One of the most important pieces of space history has been misplaced in NASA's archives.

The government has misplaced the original recording of the first moon landing, including astronaut Neil Armstrong's famous "one small step for man, one giant leap for mankind," a NASA spokesman said yesterday.

Armstrong's moon walk, seen by millions of television viewers on July 20, 1969, is among the transmissions that NASA has failed to turn up in a year of searching, spokesman Grey Hautaloma said.

"We haven't seen them for quite a while. We've been looking for over a year, and they haven't turned up," Hautaloma said.

The tapes also contain data about the health of the astronauts and the condition of the spacecraft. In all, about 700 boxes of transmissions from the Apollo lunar missions are missing, he said.

"I wouldn't say we're worried -- we've got all the data. Everything on the tapes we have in one form or another," Hautaloma said.

NASA has retained copies of the TV broadcasts and offers several clips on its Web site. But those images are of lower quality than the originals stored on the missing magnetic tapes.

Because NASA's equipment was not compatible with the TV technology of the day, the original transmissions had to be displayed on a monitor and reshot by a TV camera for broadcast.

Hautaloma said it is possible the tapes will be unplayable if they are found because they have degraded significantly over the years -- a problem common to magnetic tape and other recordable media.

This will be a tragic loss if the materials are lost or damaged beyond recovery.