A spacewalking astronaut tossed two large chunks of junk off the international space station Monday, hurling the old equipment weighing more than half a ton into orbit, AP reported. The outdated ammonia tank and camera mounting joined more than 9,000 pieces of orbital debris already being tracked from Earth. «I'll be sending my bill in the mail for trash disposal,» Clayton Anderson joked to Mission Control. NASA normally tries to avoid adding to the orbiting junkyard, but officials felt they had no choice in this case. The equipment had to be removed, and because of a 2010 deadline for ending all shuttle flights, NASA does not have room on its remaining missions to return the tank to Earth. Anderson hurled the 1,400-pound (635-kilogram), refrigerator-size ammonia tank away from the station with a single strong shove. His first toss was a 200-pound (90.7-kilogram) camera mounting. For each celestial toss, Anderson leaned back on the end of the space station's 58-foot (17.6-meter) robot arm, as far from the space station as possible, then rocked forward and shouted «Jettison!» as he shoved. The tank had been launched in 2001 to provide spare coolant in case of a leak at the orbiting complex. The surplus ammonia was never needed, and its tank had exceeded its life expectancy. Flight controllers expect the tank to circle Earth for 10 or 11 months before re-entering the atmosphere and burning up. There should be no danger of a collision between the tank and station before that happens, officials said. Small chunks are likely to survive next year's fall through the atmosphere; NASA officials hope those pieces will hit the ocean. The camera mounting should burn up entirely because of its smaller size. Russian cosmonaut Fyodor Yurchikhin joined Anderson outside the station, where he replaced a bad circuit breaker and cleaned a docking port. The spacewalk lasted 7 1/2 hours, an hour longer than planned, allowing the two to complete some extra chores.
