The rush is on to fix the flush in space.

That's because three astronauts are orbiting the Earth in the International Space Station with a balky toilet.

So folks on the ground in Florida are putting together a repair kit to send up Saturday when seven astronauts blast off to the space station to deliver a large module, part the Japanese space laboratory "Kibo."

The pump astronauts plan to replace isn't something you can get at the local home repair store.

So tucked away in a diplomatic pouch from Russia and shepherded by a NASA worker, a 29-pound toilet pump was winging its way Wednesday toward the Kennedy Space Center, where technicians will put it aboard the space shuttle Discovery as a last-minute addition.

If all goes well, astronauts will install a new gas liquid separator pump, part of the system that processes urine from three astronauts.

The toilet for solid waste is working OK, said NASA headquarters spokesman John Yembrick, and the astronauts can use a toilet on a Russian space ship attached to the space station or store the urine in waste collection bags

"Clearly, having a working toilet is a priority for us," NASA payload manager Scott Higginbotham said during a morning briefing at the Kennedy Space Center.