Satellite Debris No Threat to Space Station, Shuttle
The space shuttle Discovery's heat shield can be seen in this view from its external tank as the 15-story fuel reservoir fell away from the shuttle as planned after a successful March 15, 2009 launch.
Credit: NASA TV

This story was updated at 9:50 p.m. EDT.

The remains of a Soviet-era satellite pose no threat to the International Space Station and won?t force the massive orbiting lab to move aside before the Tuesday arrival of NASA's shuttle Discovery.

NASA?s Mission Control told station commander Michael Fincke that they won?t have to fire up the outpost?s Russian thrusters to push it clear of a piece of space trash that will zip by early tomorrow.

Discovery and its seven-astronaut crew are due to dock at the space station Tuesday at 5:13 p.m. EDT (2113 GMT), with the spaceflyers spending the bulk of their day today conducting a standard heat shield inspection. The space debris nearing the station also posed no risk to Discovery or its crew, mission managers said.

?We don?t have any threat from this object or any other objects, currently, that we have out there,? LeRoy Cain, NASA?s deputy shuttle program manager, told reporters in an afternoon briefing.

More space trash

The space debris is the second chunk of orbital trash to buzz the station in less than a week, and is due to fly by early Tuesday at about 3:14 a.m. EDT (1714 GMT). It is the leftover remnant of a Soviet military navigation satellite called Cosmos 1275 and not related to last week?s space debris event or the recent increase in orbital trash from a satellite collision last month, NASA said.

?I think it is a random occurrence,? Cain said.

NASA engineers tracked the object throughout the day and determined it would not fly within an imaginary box around the space station that serves as a safety perimeter.

The box about extends 2,400 feet (732 meters) above and below the space station, as well as 15 miles (24 km) to either side of the outpost. The Cosmos 1275 debris was initially expected to glide past within about 2,600 feet (793 meters) of the station, and later found to be outside the perimeter box.

Cain said that the Cosmos 1275 remnant was thought to be relatively similar in size to the debris from a spent satellite rocket motor that flew within three miles (4.8 km) of the space station last Thursday.

That piece of space trash was about 5 inches (13 cm) wide and was flying at about 19,800 mph (31,865 kph). The space station orbits the Earth at about 17,500 mph (28,163 kph).

Notice of the object?s trajectory came too late to move the space station, so Fincke and his crew had to take shelter inside their docked Soyuz spacecraft in case the debris struck the station and forced them to evacuate. The space debris, however, zipped past the space station without incident.

?Space debris is an issue for us,? Cain said. ?There are objects, small and large that we have to contend with so we have to be mindful of the things that are being tracked.?

The amount of space trash has increased in recent months after the Feb. 10 collision of a U.S. and a different Russian satellite, which spewed two debris clouds after the two spacecraft crashed into each other 490 miles (790 km) above Siberia. The new debris has increased the damage risk to NASA?s space shuttle and station flights by about 6 percent, or 1-in-318, NASA officials have said.

?It?s a little bit like traffic on the freeway, sometimes it?s bad sometimes it?s not,? said shuttle flight director Paul Dye, adding that there seems to have been debris events more often lately. ?And sometimes you can figure out why, and sometimes you're not sure where it came from.?

Shuttle in good shape

While engineers on Earth tracked the Cosmos 1275 debris, Discovery astronauts were hard at work scanning their heat shield for damage. The inspection, which uses a sensor-tipped extension of the shuttle?s robotic arm, has been a standard post-launch activity since the 2003 loss of the Columbia orbiter and seven astronauts due to heat shield damage.

At first look, Discovery?s heat shield appears to be in good health, mission managers said. Two more inspections - a photographic survey before tomorrow?s docking at the space station and a later scan similar to today?s - will also be performed during the mission.

?There?s no indication of anything of concern so far,? Cain said.

Dye said the only noticeable glitch has popped up in Discovery?s exercise bike, which has jammed. Discovery carries extra exercise gear, including bungee-like resistance bands, which the shuttle astronauts can use, he added. They will also be able to use gear on the space station once they arrive tomorrow.

Discovery is carrying a $298 million set of U.S. solar arrays and a new crewmember, Japanese astronaut Koichi Wakata, to the space station. The new solar arrays and a final segment of the station?s backbone-like main truss will be installed during three spacewalks planned for Discovery?s flight.

Wakata will replace NASA astronaut Sandra Magnus as a station flight engineer. He is Japan?s first long-duration astronaut and due to return to Earth later this year.

SPACE.com is providing continuous coverage of STS-119 with reporter Clara Moskowitz and senior editor Tariq Malik in New York. Click here for mission updates and SPACE.com's live NASA TV video feed.

  • New Video - Discovery?s STS-119 Night Launch
  • Video - Fragmentation: The Expanding Danger of Space Debris
  • Video: How the Iridium/Cosmos Satellite Crash Happened