MEV gives kiss of life to in-orbit satellites
The reality of on-demand satellite servicing took a giant leap forward with the successful docking of Northrop Grumman’s Mission Extension Vehicle (MEV) to a client satellite.
The first life-extension vehicle to enter the market, the MEV-1 spacecraft, rendezvoused and docked with its client satellite, Intelsat 901 (IS-901), in late February.
The MEV will now use its own thrusters and fuel supply to extend the satellite's lifespan by performing station-keeping manoeuvres in geosynchronous equatorial orbit (GEO) for the duration of the contract.
Joe Anderson, VP of business development and operations for Northrop Grumman subsidiary SpaceLogistics LLC, said the MEV was designed as a multi-use vehicle able to extend the life of satellites that have depleted their fuel supply.
On average, about 20 satellites each year reach this condition and are retired.
‘With the Mission Extension Vehicle, we've taken a very keep-it-simple approach and developed a servicing spacecraft that will dock to a client spacecraft to extend its life,’ Anderson explained.
‘And we stayed docked for the duration of that life extension. It takes over the orbit control of the client, the attitude control of the client satellite, and remains docked for the full duration that the client needs the life extension. When it's finished, it undocks and it can go on and do another service afterwards.’
Launched on 9 October 2019, MEV-1 was initially placed in the graveyard orbit some 300 km above GEO where it rendezvoused with IS-901 at some 11,265 km per hour, docking and moving the client satellite back to GEO.
‘Remember, we're trying to extend the life of satellites that have been in orbit for 15 years or more. They were designed 16, 18, 20 years ago – they were never designed to be reused. They weren't even designed for us to dock to in order to extend their life,’ Anderson said.
‘This was the first time in history that two commercial satellites have ever docked together. It's the first time a rendezvous and docking has occurred in geosynchronous orbits – in the past it was typically done by NASA and others in low Earth orbits. It was also the first time that there's ever been an autonomous docking with a satellite that was not designed to be docked to.
‘After we docked to them, we relocated their satellite, Intelsat 901 satellite, to a new operating position over the Atlantic Ocean region. So, it's now stationary in its new position. And Intelsat has now transferred customers from an older satellite onto this satellite. And so, it's now in-service providing communication services to customers on both sides of the Atlantic.’
The Mission Robotic Vehicle, shown with DARPA's RSGS Robotic Payload, is pioneering robotic servicing of satellites. (Northrop Grumman)
The company is now preparing to launch MEV-2 to undertake a similar life extension mission for Intelsat, although that is likely to be delayed given the effect of COVID-19 on the launch schedule.
SpaceLogistics has also been selected by DARPA as its commercial partner for the agency’s Robotic Servicing of Geosynchronous Satellites (RSGS) programme.
Also utilising the MEV, that effort is studying how to service spacecraft with advanced robotics technology, covering such objectives as in-orbit repair, augmentation, assembly, detailed inspection and relocation of client satellites.
‘We are starting to work on our next-generation system, where we'll have a couple of robotic arms that will be used to do other types of services. So, in addition to grabbing satellites and relocating them, we'll be able to inspect them with the robotic arms. If there's a deployment like a solar array that hasn't deployed properly, we can get underneath and look into what's holding it up and do repairs,’ Anderson said.
‘We can also install other devices onto the spacecraft, other augmentation devices. One of the primary augmentation devices we're looking at today is called a Mission Extension Pod. This will be a much smaller device than our Mission Extension Vehicle that we can just install onto the liquid effigy engine, and it can provide six years of life extension to the client. So that will give us much greater capability to assist other operators.’