Mission Extension Vehicle

The Mission Extension Vehicle (MEV) is a spacecraft that extends the functional lifetime of another spacecraft through on-orbit satellite servicing. They are 2010s-design small-scale in-space satellite-refueling spacecraft first launched in 2019. The MEV spacecraft grew out of a concept proposed in 2011 by ViviSat, a 50/50 joint venture of aerospace firms US Space and Alliant Techsystems (ATK). The joint venture was created in 2010 for the purpose of designing, producing and operating the MEV program.

Since the original conception of the MEV program by the ViviSat company, the Vivisat venture was shut down for a time, and the company was dissolved by Orbital ATK in April 2016.[1] The MEV program continued on as a solo-project of Orbital ATK, which was subsequently purchased by Northrop Grumman in 2018. The MEV program continued under Northrop Grumman[1] and in 2019, launched MEV-1 to dock and reposition Intelsat 901, an objective reached in April 2020. Servicing an on-orbit satellite in this way was a space industry first for a telerobotically operated spacecraft, as satellite servicing had previously been accomplished only with on-orbit human assistance in the several missions to service the Hubble Space Telescope.

History

ViviSat proposed the Mission Extension Vehicle (MEV) concept in 2011.[2] At that time, the project was planned to be a 50/50 joint venture of aerospace firms US Space and Alliant Techsystems (ATK), to operate as a small-scale in-space satellite-refueling spacecraft. In the joint venture, ATK was to be responsible for the technical design, production and operation of the satellite, and US Space would be responsible for the financing and business-side of operations.

By March 2012, ViviSat was finalizing its design and was "ready to build" the servicing spacecraft,[3] but had announced no customers for the Mission Extension Vehicle services.[3]

In April 2014, ATK announced that it would merge its Aerospace and Defense Groups with Orbital Sciences Corporation.[4]

Missions

Technical capabilities and competition

ViviSat saw competition for space servicing business with the 2011 announcement of the Space Infrastructure Servicing (SIS) vehicle from MacDonald, Dettwiler and Associates (MDA). However, the two vehicles intended to operate with different technology approaches. Whilst the ViviSat design connects to the target satellite and uses "its own thrusters to supply attitude control for the target".,[21] SIS MDA would open the satellite's fuel lines, refuel it, then depart.

In a June 2012 article in The Space Review, a number of approaches to satellite servicing were discussed. ViviSat's Mission Extension Vehicle was reported to operate at the "less complex" end of the technology spectrum,[3] which could offer higher reliability and reduced risk to satellite owners.

ViviSat believed their approach was simpler and could operate at lower cost than MDA, while having the technical ability to dock with "90% of the 450 or so geostationary satellites in orbit",[21] whereas MDA SIS could open and refuel only 75%.[22]

See also

• ConeXpress – an ESA concept vehicle to perform the same mission.
• Orbital Express – a 2007 Federal government of the United States, DARPA-sponsored mission to test in-space satellite servicing technologies with two vehicles designed from the start for on-orbit refueling and subsystem replacement.
• Propellant depot