Space rescue tug ready to work
February 3, 2020
Northrop Grumman’s ‘Mission Extension Vehicle’ the robotic MEV-1 has arrived on station. Launched in October 2019 it is now resting, in orbit, a few hundred kilometres away from its target satellite to be rescued, the 18-years-old Intelsat’s I-901 which is running out of fuel.
MEV-1’s task is to rescue the Intelsat craft, and extend the life of I-901 by about 5 years. The overall mission is that MEV-1 will then detach itself and be ready for another rescue. MEV-1 has the ability to attach itself to about 75 per cent of the satellites in geostationary orbit.
Intelsat 901 will be moved to a so-called ‘graveyard orbit’ a few hundred kilometers higher than the conventional geostationary orbital arc. Then MEV-1 will ‘mate’ with I-901 in a fairly safe zone well away from other orbiting satellites. Docking well away from any other satellites is a further safety measure just in case there’s a glitch.
MEV-1 has an on-board ‘stinger’ which can reach into I-901’s engine nozzle when about 1 metre away from 901. Then mechanical fingers will reach the target satellite to pull the two together.
MEV-1 has a pair of propulsion pods with highly-efficient electric thrusters which can operate for hours or days at a time. And of course, there are cameras on board along with a highly sensitive LiDAR (Light Detection & Ranging) sensor. This is a high-end device often used for land surveying and is also the base technology used in police ‘radar’ speed devices. Its data can be converted in near-real time into a 3D image and its positioning fed into MEV-1’s on-board computer,
Stage 1 is to approach to 80 metres, and if that goes well, to move to 20 metres. Again, if all looks good then the actual ‘mating’ will take place. There will first be a practice run, a rehearsal for what is to follow.
Once the two are connected MEV-1’s primary task is to take the place of Intelsat’s own station-keeping and to maintain the Intelsat correct orbital position. This is no mean feat and will be the first-ever docking between two spacecraft in geostationary orbit, some 36,000 kms over the Equator.
The plan is for the pair, using MEV-1’s thrusters, to then relocate I-901 from its current 18 degrees West inclined orbit position to a new orbital location at 27.5 degrees West, and correctly positioned over the Equator.