The Defense Department is planning to establish a government-funded think tank to support the Strategic Defense Initiative (SDI), its $3 billion-a-year effort to develop a space-based defense against nuclear missiles, officials said this week.

Lt. Gen. James A. Abrahamson, chief of the SDI office, has won Defense Secretary Caspar W. Weinberger's support for a "Star Wars" version of the Rand Corp., a Pentagon spokesman said in response to inquiries.

The center -- "essentially a government-owned, high-technology company doing systems analysis," as one industry source said -- would be based in the Washington area and might cost $30 million per year or more, officials said.

The proposal has drawn strong opposition from some persons in industry, who say the proposed think tank would compete unfairly with private firms while being almost immune from congressional scrutiny.

Other opponents portrayed the effort as a means to help entrench the controversial SDI program while the Reagan administration remains in power.

"There are some high emotions on it," one industry consultant said.

Abrahamson's spokesman declined to discuss the proposal, but the Air Force general has told others that a nonprofit think tank could offer impartial advice. Private firms may be biased when evaluating programs that could yield large profits in the future, officials said.

Robert B. Sims, chief Defense Department spokesman, said Weinberger believes the new think tank would help "insure over the long run that we make good choices and that we have technical support that would hold no allegiance to any particular sector or organization."

"He has been briefed on the concept, and thinks it's a good idea," Sims added. "He has not signed off on any paperwork yet. It is in the works, as far as ironing out the various details of the paperwork."

Military and civilian science agencies support 36 federally funded research and development centers (FFRDCs, as the bureaucracy calls them).

The centers and laboratories, many managed by private firms or universities, receive more than $5 billion in sole-source, noncompetitive contracts each year, according to the Professional Services Council, a trade association.

The Defense Department sponsors nine centers, including Rand's Project Air Force in California and the equivalent Center for Naval Analyses in Alexandria; the Logistics Management Institute in Bethesda, and the recently formed Software Engineering Institute in Pennsylvania, which studies military applications of computer programs.

A new think tank dedicated to SDI research would expand the program without as much red tape as expanding the SDI organization or letting more competitive contracts would entail, industry officials said.

"Obviously, Abe Gen. Abrahamson has got to be motivated by a desire to institutionalize the program, and this may be one of the ways to do that," one industry source said.

The ease of dealing with such centers has prompted many agencies to use them when private firms could do the work for less money, said Virginia Littlejohn, executive director of the Professional Services Council, which represents private firms that compete with federally supported think tanks.

"These FFRDCs tend to be among the highest priced -- if not the highest priced -- of the independent and high-quality research firms," Littlejohn said.

"We have been watching with increasing concern the degree to which they are expanding their mandates. There is no real sunset provision, there is no real oversight. So they just continue," she said.