The Space Shuttle Is Delivering a New Toilet to the Space Station
Saturday, November 15, 2008
The grand drama of humankind's conquest of space has featured as a recurring subplot the mystery of how people in zero gravity can possibly go to the bathroom. The latest twist in that narrative is about to take place high above Earth, where astronauts will deliver to the international space station a new toilet, officially known as the waste and hygiene compartment, plus a contraption that can recycle urine into drinkable water.
These and other upgrades were carried into orbit last night by the space shuttle Endeavour, carrying a crew of seven.
The new toilet will go into the American laboratory known as Destiny. The only toilet currently on the station is in the Russian lab. The second toilet, the wastewater recycling system, new sleeping quarters and a refrigerator are all part of what NASA is billing as "extreme home improvements" on the space station. The goal is to make the station habitable by as many as six astronauts at a time, double the current crew limit.
Human sweat, excess water from tooth brushing, and water extracted from the humid spaceship interior have long been reprocessed into something astronauts can consume. But urine has gone to waste, tossed overboard (or vented, as NASA puts it), an egregious inefficiency in the great desert of space.
The new water recovery system, housed in two racks the size of refrigerators, will save 743 gallons of water a year that would otherwise have to be launched into orbit at great expense. This will also help NASA plan for future missions to the moon, where astronauts might operate for prolonged periods with little chance of seeing a water delivery truck anytime soon.
Standing between the urine and the consumable end product are muscular apparatus that distill, filter, heat and chemically transmogrify the liquid. The instruments include a catalytic reactor, a gas separator, multi-filtration beds, a particulate filter, a reactor health sensor, a microbial check valve, a fluids control and pump assembly, and a pressure control and purge assembly. This removes almost all the organic molecules from the liquid.
"It's safer than what you normally drink out of the tap," said David Hand, an engineering professor at Michigan Technological University who helped develop the water recovery system.
"I've sipped the water. It tastes like water," said Jennifer Morcone, a NASA spokesman. Still, she said, NASA understands that, even with the strong assurances of purity from engineers, astronauts might recoil from the urine-to-water alchemy. But in taste tests, the recycled urine passed muster.
"The one thing people note is a hint of iodine, a medicinal taste," Morcone said. The iodine is used for microbial control. "As soon as the cap comes off and it breathes for a minute, it doesn't smell like much at all," she said.
The water created from the new recycling process will be brought back to Earth for testing before any astronauts get to drink it.