How dangerous could a bit of litter the size of a corn kernel be? In outer space, very. A minuscule fleck of paint traveling at orbital speed can smash the windshield of a space satellite. And NASA mathematicians say something as small as a grain of sand can have an impact equivalent to the power of a bowling ball moving at 100 miles per hour.
The volume of space junk orbiting 1,000 kilometers—some 621 miles—above the earth is burgeoning and posing a growing risk to millions of dollars worth of orbiting weather, communications and surveillance satellites from countries all over the world. The stuff includes old rocket boosters, derelict space craft and random pieces of technological equipment.
Mathematical analysis by two Stanford University researchers suggests
if space programs around the world were forced to remove their own trash, the increasing chance that a live satellite would be damaged by passing debris would be vastly reduced.Lawrence Wein
, the Paul E. Holden Professor of Management Science at Stanford Graduate School of Business and Andrew Bradley, a doctoral student at Stanford’s Institute for Computational and Mathematical Engineering, say nations should be required to comply with existing rules against space littering and face fines and taxes if they don’t. Their paper, "Space Debris: Assessing Risk and Responsibility,”
was recently published in Advances in Space Research.
The danger was highlighted recently when a derelict Russian satellite and a working American commercial communications satellite collided in outer space
, sending clouds of speeding debris into orbits 300 to 800 miles above the earth. It was the first such collision, but not the first danger. Astronauts aboard the International Space Station
had to take refuge in their escape capsule March 12 as a piece of flying junk whizzed by. NASA officials explained the astronauts did not have time to maneuver out of the way because the small size of the debris—five inches long—and its elliptical orbit made it hard to track.
The Chinese deliberately blew up one of their own satellites
a year ago, adding to the junk. A Wall Street Journal video
, with narrative noting there may be millions of pieces of man made litter in space, illustrates the magnitude of the unpredictable risk.
A Stanford Graduate School of Business release says NASA has suggested creating space equipment to lasso some of the junk fragments and drag them closer to the earth’s atmosphere, where friction would burn them up. But Wein says there is no cost effective way to do that. He explains that all satellites are supposed to have enough fuel to propel them downward when their life cycle ends, but international compliance is only about 50 percent. NASA requires junk removed within 25 years of its launch, and the European Union
wants more regulation.
"It appears that if full compliance of the 25-year spacecraft de-orbiting guidelines can be achieved within the next few decades and (if) no anti-satellite weapons are used or tested…the lifetime risk of debris…may be sustainable at a tolerable level,” they write in their paper. They suggest fees and fines for violators, but concede "the political and economic issues associated with establishment of such fees are fairly daunting.”