Thisstory was updated at 12:20 p.m. EDT.
The spaceshuttle Discovery dodged a mysterious piece of orbital trash Thursday as its astronautcrew prepared for a planned landing in Florida.
Shuttlecommander Rick Sturckow and pilot Kevin Ford fired Discovery?s engines at 12:02p.m. EDT (1605 GMT) for 14 seconds to move the spacecraft clear of the spacejunk and continue on with their landing attempt today.
The?mystery orbital debris,? as Mission Control called it, apparently came freefrom the shuttle or the International Space Station while both vehicles werelinked during a spacewalk on Saturday. NASA engineers do not know what theobject is or its size, but it has been creeping ever closer to Discovery sincethe shuttle fired its engines to leave the station?s orbital neighborhoodTuesday.
At 12:55p.m. EDT (1655 GMT), the debris was expected to fly within a safety perimeterbox that extends out 25 miles (40 km) around Discovery and 2 miles (3 km) aboveand below the shuttle.
?Based onthe latest tracking data, the object will move in and out of that box over thecourse of 11 consecutive orbits,? said NASA commentator Pat Ryan. ?The twoobjects [are] in essentially the same orbit, but with different velocities.?
Discovery?sdebris-dodging maneuver will not impact NASA?s plan to try and landthe shuttle at the Kennedy Space Center in Florida today, Mission Controlsaid. The shuttle is due to touch down at 7:05 p.m. EDT (2305 GMT), but couldalso try for an 8:42 p.m. EDT (0042 Sept. 11 GMT) opportunity depending onweather conditions.
Thunderstormsnear the shuttle runway could keep Discovery and its seven-astronaut crew in orbitan extra day. NASA could also activate a backup runway in California as earlyas Friday in order to bring the shuttle home. The shuttle blastedoff late Aug. 28.
Spacedebris has dogged Discovery?s mission to the International Space Station.
A piece ofChinese satellite debris was due to pass by the space station twice earlyWednesday, but never came anywhere near the orbiting laboratory. Last week, amassive chunk of a 3-year-old European rocket buzzed the orbital outpost andlinked shuttle, zipping past about 1.3 miles (3 km) ahead of the station, butit too posed zero risk of impact, Mission Control said.
Discoveryis returning to Earth to wrap up a 13-day cargo run to the space station. Theastronauts performed three spacewalks, replaced one member of the station?screw and delivered tons of supplies, science gear and a treadmill named after TVcomedian Stephen Colbert.
The shuttleis bringing home NASA astronaut Tim Kopra, who is ending a nearly two-monthmission to the space station. He was replaced by astronaut Nicole Stott duringDiscovery?s flight.
Discoveryis also returningBuzz Lightyear, a 12-inch Disney toy, to Earth to wrap up his own 15-monthspace mission. Buzz launched to the station in May 2008 as part of an educationalcampaign and will receive a hero?s welcome at Walt Disney World in Florida -including a tickertape parade - after returning to Earth.
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SPACE.comis providing complete coverage of Discovery's STS-128 mission to theInternational Space Station with Managing Editor Tariq Malik and Staff Writer ClaraMoskowitz in New York. Click herefor shuttle mission updates and a link to NASA TV.