Space Industry First - A Satellite Docks With Another

In an historic first, two unmanned satellites docked with each other in orbit this Tuesday.  The feat was announced by Northrup Grumman, whose SpaceLogistics subsidiary created the satellite that achieved the docking.  Northrup heralded the mission as an "historic accomplishment" in the field of satellite servicing. Prior to this mission, no two commercial spacecraft had ever docked in orbit before.

Northrop Grumman Corporation (NYSE: NOC) and the company’s wholly-owned subsidiary, SpaceLogistics LLC, have successfully completed the first docking of the Mission Extension Vehicle-1 (MEV-1) to the Intelsat 901 (IS-901) spacecraft in order to provide life-extension services. This historic accomplishment marks the first time two commercial satellites have docked in orbit and the first time that mission extension services will be offered to a satellite in geosynchronous orbit.

MEV-1 was launched from Russia aboard a Proton rocket last October 9th, and the satellite's small ion thrusters took three months to get the satellite high enough to reach the geostationary orbit belt at about 22,250 miles, where the orbital period matches the Earth's rotation and the satellite stays motionless in the sky as seen from the ground.  The Intelsat (IS-901) spacecraft was launched in 2001 and was pulled from active service in December 2019 as it ran low on fuel.  Operators commanded the satellite to move into a "graveyard orbit" farther out than the unique geostationary space. It is here that MEV-1 linked up with the communications satellite on Tuesday.  Northrup uses a mechanical docking system that can be glimpsed in this animated GIF from the MEV-1 as it captures the IS-901.  There's a short graphic at Popular Mechanics that might help you visualize it better.  The system latches onto existing features on the satellite; in this case the satellite's engine.  Northrup says it's designed for multiple docking and undockings and can deliver over 15 years of life-extension services.

This is not refueling on orbit, as we talked about last August; the Intelsat IS-901 wasn't designed to allow refueling.  I'd be sure that's true for everything else currently on orbit.  The Mission Extension of the MEV-1's name is achieved by grappling the satellite and having the MEV-1 bring it back into the geosynchronous orbit where they will remain attached for years.  Ars Technica reports:

According to Northrop Grumman, the combined spacecraft stack will now perform on-orbit checkouts before MEV-1 starts to relocate the combined vehicle back into geostationary orbit, where Intelsat 901 will continue in service for five additional years.

Northrup plans to launch a Mission Extension Vehicle-2 later this year.  Northrop also said this is its first step toward establishing a fleet of satellite servicing vehicles that not only extend the life of satellites like this mission, but provide orbital inclination changes, can provide spacecraft inspections and perform in-orbit repair and assembly. 

Final words to Eric Berger at Ars Technica:

As Earth orbit becomes more congested, a number of companies are working to develop technologies to both service vehicles as well as remove orbital debris from space. Tuesday's successful docking seems to be a positive step forward into a future in which on-orbit spaceflight becomes more sustainable, where spacecraft connect, assemble, and operate in a more coordinated way.