Source: Xinhua
02-13-2009 12:08
Special Report: Tech MaxBEIJING, Feb. 12 (Xinhua) -- A Chinese space expert said on Thursday that the massive debris of the satellite collision might pose grave but controllable danger to other spacecrafts in case they hit them.
"The debris of the two big satellites may create holes on other spacecrafts, or even bigger losses, once they hit them," Pang Zhihao, a Chinese expert on space techniques, told Xinhua.
"The degree of the possible danger's graveness depends on the number, size and flying direction of the debris," he said.
He predicted that a debris's flying speed may reach 7.8 kilometers per second, or even faster, and may remain in space for decades.
According to Pang, space waste mainly consists of defunct satellites and satellite detectors, entire spent rocket stages as well as junks or belongings tossed out by astronauts.
There are approximately 17,000 pieces of space debris that are larger than 10 cm and can be currently detected. The number of pieces smaller than 10 cm is up to 10,000. They were mainly produced by the United States and Russia.
But such a large amount of debris has not crowded the near-Earth space, Pang said.
The expert mentioned that there are several ways to monitor the situation in a bid to prevent any danger to the space station as many fear that the debris might hit the station, thereby threatening the safety of the astronauts in the station.
Pang said the monitoring on spacecrafts should be enhanced and the defunct crafts in space should be taken under remote control so as to limit such dangers in the future.
The ability of orbit changing of the spacecrafts is very important, pang said.
The cause of the collision was still unknown, Pang said, adding it depends on further details by both U.S. and Russian space administration.
The collision, which occurred at 11:55 a.m. EST (1655 GMT) Tuesday, involved a 560-kg U.S. Iridium commercial satellite launched in 1997, and a 900-kg Russian satellite launched in 1993 and presumed non-operational.
The Russian Federal Space Agency has confirmed the collision to Xinhua, but it refused to make any comment on the incident.
In 1996, a French communication satellite was hit by a piece of debris from Ariane 5, which left damages on an observation equipment. Similar incidents occurred several times but it was the first such collision between large satellites in space.
Space junk has posed a growing concern in the countries which pursue space exploration in recent years, since collisions at orbital velocities can be highly damaging to functioning satellites and can also produce even more space debris.
Editor:Yang Jie
