This year, the number of objects in orbit around Earth 4 inches (10 centimeters) or larger reached 10,000. Many smaller bits of space junk also litter space. All of them — large and small — threaten to start colliding into other bits of junk and set off a chain reaction that could make human activity in space dangerous. Everyone wishes space junk would just disappear. The January 11 shoot-down of a defunct satellite by a Chinese anti-satellite missile only highlighted the growing problem. Meanwhile, NASA is gearing up to make sure that it doesn't lose track of more desirable objects — call it space stuff — on long flights to the Moon and Mars. The agency plans to test radio-frequency identification (RFID) tags for use in space to keep track of inventory of everything from spare parts to meals. RFID tags are those ubiquitous little electronic stool pigeons than can be quizzed remotely by radio waves. They tell shops how many widgets they have sold — and whether someone is trying to walk out with a widget without paying. I'm still waiting for someone to make a wallet with an RFID tag so I can find mine more easily every morning.
Later this year, RFID tags will be placed outside of the International Space Station (ISS) and exposed to the harsh environment of space for a year to determine how hardy they are. The RFID program is just one of the experiments planned as part of the ISS Materials International Space Station Experiment.
In space, RFID tags could be used to monitor temperature and other conditions anywhere inside or outside of a ship and beam the information to a central location. RFID tags could also track spare-part inventories on long missions to Mars. Or imagine a sensor in the doorway to the ship's galley that keeps track of how many meals are consumed each day. Midnight refrigerator raids would be virtually impossible, and the crew would always be able to figure out who is eating all the good stuff.