NASA needs parts no one makes anymore.

So to keep the shuttles flying, the space agency has begun trolling the Internet -- including Yahoo and eBay -- to find replacement parts for electronic gear that would strike a home computer user as primitive.

Officials say the agency recently bought a load of outdated medical equipment so it could scavenge Intel 8086 chips -- a variant of those chips powered I.B.M.'s first personal computer, in 1981.

When the first shuttle roared into space that year, the 8086 played a critical role, at the heart of diagnostic equipment that made sure the shuttle's twin booster rockets were safe for blastoff.

Today, more than two decades later, booster testing still uses 8086 chips, which are increasingly scarce. NASA plans to create a $20 million automated checking system, with all new hardware and software. In the meantime, it is hoarding 8086's so that a failed one does not ground the nation's fleet of aging spaceships.