Are Satellites in Danger?

The particles that make up meteors are very small, smaller than the diameter of a human hair, and tend to burn up at very high altitudes. None reach the surface of the Earth. Hence, there is no danger to the Earth's surface or to aircraft.

In space, however, we have a different story. Although the particles of rock and dust are very small, the encounter velocity is enormous--about 71 km/second (or over 155,000 miles per hour, over 200 times the speed of sound). The result is that even a grain of sand the size of the head of a pin has the same energy as a .22 caliber bullet. At these speeds, the impact of a particle smaller than the diameter of a human hair can create an electrically charged cloud, a plasma, to form. This plasma can cause a sudden electrical pulse which can upset sensitive electronics. Impacts of small particles can also cause pitting of optical surfaces and mirrors, degrading the performance of critical sensors.

There are over 500 operational spacecraft now in orbit about the Earth, and they could, theoretically, be sand-blasted during the passage through thick cometary debris. Given what we know now, the intensity of a meteor "storm" could result in tremendous damage. Scientists do not know what the actual level of danger is for satellite damage, but with the world-wide dependence on satellite communication ever growing, there is a house of cards dimension to this potential disaster. It is unlikely that a large number of satellites will be "knocked out" but it is possible that some satellites will be damaged. The likely source of damage will not be from a rock "blasting a hole" in a satellite, but rather, from the creation of a plasma, or free electric charge on the spacecraft. The charge could cause damage to computers and other sensitive electronic circuits on board the spacecraft, and ultimately cause the spacecraft to fail. For example, during the 1993 Perseid meteor shower, it was determined that the Olympus communications satellite was damaged by a meteor strike and went off the air shortly thereafter as a result of an electrical failure.

Of course, no one can guess the exact severity of a meteor storm. Like many acts of nature, man cannot predict with certainty what will happen. It always remains possible that the great, unexpected storm could cause wide spread damage to the delicate network of satellites. Some information from Aerospace Corporation