Taking out the garbage is a mundane chore—that is, unless toting the trash involves a walk in outer space.

Every space journey since astronauts first started their extraterrestrial schlepping has created its share of refuse. Much of the unwanted material goes back to earth—NASA and other agencies try to avoid littering the cosmos if they can, but sometimes the practice is necessary. In a recent house-cleaning of the international space station, several pieces of bulky equipment had to be removed, and because of a 2010 deadline for ending all shuttle flights, there's not enough room on remaining missions to return the junk to Earth.

A few months ago, American spaceman Clayton Anderson—an avid sportsman back on his home planet—tossed a 1400-pound ammonia tank away with one mighty shove.

“I'll be sending my bill in the mail for trash disposal,” Anderson joked to Mission Control.

Earthlings shouldn't worry about the litter raining down on their heads—according to scientists, the detritus will most likely circle the earth for several months before reentering the atmosphere and burning up.