Part 1 of 2 Parts
Last week I posted an essay about a new system developed by Tethers Unlimited to deorbit small satellites by unreeling a strip of electroconductive tape at the end of a satellite’s life. This system is under development to help remove small dead satellites in a matter of weeks rather than the many months that are now required. There are tens of thousand pieces of debris from launches and dead satellites now being tracked in Earth orbit. There are over a million pieces too small for radar to spot also in Earth orbit. If this debris keeps piling up, it may become impossible to launch payloads into orbit or beyond. It is critical that we find a way to clean up this orbital debris if we want to continue to explore and exploit space.
The Gateway Earth Development Group is a collection of academics associated with universities around the world. They are working on plans for a space station called Gateway Earth that would have facilities to recycle old satellites and other space junk. They hope to be able to have such a station operational by 2050.
There are two main orbits in use around the Earth. The Low Earth Orbit or LEO extends from about one hundred and twenty-five miles above the Earth to about six hundred and twenty miles. The International Space Station obits the Earth every ninety minutes in LEO. There are thousands of satellites in LEO.
LEO is very crowded and there is a danger of collisions which could result in a shower of debris that could trigger a cascade of showers as further collisions occurred. Technology (such as the Terminator Tape of Tethers Unlimited) is being developed to reduce debris and old satellites in LEO.
Geostationary Earth Orbit or GEO is about twenty-three thousand miles above the Earth. At this altitude, satellites will remain in position over one spot on the Earth as the Earth rotates. This orbit is an excellent place for weather and communication satellites.
When a satellite in GEO reached the end of its operational lifetime, the operators try to move it to a higher orbit two hundred to two hundred and fifty miles above the protected zone where GEO satellites operate. About eighty percent of dead GEO satellites actual make it up to the higher orbit. It is the twenty percent that remain in the protected zone that are a major problem that requires a solution. A recycling space station could be that solution.
The higher orbit is like an abandoned junkyard. Flashes of light are sometimes seen in this orbit which are likely collisions between dead satellites where unused fuel or old batteries explode. There is a danger that dead satellites and collision debris could fall back into the protected zone and threaten operational satellites.
Unfortunately, international space law is not helpful with respect to dealing with dead satellites in GEO and in the graveyard orbit. Dead or out of control satellites cannot be touched without permission of the owners even if those satellites threaten expensive functional satellites.