The Navy will unveil an extraterrestrial weapon 10 days from now in its battle with the Air Force over who will control military operations in space.

The Navy Space Command is scheduled to open Oct. 1 in Dahlgren, Va. The Air Force Space Command would like to gobble it up into a unified command as soon as possible, while Navy brass are fighting to stay independent, at least for the time being.

But, Vice Adm. Gordon R. Nagler disclosed recently, the Navy will be flying the only space command flag to have traveled in space.

Capt. Richard H. Truly, who will head up the Navy operation when NASA lets him go a few months from now, took the flag into space with him when he commanded the most recent space shuttle flight.

Navy officials stress that Truly didn't know he would be taking charge of the command when he carried the flag with him. He was just being a loyal Navy man, they say.

Nagler likes to rib the Air Force about not having an astronaut in charge of its Space Command (four-star Air Force Gen. James V. Hartinger is "a good lacrosse player," he says), but there are serious issues behind the competition.

The Air Force, which doesn't hold the lead position in any of the Pentagon's five unified commands, says it believes a unified command would underline the importance of space and help convince Congress to fund space operations.

Navy officials say the command would add unneeded bureaucracy and force their navigation satellites to play second fiddle to Air Force weapons programs. "The Navy depends on space more than any other service, day to day," Nagler said.

The issue is still being debated in the offices of the Joint Chiefs of Staff.

Navy and Air Force brass express optimism that the decision--ultimately by Secretary Caspar W. Weinberger and possibly President Reagan--will go their way.***

OPTIONS ON AIRCRAFT . . . Navy Secretary John F. Lehman Jr. has created a "blue-ribbon oversight committee on strike aircraft" after Deputy Secretary Paul Thayer ordered him to go slow on his plans to produce an upgraded A6 bomber.

In an Aug. 31 memo Lehman said the panel would solicit industry views on a new or improved attack aircraft. Thayer suggested upgrading the F18 into a two-seater jet for the Marines or developing a new, all-weather attack plane. Lehman appointed Melvyn R. Paisley, assistant secretary of the Navy for research, engineering and systems, and Adm. Ronald J. Hays, vice chief of naval operations, to head the committee. They will report by Dec. 1 to Lehman; Lehman is to report to Thayer early next year.***

RETIREMENT PAY . . . The Pentagon is approaching a moment of truth again on the much-criticized military retirement system. An internal study is nearing completion, and outside critics--notably Rep. Les Aspin (D-Wis.)--warn that it better come up with more than applause for the way things are now.

Numerous critics, including the President's Private Sector Survey on Cost Control (known as the Grace Commission), have said military pensions are far too generous and should be brought into line with civilian pensions. Pentagon officers have mounted an intense campaign to present an opposing view. "It is important to emphasize that the military retirement system is not an old-age pension plan . . . " Lawrence J. Korb, assistant secretary of defense for manpower, reserve affairs and logistics, testified recently. "Rather, it is intended to help shape a professional, ready force . . . . "

But Korb reportedly has urged the services to keep an open mind about proposed revisions, because Congress will attack the retirement system if the Pentagon does not. Aspin has said his House Armed Services subcommittee on military personnel and compensation will wait to act until the Pentagon's Quadrennial Review of Military Compensation, once promised for October, makes its report late this year.

But Aspin warned that if the review does not recommend substantive changes Congress will. He suggested that an amendment forcing soldiers to contribute 7 percent of their pay to a retirement plan probably could pass the House today.