February 3, 2011
Pentagon Report Warns Of Future Space Junk Collisions
A Pentagon report warned that space is so littered with debris that a collision between satellites could set off an "uncontrolled chain reaction" capable of destroying the communications network on Earth.
Scientists said that the volume of abandoned rockets, shattered satellites and missile shrapnel in Earth's orbit is reaching a "tipping point" and is now threatening the $250 billion space services industry.
The report said that a collision between two satellites or large pieces of space debris could send thousands of pieces of "space junk" spinning into orbit, each capable of destroying further satellites.
Global positioning systems, international phone connections, television signals and weather forecasts are among the services at risk of crashing.
The U.S. Defense Department's interim Space Posture Review warned last year that this "chain reaction" could delve some orbits so cluttered that they become unusable for commercial or military satellites.
There are also fears that large pieces of debris could threaten the lives of astronauts in space.
The report said space is "increasingly congested and contested" and warned the situation will get worse.
Bharath Gopalaswamy, an Indian rocket scientist researching space debris at the Stockholm International Peace Research Institute, told The Telegraph there are over 370,000 pieces of junk compared with 1,100 satellites in low-Earth orbit (LEO), which is between 490 and 620 miles above the planet.
The crash between a defunct Russian Cosmos satellite and an Iridium Communications Inc. satellite in February 2009 left about 1,500 pieces of junk whizzing around the earth at 4.8 miles per second.
According to Dr. Gopalaswamy, a Chinese missile test destroyed a satellite in January 2007, leaving 150,000 pieces of debris in the atmosphere.
The space junk also comprises nuts, bolts, gloves and other debris from space missions.
"This is almost the tipping point," Dr Gopalaswamy said. "No satellite can be reliably shielded against this kind of destructive force."
The Space Posture Review said in May that the Chinese missile test and the Russian satellite crash were key factors in getting the U.S. to help the U.N. issue guidelines urging companies and countries not to clutter orbits with junk.
The United Nations Office for Outer Space Affairs (UNOOSA) urged the removal of spacecraft and launch vehicles from the Earth's orbit after the end of their missions.
Director of UNOOSA, Mazlan Othman, said space needs "policies and laws to protect the public interest."
He added: "We should have all the instruments to make sure that lifestyles are not disrupted because of misconduct in space when people switch the television to watch the World Cup next month in Johannesburg."
On the Net:
- US Dept of Defense
- Space Posture Review
- Stockholm International Peace Research Institute
- United Nations Office for Outer Space Affairs (UNOOSA)