President Reagan, seeking a "calm and deliberate assessment of the facts" about the space shuttle explosion, appointed a 12-member commission yesterday to take over the investigation from the National Aeronautics and Space Administration.

Former secretary of state William P. Rogers was named chairman, and Neil A. Armstrong, commander of the first manned lunar landing and first man on the moon, is vice chairman. Other members included astronaut Sally K. Ride and test pilot Charles (Chuck) Yeager.

White House spokesman Larry Speakes said an outside investigation was ordered to ensure that it would be done by people "with no axe to grind."

The panel, many of whose members have close ties to the space program, was instructed to report in 120 days. Reagan limited its mandate to reporting the cause of the accident and ways to prevent a recurrence, and Speakes said the group will not examine the space program's future.

Acting NASA administrator William Graham said shuttle launches will be suspended until the report is complete.

Speaking to reporters here after the commission was announced, he said that the shuttle is an "operational system" that has "proven itself" in 24 flights and that "the fundamental concept and operation of the system appears to us to be sound" despite the explosion that killed seven astronauts a week ago today.

"We don't look like we're going to have to go back to the design process again and envision reconfiguring the system or making a very major fundamental design change. What we're looking at here is a question of making sure the difficulty that occurred is corrected . . . and will never occur again," he said.

[Tributes to the Challenger astronauts yesterday included a private mass in Concord, N.H., for Christa McAuliffe; a memorial service at the Akron, Ohio, high school where Judith A. Resnik was valedictorian, and an observance in Lake City, S.C., for Ronald E. McNair, according to news services.]

The commission, to which as many as eight others may be named, replaces an interim board created by NASA last week.

Rogers said the group will rely on NASA for information but can also seek it elsewhere.

In announcing the panel, Reagan said that "the crew of the Challenger took the risks and paid the ultimate price because they believed in the space program . . . .

"We owe it to them to conduct this investigation so that future space travelers can approach the conquest of space with confidence, and America can go forward with enthusiasm and optimism, which has sparked and marked all of our great undertakings."

White House officials had considered allowing NASA to appoint a permanent investigative board, as the agency did after the 1967 Apollo launch-pad fire that killed three astronauts. But Reagan decided Friday, after returning from a memorial service in Houston, to appoint a commission.

Speakes told reporters, "Think what type of questions you would have been asking in this room had NASA appointed the permanent and only board."

Panel members named yesterday:

Rogers, who served as secretary of state from 1969 to 1973 and attorney general from 1957 to 1961 and is a partner in the New York law firm of Rogers & Wells.

Armstrong, spacecraft commander for Apollo 11 and chairman of Computing Technologies for Aviation Inc. of Charlottesville, Va.

Yeager, a retired Air Force brigadier general, former test pilot of experimental aircraft, first man to penetrate the sound barrier, the first to fly at a speed of more than 1,600 mph and an aerospace consultant.

Ride, a mission specialist on the June 1983 voyage of Challenger, first American woman in space and training as a mission specialist.

Dr. Albert D. (Bud) Wheelon, physicist, senior vice president and group president of the space and communications group at Hughes Aircraft Co.

Robert W. Rummel, aerospace engineer, former vice president of TWA Inc. and now president of Robert W. Rummel Associates of Mesa, Ariz.

Dr. Arthur B.C. Walker Jr., professor of applied physics, Stanford University.

Richard P. Feynman, physicist and professor of theoretical physics, California Institute of Technology.

Eugene E. Covert, educator, engineer, professor of aeronautics at Massachusetts Institute of Technology and a consultant to NASA on rocket engines.

Robert B. Hotz, editor and publisher; editor of Aviation Week & Space Technology from 1953 to 1980 and, since 1982, a member of the General Advisory Committee to the Arms Control and Disarmament Agency.

David C. Acheson, senior vice president and general counsel of Communications Satellite Corp. from 1967 to 1974 and now a partner in the Washington law firm of Drinker, Biddle & Reath.

Maj. Gen. Donald J. Kutyna, Air Force director of space systems and command, control and communications and manager of the Defense Department space shuttle program from 1982 to 1984.