A Mission Extension Vehicle (MEV)  is a type of spacecraft designed to extend the functional lifetime of another spacecraft. 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 of 2016. 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 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.
ViviSat proposed the Mission Extension Vehicle (MEV) concept in 2011. 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.
In the timeframe 2013-2016, the partners ATK and US Space fell out concerning the joint ViviSat-venture. The situation ended with ATK (which in the meantime in 2015 had merged with Orbital Sciences Corporation to become Orbital ATK) taking control and dissolving the ViviSat-company on 5 April 2016. The MEV program continued as Orbital-ATK only project.
In December 2017, the US telecommunications regulator approved a plan submitted by Orbital ATK to use an MEV to service an Intelsat satellite, Intelsat 901, that was originally launched to geostationary orbit in June 2001 for a planned in-service life of 13 years. That satellite had already been replaced in orbit. The first MEV, MEV-1, was then planned to launch with Eutelsat's Eutelsat 5 West B commsat, no earlier than 2019. MEV-1 also needed a licence from National Oceanic and Atmospheric Administration (NOAA). The NOAA license is required because the MEV-1 has cameras for docking that could also image the Earth, thus necessitating a remote-sensing license.
MEV-1 was set to launch on a Russian Proton-M rocket along with Eutelsat 5 West B satellite on 30 September 2019, but the launch was postponed to 9 October 2019 due to issues with the integration of control systems of Briz-M orbit insertion stage and the satellites. MEV-1 was launched on 9 October 2019.
MEV-1 rendezvoused with Intelsat 901 on 25 February 2020 at 07:15 UTC, and by April 2020 had repositioned the commsat so that it could come back on line in its designated geosynchronous spot, a space industry first for a telerobotic spacecraft, and something that had only previously been done on the Hubble Space Telescope servicing missions with direct human assistance. The goal is to extend its operational life by five years via in-orbit stationkeeping. After the Intelsat 901 mission ends, MEV-1 is designed to be able to dock and undock additional times, potentially enabling it to service additional satellites.
- MEV-1 — launched on 9 October 2019 on a Proton rocket; rendezvoused with Intelsat 901 on 25 February 2020; satellite initial servicing and repositioning completed with Intelsat-901 returned to service on 2 April 2020; expected end of mission with Intelsat-901 in 2025.
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"., 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, 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", whereas MDA SIS could open and refuel only 75%.
"In addition to extending the life of an out-of-fuel satellite, the company could also rescue fueled spacecraft like AEHF-1 by docking with it in its low orbit, using its own motor and fuel to place it in the right orbit, and then moving to another target".
- 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
- "ViviSat Corporate Overview". company website. ViviSat. 2009. Archived from the original on 24 January 2018. Retrieved 28 March 2011.
- Morring, Frank, Jr. (22 March 2011). "An End To Space Trash?". Aviation Week. Retrieved 21 March 2011.
ViviSat, a new 50-50 joint venture of U.S. Space and ATK, is marketing a satellite-refueling spacecraft that connects to a target spacecraft using the same probe-in-the-kick-motor approach as MDA, but does not transfer its fuel. Instead, the vehicle becomes a new fuel tank, using its own thrusters to supply attitude control for the target... [the ViviSat] concept is not as far along as MDA.
- Foust, Jeff (25 June 2012). "The space industry grapples with satellite servicing". Space Review. Retrieved 4 July 2012.
- "ATK Press Release". ATK Announces Plan to Create Two Independent, Publicly Traded Companies Committed to Leadership in Outdoor Sports and Aerospace and Defense. 29 April 2014. Archived from the original on 20 February 2015. Retrieved 20 February 2015.
- "FCC begins approval of Orbital ATK satellite-servicing mission for Intelsat-901". 5 December 2017.
- Ракету "Протон-М" со спутниками установили на стартовый стол [Proton-M rocket with satellites erected at launch pad]. RIA Novosti РИА Новости (in Russian). 5 October 2019.
- Wall, Mike (9 October 2019). "First-of-Its-Kind Satellite Servicing Spacecraft Launches on Russian Rocket". Space.com.
- "A Meeting in Orbit Demonstrates a Space Junk Solution". nytimes.com. 26 February 2020.
- "Northrop Grumman MEV-1 Servicer Docks with Intelsat Satellite". 26 February 2020.
- Northrop Grumman [@northropgrumman] (10 September 2019). "MEV-1, scheduled to launch September 30, will provide five years of life extension to the INTELSAT 901 satellite. Learn more about MEV: ms.spr.ly/6012TPE0C #NorthropGrumman #WSBW" (Tweet) – via Twitter.
- "EUTELSAT 5 West B/Mission Extension Vehicle-1". International Launch Services (ILS). 9 October 2019. Retrieved 30 January 2020.
MEV‑1 has the ability to dock and undock several times during its 15 year design life, allowing it to service multiple customers. SpaceLogistics' initial service, using the MEV‑1, will extend the life of the Intelsat 901 satellite for five years.
- "Ariane 5 launches Mission Extension Vehicle, two communications satellites to orbit". 14 August 2020. Retrieved 17 August 2020.
- de Selding, Peter B. (18 March 2011). "Intelsat Signs Up for MDA's Satellite Refueling Service". Space News. Archived from the original on 21 March 2012. Retrieved 20 March 2011.
more than 40 different types of fueling systems... SIS will be carrying enough tools to open 75% of the fueling systems aboard satellites now in geostationary orbit... the SIS spacecraft is designed to operate for seven years in orbit but that it is likely to be able to operate far longer than that. Key to the business model is MDA's ability to launch replacement fuel canisters that would be grappled by SIS and used to refuel dozens of satellites over a period of years. These canisters would be much lighter than the SIS vehicle and thus much less expensive to launch.
- "ATK: Introducing the expanded product line of agile spacecraft buses". Space News. 13 August 2012. pp. 16–17.
ATK A100 THEMIS; ATK A200 ORS-1, TacSat-3, and Earth Observing-1; ATK A500 DARPA Phoenix; ATK A700 ViviSat