- NEW YORK - In June of 1965, Edward White lost one of his gloves at the
end of a space walk during NASA's Gemini IV mission.
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- On Earth, dropped items like nuts, bolts
or an old glove might kick around and eventually be swept away or dug up.
But in space, discarded garbage becomes deadly. Like bullets in perpetual
motion, any free-floating item in space travels in an orbit at average
speeds of seven miles per second.
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- "A piece of debris the size of a
penny would hit you like a Volkswagen going along at 80 mph because of
its velocity," said Claude Phipps, a space engineer at Photonic Associates
in Santa Fe, New Mexico.
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- Fortunately White's glove caused no damage
before it fell back to Earth and burned upon re-entry a few days later.
But if White had performed his space walk a few more hundred miles further
above the planet, chances are his glove would still be hurtling around
in space.
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- Considering the vast expanse that makes
up the upper orbits, a few dropped items here and there may not be much
to worry about. As Nick Johnson at NASA's space debris division said, "No
one's dodging debris out there." But numerous space shuttles, satellites,
and space stations have taken a beating and the problem is growing. Space,
the so-called Last Frontier, is becoming less empty by the minute.
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- Last year alone, companies and government
programs launched 77 new satellites to service cellular phone networks,
global positioning systems, and cable television reception. Although the
growing number of satellites may eventually pose some problems, the main
worry now lies with the debris these and other launches leave in their
wake.
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- Among the junk circling Earth are billions
of paint chips - each with the power to take a chink out of a space shuttle
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- Reports from the U.S. Space Command,
under the U.S. Air Force show that the amount of junk larger than 10 cm
in diameter has increased by a rate of 200 objects every year. Right now
there are more than 8,000 basketball-sized items hurtling around the Earth.
The amount of smaller man-made debris is even more daunting. Johnson estimates
there are at least 100,000 shards of garbage more than 1 cm in size and
billions of items smaller than 1 cm now orbiting the planet.
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- More than 40 years of space exploration
has taken its toll. Space missions have left behind refuse like expired
spacecraft, the upper stages of launch vehicles, nuts and bolts released
as spacecraft separate from launch vehicles, tools dropped during space
walks, and the shards from explosions or collisions in the upper orbits.
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- It's the smaller debris that has most
scientists worried. Two past flight maneuvers, including one during John
Glenn's recent return to space, have shown pilots can dodge a large piece
of debris when given ample warning by ground-based monitors. But there's
no way to see a small chunk of junk coming. In fact, one way NASA gauges
how much small debris is out there is by assessing the damage to space
stations like the Mir and returned space shuttles.
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- NASA - A recovered piece of silica glass
with an impact fracture
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- "We end up replacing one shuttle
window every flight due to its striking small particles," said Johnson.
Replacing an odd window may not seem like much trouble, but at $40,000
a window, haphazard encounters with space debris have become an expensive
problem. Some of the damage is caused by natural meteor shards, but tests
on the remains of objects in the windows show more than half are man-made.
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- Tiny flakes of paint are actually one
of the most common items inflicting the damage. Before satellites are launched
into upper orbit, most are coated in layers of aluminum paint to help maintain
a steady temperature. As on an aging house, chips of the paint flake away
from the satellites after a couple of years. NASA estimates there are billions
of paint particles soaring in space " each with the power to take
a chink out of a shuttle or space station window.
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- It's relatively easy, albeit expensive,
to fix the damage to a space shuttle since it returns to Earth " and
to the care of its engineers. But for a craft like the International Space
Station, a simple ding inflicted by a small piece of debris is difficult
to repair in orbit and can become a thorn in the craft's side. And, of
course, a hit by a larger piece of debris would be deadly.
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- The International Space Station
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- To protect the massive floating craft
from debris, NASA engineers plan to install more than 200 different shields
at the space station's most sensitive points such as living quarters for
the astronauts or fuel tanks. The shields are made up of layers of aluminum
and Kevlar, but can only offer protection from items smaller than 1 cm.
The station is also equipped with engineering to move itself away from
large space trash items.
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- But when it comes to middle-sized chunks,
the station will basically be a sitting duck.
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- "It's a real issue," said Johnson.
"The space station is going to be so large and it's going to be up
there for such a long time that the probabilities of getting hit catch
up to you."
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- One way to avoid collisions is to track
every piece of man-made debris as it travels in its orbit - and then dodge
as it approaches.
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