WATERTON, COLO., NOV. 24 -- President Reagan celebrated recent scientific advances in his antimissile Strategic Defense Initiative program today and vowed "it will not be traded away" in forthcoming talks on reducing strategic weapons with Soviet leader Mikhail Gorbachev.

Reagan did not explicitly rule out a possible delay in future deployment of the space-based missile defense system as part of an agreement with Gorbachev on reducing strategic arms.

However, Reagan sprinkled a speech to Martin Marietta Corp. workers here with promises that the project would not be stopped by the Soviets. "You're not working to build a bargaining chip," he said to enthusiastic applause. "It will not be traded away."

The president repeatedly criticized Soviet and congressional attempts to limit the missile shield program. "Let there be no doubt, giving up the Strategic Defense Initiative and the protection it will provide is too high a price for any agreement" with Gorbachev, he said. While the Soviets are waging a "propaganda campaign" against SDI, Reagan said, "We must not be lulled into reducing our commitment."

Responding to congressional budget cuts in the program, he said, "America cannot afford not to do everything necessary to develop this missile defense system and put it into operation."

Reagan received a classified briefing here on the "Zenith Star" project, a feasibility study being conducted by Martin Marietta Astronautics to come up with a "road map" for a space-based laser experiment. The tour and the president's subsequent address are part of a White House effort to influence public opinion before the Gorbachev summit Dec. 8-10 in Washington.

Today, Reagan reiterated his contention that the missile defense program would succeed in protecting against nuclear attack, but he did not repeat earlier, more ambitious claims that SDI would make ballistic missiles obsolete. "SDI is not a weapon of war, but an insurer, a protector of the peace," he said.

Navy Capt. John Dewey, a spokesman for the Pentagon's Strategic Defense Initiative Organization, said today that the Zenith Star tests are currently being developed to remain within the restrictive interpretation of the 1972 Antiballistic Missile (ABM) Treaty. Congress has insisted that the administration honor this interpretation, at least for the time being, although Reagan has asserted that a broader interpretation of the treaty is legally correct. Dewey said the tests could be altered later -- and done at less expense under the broader interpretation -- if so decided by the president.

Reagan today renewed his charge that the Soviets have violated the ABM treaty by constructing the Krasnoyarsk radar. As for the U.S. program, commonly called "Star Wars," he said only, "It is totally within the limits of the ABM treaty."

In remarks just before Reagan's address, Frederick Seitz, president emeritus of Rockefeller University, severely criticized any restrictions on SDI testing. "Early in the 1990s," Seitz said, "the Soviets should have it all together, ready to break out of the treaty if and when they wish. It will be their gain."

Restrictions on the U.S. program "are the death knell of SDI," he added, and "could deliver us into the hands of the potential enemy."

For all his rhetoric insisting that the program will not be stopped, Reagan has not ruled out the possibility of delaying deployment as part of a deal for deep cuts in strategic arsenals. Asked today if he would be willing to accept such a delay by agreeing to a longer period of compliance with the ABM treaty, Reagan responded:

"I'm not going to discuss that right now about SDI. But as I've said before, I'll just answer it with this: SDI is not a bargaining chip."

Reagan stopped here en route to a Thanksgiving vacation at his ranch near Santa Barbara, Calif., where he will be preparing for the summit. In addition to briefing papers, Reagan will be screening a 20-minute film on Gorbachev's policies put together by the National Security Council, according to White House spokesman Marlin Fitzwater.

The spokesman said Reagan has spent more time with Gorbachev "than any other world leader." Fitzwater added, "Certainly nobody in Washington knows Gorbachev as well as the president."