As for peeing, each astronaut is given his or her own funnel — made in different shapes for men and women — which attaches to a hose on the toilet. But as gravity diminishes in space, ego apparently doesn't.
"They had three different sizes of funnels and the guys were always choosing the largest size," Roberts said of the astronauts in the shuttle program.
In 1986, the Soviet Union built the Mir space station, which had a bathroom with a toilet that vented the waste out into space. By the time space officials were retiring Mir in 2001, the space station's solar panels had lost about 40 percent of their effectiveness, Roberts said.
"They realized that a large part of the damage to these solar panels was frozen urine floating in space at very high speeds," Roberts told his audience.
Today on the International Space Station, a $100 billion orbiting outpost that has been staffed with rotating crews since 2000, urine gets recycled into drinking water through a filtration system.
Fecal matter, meanwhile, often gets packed up and cast off from the space station with other trash in capsules that burn up in the atmosphere, Roberts said. But with longer missions, like flights to Mars, some researchers are thinking about how to recycle feces, too. For example, some scientists propose that human waste could line the walls of future spacecraft to act like a radiation shield, protecting astronauts from the harmful effects of cosmic rays.
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