NASA astronauts to drink their own urine

It's a water-recycling device that will process the crew's urine for communal consumption.

"We did blind taste tests of the water," said NASA's Bob Bagdigian, the system's lead engineer. "Nobody had any strong objections. Other than a faint taste of iodine, it is just as refreshing as any other kind of water."

"I've got some in my fridge," he added. "It tastes fine to me."

Delivery of the $250 million wastewater recycling gear is among the primary goals of NASA's 124th shuttle mission, which was due to launch at 7.55pm EST on Friday (0055 GMT on Saturday) from the Kennedy Space Center in Florida.

With no technical issues, NASA managers told the launch team on Friday morning to fuel the shuttle for lift-off, a three-hour operation to pump 500,000 gallons (1.9 million litres) of liquid hydrogen and liquid oxygen into the spaceship's tank for the 8.5-minute climb into orbit.

If the shuttle lifts off on time, it would arrive at the space station on Sunday so astronauts could begin 11 to 12 days of home improvements.

In addition to the water recycler, Endeavour carries two small bedrooms, the station's first refrigerator, new exercise gear, and perhaps most important for a growing crew – a second lavatory.

"With six people you really do need to have a two-bathroom house. It's a lot more convenient and a lot more efficient," said Endeavour astronaut Sandra Magnus, who will take over as a space station flight engineer from Greg Chamitoff.

Mr Chamitoff has been aboard the outpost since the last shuttle flight in June.

NASA wants to make sure the water recycling system is working well before adding another three astronauts to the station's crew.

Reusing water will become essential once NASA retires its space shuttles, which produce water as a by-product of their electrical systems. Rather than dumping the water overboard, NASA has been transferring it to the space station.

But the shuttle's days are numbered. Only 10 flights remain, including a final servicing call to the Hubble Space Telescope. NASA is preparing to end the program in 2010, after which Russian Soyuz spacecraft will be the only way to ferry crew to the space station.

"We can't be delivering water all the time for six crew," said space station flight director Ron Spencer. "Recycling is a must."

NASA expects to process about six gallons (23 litres) of water per day with the new device. The goal is to recover about 92 per cent of the water from the crew's urine and moisture in the air.

The wastewater is processed using an extensive series of purification techniques, including distillation – which is somewhat tricky in microgravity – filtration, oxidation, and ionization.

The final step is the addition of iodine to control microbial growth, Mr Bagdigian said.

The device is intended to process a full day's worth of wastewater in less than 24 hours.

"Today's drinking water was yesterday's waste," Mr Bagdigian added.