- The Washington Times - Saturday, February 15, 2003

Space has become a treacherous junkyard of dead satellites, tools and other astronomical garbage that zip around at speeds up to 17,000 miles per hour.
With an estimated 110,000 pieces of space junk orbiting the Earth, the National Aeronautics and Space Administration has been unable to discount a collision between orbital debris and the Space Shuttle Columbia as a contributing factor in its fiery crash Feb. 1.
Confirmation by the Columbia Accident Investigation Board Thursday that superheated gas seeped through a hole in the shuttle's exterior lends credence to theories that it was damaged by insulating foam during takeoff or by orbital debris at another time during the 16-day mission.
"Is it possible [that gas seeped in through a hole]? I'd have to say yes, it is possible," NASA flight director Leroy Cain said during a press conference yesterday to discuss what happened inside mission control at Johnson Space Center in Houston during the shuttle's descent.
Investigators said yesterday they are still examining what caused the hole in the shuttle's exterior.
"I don't see how they could rule [orbital debris] out. But then there are myriad things that could be a factor," said Rick Hauck, a former astronaut, chief executive of aerospace firm AXA Space and chairman of a committee that wrote a 1997 report on the risk of orbital debris to shuttles.
Orbital debris has accumulated since 1957, when the Soviet Union launched Sputnik. A screwdriver, wire carrier and a socket also contribute to the celestial junkyard.
The U.S., Soviet and Russian space agencies are responsible for about 90 percent of the junk.
NASA launched Vanguard I, the second U.S. satellite, in 1958. It functioned for six years becoming space junk in 1964.
One of the most unusual pieces of debris began its accidental orbit in 1965, when Gemini 4 astronaut Edward White lost a glove during the first American spacewalk. It remained in orbit for just a few months.
With the growing volume of junk, collisions between spacecraft and orbital debris become more likely. NASA considers the chance of catastrophic damage to be low right now. Even though shuttles get slammed repeatedly by space junk, the space agency never has been able to point to a single example of debris causing significant damage, said Nick Johnson, NASA chief scientist and program manager for orbital debris.
But the potential for a collision exists, and even tiny debris is cause for concern, according to the 1997 study by the National Research Council. The study, funded by NASA, concluded that tiny objects pose a particular problem because they can cause critical damage to a shuttle but are too small to be tracked.
NASA's shuttles were not built to withstand bombardment from orbital debris. A strike to the leading edge of a wing could cause catastrophic damage, according to the report.
"Impacts that penetrate the leading edge of a wing or the lower surfaces of the wing … might not be immediately critical or even detected but the consequent thermal heating on re-entry could have a 'blowtorch' effect inside the wing that causes loss of flight control or failure of the primary structure resulting in the loss of the vehicle," the report said.
NASA investigators are focusing on Columbia's left wing because sensors indicated multiple problems there.
The only known damage from orbital debris occurred in 1996 when a French satellite was struck but not destroyed by a fragment from a European rocket booster that was moving at 31,000 miles per hour.
"That's the kind of scenario we're trying to avoid," Mr. Johnson said.
NASA and the U.S. Air Force Space Command, in Colorado Springs, use radio waves to keep constant watch on space so they can alter the orbit of spacecraft that are on a collision course with space junk.
About 11,000 pieces are large enough to be monitored daily by NASA and the military. Those fragments are at least 4 inches in diameter and include 3,400 fragments from exploded rocket boosters, 2,100 nonfunctional satellites and 1,000 pieces of litter, from straps to covers for sensors.
The problem isn't going away. The U.S. Air Force Space Command estimates the amount of space junk increases about 3 percent a year, said Maj. Bob Rochester, chief of the Space Analysis Center.
And there's no way to retrieve junk left behind.
"There have been lots of ideas, but they're either not technically feasible or not economically viable," Mr. Johnson said.

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