Cutting edge trash dryer to take care of rotten space waste

Washington, Nov 19 : A team of scientists is developing a cutting-edge trash dryer for NASA, which would take care of rotten and smelly space waste.

NASA will need a new solid waste strategy before it sends astronauts on extended missions to Mars or an outpost on the moon.

In space, waste can't simply be "thrown out."

In the cramped living quarters of a space station, garbage can pile up, spoil and become a health hazard for astronauts.

If astronauts place it outside the airlock, it will orbit alongside their spacecraft. If they eject it away from the spacecraft, they might encounter it again later. Or, even worse, it could contaminate another planet.

According to a report in Chronicle Online, that has prompted Jean Hunter, associate professor of agricultural and biological engineering, to work with research partner Orbital Technologies Corp. (ORBITEC) of Madison, Wisconsin, to develop a cutting-edge trash dryer for NASA.

"We don't know if there's life on Mars, but we know that our trash is teeming with it," said Hunter.

Hunter's group has developed a system that blows hot, dry air through wet trash and then collects water from the warm, moist air that emerges.

This water can be purified for drinking, and the remaining trash is dry, odorless and inert. The air and the heat are both recycled to contain odors and save energy.

Jean Hunter's team is also working on recovering potable water from space wastewater.

On the planned lunar outpost, urine and hygiene water will have to be recycled. Existing NASA technology can recover around 85 percent of that water, but the last 15 percent, charitably called "brine," poses a much greater challenge.

Hunter's team has a grant with ORBITEC to develop a new specialized brine dryer, but the team has submitted another proposal to dry brine in the trash dryer.

Heat-pump dehumidification drying, as the technique is called, which has commonly been used for drying lumber, needs to be adapted for space, though, because existing systems depend on the Earth's gravity and contain materials unacceptable for spaceflight.

Hunter's team has been testing the dryer with fake "space trash" - a mix of paper towels, duct tape, baby wipes and dog food, to simulate the astronauts' food scraps.

A prototype heat-pump dryer is currently being tested at the NASA Ames Research Center.

ORBITEC may also make a prototype that performs under zero gravity, is small and light enough for a spacecraft and can survive the rigors of a rocket launch.

ANI