NASA is keeping a close eye on two pieces of space junk expected to whiz by the International Space Station in back-to-back passes, and the station may even have to dodge the orbital debris.
The drifting space flotsam includes the remains of a Russian Cosmos satellite and a leftover chunk of an old Indian rocket. The Russian satellite debris will creep close to the space station on Thursday morning (Sept. 27), with the Indian rocket remnant zooming by on Friday, NASA officials told SPACE.com.
As a precaution, NASA and its Russian partners began planning for a possible "debris avoidance maneuver" on Thursday morning that would steer the station clear of both pieces of space debris. The maneuver, if ultimately required, would fire the thrusters on a European cargo ship currently docked at the station for just over two minutes to move the station clear of the space junk.
NASA and its partners traditionally order a debris avoidance maneuver when a piece of space junk is expected to pass so close that it enters a safety perimeter shaped like a pizza box that extends just over 15 miles (25 kilometers) around the space station, and a half-mile (0.75 km) above and below the orbiting lab. [Space Junk Photos & Cleanup Concepts]
NASA spokesman Rob Navias of the Johnson Space Center, home to the agency's space station Mission Control center, told SPACE.com the two space debris fragments being tracked now will come just inside that safety zone.
Navias said the avoidance maneuver would be performed at 8:12 a.m. EDT (1218 GMT) on Thursday, if ultimately required. It is possible that additional tracking of the space junk may allow station flight controllers to call off the maneuver, he added.
The Russian satellite debris will make its closest approach to the space station on Thursday at 10:42 a.m. EDT (1432 GMT), with the Indian rocket debris passing by on Friday at 1:47 a.m. EDT (0547 GMT), he added.
At no time will the station's three-person Expedition 33 crew be in danger, NASA officials said. The station is currently home to NASA astronaut Sunita Williams, Japanese astronaut Akihiko Hoshide and Russian cosmonaut Yuri Malenchenko.
Space junk has been a growing threat for astronauts living on the International Space Station, as well as other satellites in orbit. NASA and the U.S. military's Space Surveillance Network track about 20,000 pieces of space debris in orbit today.
The potential for Thursday's space debris avoidance maneuvers has forced station flight controllers to delay the departure of the European cargo ship that will perform the engine burn — the Automated Transfer Vehicle 3 (ATV-3) — by at least one day. The unmanned spacecraft was originally scheduled to leave the space station on Wednesday (Sept. 25), but a minor computer glitch delayed its undocking.
The next chance for the ATV-3 spacecraft to undock will be Friday afternoon, Navias said.
This story was provided by SPACE.com, a sister site to LiveScience. You can follow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik. Follow SPACE.com @Spacedotcom. We're also on Facebook & Google+.