The Mission Extension Vehicle (MEV) [1] 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. [2]
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. [3] 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 [3] 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. [4]
ViviSat proposed the Mission Extension Vehicle (MEV) concept in 2011. [1] 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. [2] 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, [5] but had announced no customers for the Mission Extension Vehicle services. [5]
In April 2014, ATK announced that it would merge its Aerospace and Defense Groups with Orbital Sciences Corporation. [6]
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. [3]
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. [7] [8] 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. [8]
In 2018, Orbital ATK was acquired by Northrop Grumman to become Northrop Grumman Innovation Systems. The MEV program continues under this new company.
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. [9] MEV-1 was launched on 9 October 2019. [10]
MEV-1 rendezvoused with Intelsat 901 on 25 February 2020 at 07:15 UTC, [11] [12] and by April 2020 had repositioned the commsat so that it could come back on line in its designated geosynchronous spot, [13] 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. [4] The goal is to extend its operational life by five years via in-orbit stationkeeping. [14] [15] 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. [16]
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"., [2] 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, [5] 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", [2] whereas MDA SIS could open and refuel only 75%. [20]
"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". [2]
As of 2012 [update] , ViviSat planned to use the ATK A700 satellite bus. [21]
Intelsat S.A. is a multinational satellite services provider with corporate headquarters in Luxembourg and administrative headquarters in Tysons Corner, Virginia, United States. Originally formed as International Telecommunications Satellite Organization, from 1964 to 2001, it was an intergovernmental consortium owning and managing a constellation of communications satellites providing international telecommunications and broadcast services.
Orbital Sciences Corporation was an American company specializing in the design, manufacture, and launch of small- and medium- class space and launch vehicle systems for commercial, military and other government customers. In 2014, Orbital merged with Alliant Techsystems to create a new company called Orbital ATK, Inc., which in turn was purchased by Northrop Grumman in 2018. The remnants of the former Orbital Sciences Corporation became a subsidiary of Northrop Grumman, known as Northrop Grumman Space Systems.
An orbital propellant depot is a cache of propellant that is placed in orbit around Earth or another body to allow spacecraft or the transfer stage of the spacecraft to be fueled in space. It is one of the types of space resource depots that have been proposed for enabling infrastructure-based space exploration. Many different depot concepts exist depending on the type of fuel to be supplied, location, or type of depot which may also include a propellant tanker that delivers a single load to a spacecraft at a specified orbital location and then departs. In-space fuel depots are not necessarily located near or at a space station.
Docking and berthing of spacecraft is the joining of two space vehicles. This connection can be temporary, or partially permanent such as for space station modules.
Space Infrastructure Servicing (SIS) is a spacecraft concept being developed by Canadian aerospace firm MDA to operate as a small-scale in-space refueling depot for communication satellites in geosynchronous orbit.
A space tug is a type of spacecraft used to transfer spaceborne cargo from one orbit to another orbit with different energy characteristics. The term can include expendable upper stages or spacecraft that are not necessarily a part of their launch vehicle. However, it can also refer to a spacecraft that transports payload already in space to another location in outer space, such as in the Space Transportation System concept. An example would be moving a spacecraft from a low Earth orbit (LEO) to a higher-energy orbit like a geostationary transfer orbit, a lunar transfer, or an escape trajectory.
On-orbit satellite servicing refers to refueling or repairing space satellites while in orbit.
NG-10, previously known as OA-10E, is the eleventh flight of the Northrop Grumman uncrewed resupply spacecraft Cygnus and its tenth flight to the International Space Station under the Commercial Resupply Services (CRS-1) contract with NASA. The mission launched on 17 November 2018, at 09:01:31 UTC. This particular mission is part of an extension of the initial CRS contract that enables NASA to cover the ISS resupply needs until the Commercial Resupply Services-2 (CRS-2) contract enters in effect.
NG-11, previously known as OA-11, is the twelfth flight of the Northrop Grumman robotic resupply spacecraft Cygnus and its eleventh flight to the International Space Station under the Commercial Resupply Services (CRS-1) contract with NASA. The mission launched on 17 April 2019 at 20:46:07 UTC. This is the last mission from the extended CRS-1 contract; follow-up missions are part of the CRS-2 contract. Cygnus NG-11 was also the first mission to load critical hardware onto Cygnus within the last 24 hours prior to launch, a new Antares feature.
The GEOStar is a family of satellite buses designed and manufactured by Northrop Grumman Innovation Systems. The family started focused on small geostationary communications satellites. The first iterations focused on the sub-5 kW commercial segment that was left vacated after the retirement of the HS-376 satellite bus. It started with the STARBus on CTA Space Systems, which was later bought successively by Orbital Sciences, Orbital ATK, and most recently Northrop Grumman Innovation Systems.
Intelsat 10-02 is a communications satellite operated by Intelsat. Intelsat 10-02 is the first operational communications satellite to have its service life extended by Mission Extension Vehicle-2, while still in service, in 2021.
Intelsat 907 was a communications satellite operated by Intelsat.
Eutelsat 5 West B is a geostationary communications satellite. It is owned by European satellite communications company Eutelsat. It launched on October 9, 2019, at 10:17 UTC on a Proton-M rocket from Baikonur Cosmodrome in Kazakhstan. The satellite was built by Northrop Grumman and Airbus Defence and Space and has an expected operational life of more than 15 years. Situated at 5° west, it broadcasts satellite television, radio and other digital data. It was scheduled to enter operational service at the end of 2019, but deployment difficulties delayed service.
NG-15, previously known as OA-15, was the fifteenth launch of the Northrop Grumman robotic resupply spacecraft Cygnus and its fourteenth flight to the International Space Station (ISS) under the Commercial Resupply Services (CRS) contract with NASA. The mission launched on 20 February 2021 at 17:36:50 UTC. This is the fourth launch of Cygnus under the CRS-2 contract.
Cygnus NG-16, previously known as Cygnus OA-16, was the sixteenth flight of the Northrop Grumman robotic resupply spacecraft Cygnus and its fifteenth flight to the International Space Station (ISS) under the Commercial Resupply Services (CRS-2) contract with NASA. The mission was launched on 10 August 2021 at 22:01:05 UTC, for a (planned) 90-day mission at the ISS. This was the fifth launch of Cygnus under the CRS-2 contract.
NG-18 was the eighteenth flight of the Northrop Grumman robotic resupply spacecraft Cygnus and its seventeenth flight to the International Space Station (ISS) under the Commercial Resupply Services (CRS-2) contract with NASA. The mission successfully launched on 7 November 2022 at 10:32:42 UTC. This was the seventh launch of Cygnus under the CRS-2 contract.
Satellite refuelling is the operation of replenishing on board propellants and other consumables in satellites in orbit, e.g. in geostationary orbit around Earth.
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.
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.
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 A100 THEMIS; ATK A200 ORS-1, TacSat-3, and Earth Observing-1; ATK A500 DARPA Phoenix; ATK A700 ViviSat
