of packing a number of warheads into one missile to attack a single target or hit several spaced far apart. "We're in the same situation now" in regard to space weapons, he told the Senate Foreign Relations subcommittee on arms control, which he used to chair. MIRV, the acronym for multiple independently targetable reentry vehicles, began as an effort to leapfrog the Soviets who, in turn, leapfrogged the United States.

The significant question raised at the subcommittee hearing on Thursday was whether the MIRV history will be repeated with "Star Wars" weaponry or whether the United States and the Soviet Union will find a way to halt this new race for outer space. Reagan sped up the pace by calling for an intensified effort to find an effective anti-ballistic missile (ABM) defense.

In the 1960s the Pentagon rushed ahead with MIRV in the belief it would surpass the Soviets' offensive weaponry and overwhelm their missile defense with more warheads than it could handle. Then, as now, there were scientists and politicians who tried to stem the effort.

Sen. Edward W. Brooke (R-Mass.) in 1969 led an unsuccessful Senate effort to push President Nixon into negotiating a U.S.-Soviet moratorium on MIRV flight tests.

A Pentagon spokesman at the time, John S. Foster Jr., said, "The U.S. decision to deploy the MIRV technology was based primarily upon our requirement to penetrate Soviet defenses, not upon its multiple-target capability."

The 1972 treaty limiting the defenses that Foster said MIRV was designed to penetrate did not slow up MIRV development and deployment on either side. The Soviet Union today has so many MIRVs on line that the Pentagon says they could wipe out the U.S. intercontinental ballistic missile force.

The MX missile must be deployed, the Pentagon contends, so that its MIRVs will pose more of threat to Soviet missiles buried underground in concrete and steel silos. This time around, another young Republican senator, Larry Pressler of South Dakota, is saying that the trip is not necessary. Pressler is sponsoring Senate Resolution 43 to push the president into negotiating a "verifiable" U.S.-Soviet ban "on the development, testing, production and deployment of anti-satellite weapons as a first step toward prohibiting all space-based and space-directed weaponry . . . . "

Again, one argument against such a "we won't if you won't" moratorium is that the United States had better get ahead of the Soviets with this new weaponry before they get ahead of us.

Retired Lt. Gen. Daniel O. Graham, sponsor of a non-nuclear missile defense plan, represented this argument at the Senate hearing.

"It would be a tragedy indeed for the United States to follow the Soviet lead in banning all weapons from space," Graham said.

He added that the only reason the Soviets proposed such a ban was the realization that with the space shuttle the United States could "protect the free world from Soviet nuclear attack or nuclear blackmail . . . . "

The opposite argument was given by George Rathjens, one of the scientists allied with Brooke in 1969 in trying to stop MIRV deployment.

"An agreement not to interfere with satellites would be in the interest of both the United States and the Soviet Union--more in ours than in theirs," he said.

Rathjens noted that satellites in any future war would be the eyes and ears of the American president. Destroying satellites might keep him from making or transmitting informed decisions, he added.

Sen. Charles H. Percy (R-Ill.), chairman of the Senate Foreign Relations Committee, served notice at the hearing that he would demand to know what Reagan and the Pentagon had in mind before he would go along with any kind of Star Wars weaponry for stopping missiles in space.