Mission Extension Vehicle 1 (MEV-1), built and operated by SpaceLogistics LLC, a subsidiary of Northrop Grumman, made history again by undocking from a satellite in low-Earth orbit for the first time. MEV-1 made its first significant achievement on February 25, 2020, when it docked with the retired Intelsat IS-901 communications satellite in orbit 36,000 kilometers above the Earth’s surface.
Image source: Northrop Grumman
Amazingly, the $250 million IS-901 satellite was fully operational even after 15 years of operation. The only reason it was taken out of service and moved to the so-called graveyard orbit, where spacecraft are sent after their service life ends, was because it ran out of fuel, which is needed to keep the satellite in the desired orbit and its correct positioning in space.
Instead of abandoning fully functional equipment, a decision was made to create a MEV spacecraft designed to return obsolete satellites to service. It is capable of docking with devices that do not have a docking mechanism in their design. For this purpose, the MEV-1 design includes a special probe that is inserted into the nozzle of the satellite’s main engine and fixed there. After this, the MEV-1 takes over the functions of the propulsion system and position control, thanks to which the communications satellite was returned to service.
It all sounds simple enough, but in reality the success of the project is based on extremely complex engineering solutions. Docking a satellite in geostationary orbit with a robotic spacecraft is a very difficult task. It took three months to approach the ship with the satellite, analyze its position in space and choose the right time for docking. After specifying all the parameters, it was necessary to slowly approach the target, avoiding a collision, extend small manipulators that managed to latch onto the satellite, and then place and secure the probe in the nozzle of its engine.
Intelsat IS-901 satellite image taken by MEV-1 camera
MEV-1 successfully docked with IS-901 in 2020, returning the satellite to service for another five years. Before undocking earlier this month, MEV-1 returned IS-901 to a graveyard orbit. Meanwhile, MEV-2 is expected to remain docked to Intelsat 10-02 for at least another four years.
Similar vehicles are likely to be used more and more in the future. Improved models will likely be able to perform not only propulsion functions, but also refuel and repair satellites. In the more distant future, vehicles may be able to disassemble obsolete satellites to extract components that can be used to repair other space objects. As for MEV-1, it has already set course for a new target, but which satellite will be its next partner is still unknown.