February 21, 2008: Satellite Explodes over Pacific Ocean
"More than 100 metric tons of man-made objects reenter in an uncontrolled fashion each year. Of satellites that reenter, approximately 10-40% of the mass of the object is likely to reach the surface of the Earth. On average, about one catalogued object reenters per day. Approximately a quarter of all objects are of U.S. origin.
Due to the Earth's surface being primarily water, most objects that survive reentry land in one of the world's oceans. The estimated chances that a person will get hit and injured is around 1 in a trillion." Source: Wikipedia - Atomospheric Re-entry
"WASHINGTON (Reuters) - The Pentagon declared on Monday that its mission to blast apart a defunct spy satellite with a missile fired from a Navy warship had been a success.
The strike took place 247 km (153.5 miles) above the Pacific Ocean last Wednesday as the satellite sped through space at more than 17,000 mph (27,000 kph), according to U.S. officials.
"By all accounts this was a successful mission," Marine Gen. James Cartwright, vice chairman of the U.S. military's Joint Chiefs of Staff, said in a statement.
Cartwright said analysis of debris supported the initial conclusion that the missile had most probably destroyed the satellite's tank of hazardous hydrazine fuel as intended.
"From the debris analysis, we have a high degree of confidence the satellite's fuel tank was destroyed and the hydrazine has been dissipated," he said.
Experts were tracking less than 3,000 pieces of debris, all smaller than a football. "The vast majority of debris has already reentered or will shortly reenter the Earth's atmosphere in the coming days and weeks," Cartwright said.""The Kessler Syndrome is a scenario, proposed by NASA consultant Donald J. Kessler, in which the volume of space debris in Low Earth Orbit is so high that objects in orbit are frequently struck by debris, creating even more debris and a greater risk of further impacts. The implication of this scenario is that the escalating amount of debris in orbit could eventually render space exploration, and even the use of satellites, too prone to loss to be feasible for many generations.
The Kessler Syndrome is especially insidious because of the "domino effect and Feedback runaway." Any impact between two objects of sizable mass will create additional shrapnel debris from the force of collision. Each piece of shrapnel now has the potential to cause further damage, creating even more space debris. With a large enough collision (such as one between a space station and a defunct satellite), the amount of cascading debris could be enough to render Low Earth Orbit essentially impassable."
Labels: Space debris