“The beautiful trail in the sky looked like a mysterious celestial event,” says space.com. Actually, it was Discovery emptying their toilet before returning to Earth. 150 lbs of waste water collected over 10 days was dumped, creating an arc shaped glowing trail. According to astronauts, waste water freezes into a cloud of thin ice droplets upon ejection. In May, astronauts made a toast to the space station’s new urine/water recycling system by drinking their recycled piss. The water recycling system cost about $250 million and will be used daily to recycle urine and wastewater back into potable water suitable for drinking, food preparation, bathing and oxygen generation.