Sunday, June 01, 2008

Toilet to Tang - Space Station and Earth Have Limited Water Supply

Space shuttle Discovery launched from Cape Canaveral today and will dock with the International Space Station (ISS) on Monday. Discovery is bringing Hope and relief. And none too soon.

The Japanese made Kibo (Hope) lab is the size of a school bus and is the largest section of the ISS to date. The plan is for Kibo to allow experiments that last several months to be conducted, rather than the days to weeks allowed now. Kibo will increase the number of experiments which will eventually hold ten racks of equipment.

The relief is the delivery of the toilet vacuum pump to replace the solid waste pump that broke while in use and the replacement that barely works. For days, the three occupants have had to manually flush the toilet with extra water several times a day, a time-consuming, water-wasting job. The whole waste elimination thing is quite complex compared to the Earth bound process. The equipment designed into the ISS by Russia and installed 7 years ago on the ISS is similar to that of the space shuttles. Until the spare parts arrive on Monday, the cosmonauts will have to use baggies or the Soyuz head which has limited capacity.

Since there is no gravity to either hold a toilet bowl full of water in place or pull human wastes down, designing a toilet for zero-gravity was not an easy task. NASA had to develop a way to use air flow to make the urine or feces go where they wanted.

There is a toilet on each space shuttle which can be used by men or women. Although it is designed to be as much as possible like those on Earth, there are a number of changes. Straps are in place to hold feet against the floor. Pivoting bars swing across the thighs, ensuring the user remains seated. Since the system operates on a vacuum, a tight seal is essential.

Besides the main toilet bowl, there is a hose, which is utilized as a urinal by men and women. It can be used in a standing position or can be attached to the commode by a pivoting mounting bracket for use in a sitting position. A separate receptacle allows for disposal of wipes. All three units use flowing air instead of water to move waste through the system.

The human waste is separated and solid wastes are compressed and stored on-board, and then removed after landing. Waste water is vented to space, although future systems may recycle it. The air is filtered to remove odor and bacteria and then returned to the cabin.

Hopefully, there is sufficient reading material aboard for the task.
Discovery is also bringing water which, as noted, is necessarily being wasted on waste. Right now, there is no water recovery/recycling system aboard. NASA recently unveiled a $250mil urine recycling system that is scheduled for ISS installation this fall before the station crew doubles next year.

The Waste Recovery System is the second part of the station's Regenerative Environmental Control and Life Support System, NASA said. The first part, the Oxygen Generation System, went up last year. The WRS will distill waste, remove solid particles such as lint or hair, and then take the water through a series of filtration beds followed by a high-temperature catalytic reaction to remove any other contaminants and micro-organisms.

The result, officials said, will be cleaner than tap water, officials said. Faint praise, perhaps, but NASA's biggest concern isn't the quality of the water as much as the psychological barrier posed by the water's source.
Much of what happens in space does not stay in space. The waste water recycling system is also being tried here on the ground. Here in Orange County, California, waste water has been purified and pumped into the aquifer since 1976 with no ill effects. A new plant is on line pumping recycled water into the drinking water supply.

The finished product, which district managers say exceeds drinking water standards, will not flow directly into kitchen and bathroom taps; state regulations forbid that.

Instead it will be injected underground, with half of it helping to form a barrier against seawater intruding on groundwater sources and the other half gradually filtering into aquifers that supply 2.3 million people, about three-quarters of the county. The recycling project will produce much more potable water and at a higher quality than did the mid-1970s-era plant it replaces.
A nice cold glass of Tang, anyone?

The life of Indigo Red is full of adventure. Tune in next time for the Further Adventures of Indigo Red.


Marie's Two Cents said...

Makes you wonder what kind of space junk is floating around up there lol

I LOVE watching the Space Shuttle take off and land.

It never get's old to me :-)

Indigo Red said...

Strategic Air Command is tasked with tracking everything in orbit from satelites to a space glove. What I think is amazing is that, so far, none of the debris has hit the station or shuttles ... yet.

The launches still inspire awe.

Mike's America said...

Thanks for that riveting expose on toilets in space. It raised only one question that propriety prevents me from asking.

Indigo Red said...

Propriety? We don't need no stinking propriety!

So go ahead, Mike, shoot.

Gayle said...

I wonder what Mike's question was?

Even going to the bathroom out there is an adventure! I'll be thinking about this for awhile now every time I flush. :)