Orbiting Politics: Crises in Outer Space
Goldfarb, Greg, Harvard International Review
Greg Goldfarb is a Staff Writer for the Harvard International Review.
On July 24, 1996, a small piece of rocket debris crashed into a French military satellite, sending the satellite spinning end over end. The fragment of rocket that collided with the French satellite was a remnant of a 1986 explosion, caused by the ignition of leftover fuel. The French were eventually able to reestablish control over their satellite. However, the collision marked a dubious milestone: it represented the first high-speed collision of two known, tracked objects in outer space.
The creation of a world without borders requires effective, rapid communication systems, and such systems often require the deployment of satellites. An unintended consequence of our technological world is that space has begun to fill up with both operational satellites and inoperative debris. Much of the debris stems from spent objects such as used rocket stages and separation devices. More still has been produced through explosions and collisions, both intentional and accidental. Since space is a remarkably fragile environment that has little ability to heal itself, the increasing congestion in the Earth's orbital area poses a series of physical and political challenges for the global community to surmount.
Forty years of activity in space and thousands of missions have left roughly 10,000 trackable objects in space. This number fails to account for the greater bulk of the total debris, since tracking systems can only recognize objects greater than one meter in geostationary orbit (roughly 36,800 km from the Earth) and slightly smaller objects in closer, low earth orbits. An estimated 3,000,000 kilograms of orbiting debris now surrounds the Earth, much of it packed into very specific areas and altitudes.
Certainly such numbers seem minuscule at first glance, for space is an incomprehensibly large place. Several factors, however, exacerbate the problems posed by the debris. Most of the debris sits at two altitudes: low earth orbit and geostationary orbit. Low earth orbit is a particularly valuable position for communication satellites, and thus, three-fourths of all satellites sit in this area. Geostationary orbit, in which objects fix to and rotate with a point on the Earth's surface near the equator, bears much of the remaining mass. Moreover, orbits close to the equator are the most valuable positions at both altitudes since they offer the widest possible coverage of the Earth's surface. Thus, satellites and debris orbit in this very confined area of space.
Such congestion presents rather serious physical problems. First, it heightens the danger of collision, which can cause the loss or damage of very expensive equipment. Collisions pose a particularly serious environmental danger since they create a cascading effect in which objects subdivide into more numerous smaller objects, increasing the probability of additional collisions. Large, trackable objects are not the only ones that present this danger. An estimated 50,000 objects from one to twenty centimeters, and billions of objects smaller than a millimeter, provide an equally potent threat. A marble-sized chunk of debris, for example, moving at a relatively normal orbital speed can be as potent as a safe dropped from a ten story building.
Such an illustration is not purely academic. In 1983, for example, a tiny paint chip left by an explosion of a Delta rocket damaged the space shuttle Challenger's window, necessitating replacement at high cost. Numerous satellites have ceased functioning for no apparent reason, and many scientists postulate that the satellites were hit by untrackable debris. One scientist has estimated that a large satellite at an altitude where debris is highly concentrated stands a 10 percent chance of collision. Clearly, the increasing probability of collision in space represents a serious threat to the investments of both private corporations and nations. …