At the International Space Station had to make emergency repairs to its toilet and use an emergency urinal when the part responsible for collecting the waste malfunctioned. Well do they do with it when it gets collected?
Do they eject into outer space or back to Earth? Space Toilets separate solid from liquid waste, and the solid gets tightly bagged until it can be removed. On a space shuttle it is compressed, stored and brought back to Earth. The space station, on the other hand, deposits the solid waste onto an unmanned vehicle (known as a “Progress module”) that is eventually released toward Earth, burning up on its re-entry into the atmosphere.
Historically, space vehicles have released urine overboard. Because of the low temperatures outside, the wastewater quickly freezes into small crystals. (Apollo 9 astronaut Rusty Schweickart once described a urine dump at sunset as “the most beautiful sight in orbit.”) But urine, like just about anything else humans leave in space, can turn into orbital debris. A study conducted off the Mir space station in the mid-1990s identified “flake depressions” suspected to be caused by human waste. And even tiny objects can cause damage if they are orbiting at high velocity: In one 1983 mission, a paint flake created a crack in the space shuttle Challenger’s window, and wastewater was initially suspected as a possible cause of the 2003 Columbia disaster. In fact, the risks posed by frozen pee are limited: Orbital-debris experts say it is likely to sublimate from a solid form directly into gas within an orbit or two. In addition, waste that is released from the shuttle should be moving in the same direction as the spacecraft, limiting the possibility of a collision.
