Early in 2015, an expired military weather satellite, Defense Meteorological Satellite Program (DMSP) Flight 13, exploded in a sun synchronous orbit. The official cause given by the Defense of Department was a temperature spike resulting in a blast. This was a 20-year old spacecraft that was still operational, but downgraded to a backup spacecraft in the DMSP constellation that provides weather data to Navy and Air Force meteorologists.
Although the loss of this satellite had a minor impact on the collection of data for military operations, the explosion did result in a significant increase in orbital debris in a sun synchronous orbit. At first this may not appear to be important, because space is thought of as being "BIG." While space is in fact big, this is a relative concept. Empty space is certainly big.
However, a spherical shell of space bound by a lower limit of about 700 km altitude and an outer limit of about 1200 km that occupies millions of pieces of debris, expired satellites, old rocket bodies and active satellites is no longer "BIG."
Imagine trying to fly and navigate in this volume with millions of objects all travelling at speeds of over 7 km/sec in all directions. The chances of avoiding any collisions with debris pieces over the lifetime of a satellite are extremely small.
To make the situation worse, the number of debris items is exponentially increasing. Nevertheless, space-faring nations continue to launch new satellites into the same debris-laden regions of space. If we add up all of the proposed broadband LEO constellations plus the large number of small satellites that are being developed, the debris build up rate will be even higher than is has been in recent years.
Is anyone doing research on this issue? Yes, NASA and other organizations have been studying the problem and have recommended steps to limit new debris. But, is anyone seriously investing in debris remediation solutions which would lead to cleaning up space. The sad answer is, No.
Unfortunately, doing nothing is not acceptable. If this situation continues unabated space will reach gridlock. In other words, there will be no satellites that can survive above about 700 km. Most of the important space-based applications will cease to exist. This could mean no more GPS, weather satellites, satellite based TV broadcasts, communications and many national security activities. Much of the modern world as we know it may revert back to the 1970s.
