The space agency insisted yesterday that the maiden flight of space shuttle Columbia will take place in March as scheduled even though technicians at Cape Canaveral will have to work around the clock for the next five months to accomplish it.

"We're using a March 10 launch date as our internal guideline," the shuttle orbiter program manager, Aaron Cohen, said at a news briefing at Johnson Space Center in Houston. "Either way, those dates look very feasible."

Cohen said 1,286 ceramic tiles remain to be fastened to the fuselage of the space shuttle before it can be moved into the Vehicle Assembly Building. tAt the rate the tiles were being fastened last week and early this week, all 30,922 tiles should be in place on the fuselage in less than three weeks.

Cohen said plans call for the Columbia to be moved out of the Orbiter Processing Facility and into the assembly building on Nov. 23. Two days later, he said, the huge external tank that will hold hydrogen fuel for the shuttle's main liquid-fueled engines will be fixed to the orbiter and a day after that the two solid-fueled auxiliary engines that will help carry the shuttle into orbit will be mated to the orbiter.

Then an exhaustive five-week testing program will begin. After that, the orbiter, its giant fuel tank and two solid-fuel rocket engines will be wheeled to the launch pad for six weeks of tests concluding Feb. 7 in a 20-second test-firing of the shuttle's liquid-fuel engines.

All of this must be accomplished without any serious failure delay to meet a March launch date. Kennedy Space Center spokesman Hugh Harris acknowledged yesterday that technicians will be working three shifts a day seven days a week to achieve that.

"We're working around the clock at present," Harris said, "and we expect we'll be working around the clock through the next few months."