Astronomy Journal Entry
Collision Adds More Space Junk (March 16, 2009)
Space junk is a growing problem. About 95 percent of all objects in the sky are junk. The dots show this debris but are not drawn to scale. NASA.
Last month, a U.S. commercial satellite and an old Russian satellite smacked head-on in outer space. The violent collision sent thousands of pieces of new space junk flying off in all directions. The debris, which could threaten spacecraft or other satellites for up to 10,000 years, raises the alarm about the growing danger of space junk.
There's already lots of space junk up there. Out of nearly 20,000 objects orbiting Earth that are big enough to show up on radar, only 900 are satellites. The others are trash. On top of that, there may be 300,000 other objects too small (less than 4 inches or 10 cm) for radar to see.
Space junk is already causing problems. Space shuttle astronauts notice holes on satellites they work on in space. The holes are from high-speed collisions with tiny bits of debris.
Scientists are having a tough time figuring out what to do about the problem. One idea is to attach balloons to low-orbit junk to increase atmospheric drag so the pieces will fall to Earth faster. Even more out of the box is the idea to attach an electrodynamic wire to space trash to generate electric current controlled from the ground. Neither these nor any other ideas suggested so far are practical or affordable.
In the meantime, scientists hope nations of the world will get better at pooling radar data showing where the space junk is. This should at least improve the odds that spacecraft can dodge the most dangerous chunks.
