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.
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