Jun 22, 2020 08:00:00

A project to bring back 'dead satellites' from the artificial graveyard and reuse them

Human beings are launching artificial satellites for various purposes such as communication and earth observation, but because artificial satellites have a limited life span, processing of used artificial satellites and the generation of

space debris are becoming a problem. Meanwhile, a small spacecraft called ' Mission Extension Vehicle (MEV) ' jointly managed by NASA with Northrop Grumman may play an important role in extending the life of the satellite. I am.

Zombie Satellites Return From the Graveyard-IEEE Spectrum
https://spectrum.ieee.org/tech-talk/aerospace/satellites/zombie-satellites-return-from-the-graveyard

As a processing method for artificial satellites, most of the main body is burned out by the heat when it re-enters the atmosphere, by dropping it towards the spacecraft cemetery (spacecraft graveyard), which is a sea area that spreads between the middle of New Zealand and South America. There is a way. Another method is to move a geostationary satellite launched into a geostationary orbit (GEO) at an altitude of 35,786 km above the equator to a special orbit called the graveyard orbit or graveyard orbit , which is 200 to 300 km higher, and another artificial satellite. There are things to prevent from colliding with.

Most geostationary satellites have a designed life of about 15 years, so the amount of fuel on board is sufficient to operate for this life. The International Inter-Agency Space Debris Coordination Committee (IADC) mandates that geostationary satellites be guided into orbit in the graveyard if they do not drop the completed geostationary satellites to Earth.

However, Jonathan McDowell, who works at the Harvard Smithsonian Astrophysics Center , said that 365 satellites could not enter the graveyard orbit due to malfunction, lack of planning, idleness, etc. Pointed out that he continues to drift in outer space with his nature. By contrast, there are only 283 satellites that have moved to the graveyard orbit following the IADC's recommendations, 'I'm a little disappointed with the level of compliance,' McDowell said.

While the processing of artificial satellites has become a problem, it is often the case that the functions of artificial satellites are not lost even if the fuel for moving is exhausted. Joe Anderson, vice president of Space Logistics, a subsidiary of Northcrop Grumman, pointed out that even if the satellite has been in operation for more than 15 years, there will be little technical deterioration other than fuel. I will. As far as Anderson knows, there are cases where a satellite has continued to provide services to the Earth for nearly 30 years.

Therefore, NASA and Northcrop Grumman launched in collaboration with the first MEV, the MEV-1 . In February 2020, MEV-1 docked with Intelsat-901 , a communication broadcasting satellite that was wonderfully floating in the orbit of the graveyard, and succeeded in guiding from the graveyard orbit to the geosynchronous orbit using the fuel carried by MEV-1 .. At the time of writing the article, Intelsat-901 started operating again and provided services to over 30 operators.

Thus, some satellites in orbit in the graveyard are out of fuel and cannot adjust their orbits, but other systems continue to function without problems. MEV is a small spacecraft that can be used again by docking with such satellites and adjusting the orbit. MEV-1 will adjust the orbit of Intelsat-901 for the next 5 years and then guide it again to the graveyard orbit, but since MEV-1 itself can operate for more than 15 years, it docks with another satellite as it is I can do it.

The MEV-1 is just the beginning, and the second MEV will be put into geosynchronous orbit in 2021. In addition, Northcrop Grumman is also developing a 'mission expansion pod' that can extend the missionable period by up to 6 years just by mounting it on an artificial satellite, and it seems that it plans to launch it in 2023.

While Northcrop Grumman uses MEVs to 'prolong the life of satellites,' McDowell can use the system to solve the problems of growing space debris and satellites out of orbit. I think. 'There is an era of space garbage trucks,' McDowell said, saying that there is a future of guiding a non-functioning satellite to a graveyard orbit with a spacecraft like MEV.