Space Infrastructure Servicing
Encyclopedia
Space Infrastructure Servicing (SIS) is a spacecraft
being developed by Canadian
aerospace firm MacDonald, Dettwiler and Associates to operate as a small-scale in-space refueling depot
for communication satellites in geosynchronous orbit
. Intelsat
is a requirements
and funding
partner for the initial demonstration satellite which, , was planned to be launched in approximately 2015.
MDA put the launch plans on hold in November 2011 pending finding a second launch partner, beyond Intellsat.
project was under development. The design point was to be a single spacecraft that would refuel other spacecraft in orbit as a satellite-servicing demonstration. The 2010 announcement indicated that MDA had already signed an option agreement
"with an unidentified satellite fleet operator that has agreed to provide an aging telecommunications spacecraft for a refueling operation as the inaugural customer." Missions contemplated included not only satellite refueling but also space debris mitigation by including the vehicle capability to "push dead satellites into graveyard orbits."
The early technical design point included a fuel-depot vehicle that would maneuver
to an operational communications satellite
, dock at the target satellite’s apogee-kick motor
, remove a small part of the target spacecraft’s thermal protection blanket
, connect to a fuel-pressure line and deliver the propellant
. In 2010, it was estimated that "the docking maneuver would take the communications satellite out of service for about 20 minutes."
A potential business model
for the service, , would "ask customers to pay per kilogram of fuel successfully added to their satellite, with the per-kilogram price being a function of the additional revenue the operator can expect to generate from the spacecraft’s extended operational life."
In March 2011, MDA announced that Intelsat
was to be their inaugural launch partner and that the SIS vehicle could be ready to launch as early as 2015, with Intelsat providing up to over the timeframe that the on-orbit services would be delivered to a portion of the Intelsat satellite fleet.
, MDA suspended the satellite servicing mission while awaiting major decisions due soon on the scope and details on planned satellite servicing missions by US government civilian and defence agencies NASA
and DARPA. MDA wants to "see the NASA and DARPA bid requests, see what’s in them, whether [MDA] can bid as a Canadian company, or as a U.S. company."
MDA Chief Executive Officer Daniel E. Friedmann
said "We can’t just go ahead. I know everybody says the government is not a competitor, and yes, literally they are not a competitor. But our whole business is about winning business from the government and then taking that dual-use technology into the commercial market."
has agreed to purchase one-half of the 2000 kilograms (4,409.2 lb) propellant payload that the MDA spacecraft would carry into geostationary orbit
. Such a purchase would add somewhere between two and four years of additional service life for up to five Intelsat satellites, assuming 200 kg of fuel is delivered to each one.
SIS will carry a toolkit designed to open most of the approximately 40 types of "fueling systems aboard satellites now in geostationary orbit."
to rendezvous
with a replacement fuel canister after deploying the of fuel in the first load, enabling the further refueling of additional satellites after the initial multi-satellite servicing mission is complete.
design alternatives to in-space RCS
fuel transfer exist. The ViviSat Mission Extension Vehicle
illustrates one alternative approach that would connect to the target satellite in a similar way as MDA SIS, via the kick motor, but will not transfer fuel. Rather, ViviSat will use "its own thrusters to supply attitude control for the target."
ViviSat believes their approach is simpler and can operate at lower cost than MDA, while having the technical ability to dock with a greater number (90 percent) of the approximately 450 geostationary
satellites in orbit.
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
being developed by Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
aerospace firm MacDonald, Dettwiler and Associates to operate as a small-scale in-space refueling depot
Propellant depot
An orbital propellant depot is a cache of propellant that is placed on an orbit about the Earth or another body to allow spacecraft to be fuelled in space. Launching a spacecraft separately from some of its propellant enables missions with more massive payloads...
for communication satellites in geosynchronous orbit
Geosynchronous orbit
A geosynchronous orbit is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period...
. Intelsat
Intelsat
Intelsat, Ltd. is a communications satellite services provider.Originally formed as International Telecommunications Satellite Organization , it was—from 1964 to 2001—an intergovernmental consortium owning and managing a constellation of communications satellites providing international broadcast...
is a requirements
Product requirements document
A product requirements document is a document written by a company that defines a product they are making, or the requirements for one or more new features for an existing product...
and funding
Project finance
Project finance is the long term financing of infrastructure and industrial projects based upon the projected cash flows of the project rather than the balance sheets of the project sponsors...
partner for the initial demonstration satellite which, , was planned to be launched in approximately 2015.
MDA put the launch plans on hold in November 2011 pending finding a second launch partner, beyond Intellsat.
History
MDA Corporation announced in early 2010 that a small-scale geosynchronous-orbit refuelingPropellant depot
An orbital propellant depot is a cache of propellant that is placed on an orbit about the Earth or another body to allow spacecraft to be fuelled in space. Launching a spacecraft separately from some of its propellant enables missions with more massive payloads...
project was under development. The design point was to be a single spacecraft that would refuel other spacecraft in orbit as a satellite-servicing demonstration. The 2010 announcement indicated that MDA had already signed an option agreement
Option (finance)
In finance, an option is a derivative financial instrument that specifies a contract between two parties for a future transaction on an asset at a reference price. The buyer of the option gains the right, but not the obligation, to engage in that transaction, while the seller incurs the...
"with an unidentified satellite fleet operator that has agreed to provide an aging telecommunications spacecraft for a refueling operation as the inaugural customer." Missions contemplated included not only satellite refueling but also space debris mitigation by including the vehicle capability to "push dead satellites into graveyard orbits."
The early technical design point included a fuel-depot vehicle that would maneuver
Orbital maneuver
In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft.For spacecraft far from Earth—for example those in orbits around the Sun—an orbital maneuver is called a deep-space maneuver .-delta-v:...
to an operational communications satellite
Communications satellite
A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
, dock at the target satellite’s apogee-kick motor
Apogee kick motor
An apogee kick motor refers to a rocket motor that is regularly employed on artificial satellites destined for a geostationary orbit. As the vast majority of geostationary satellite launches are carried out from spaceports at a significant distance away from Earth's equator, the carrier rocket...
, remove a small part of the target spacecraft’s thermal protection blanket
Multi-layer insulation
Multi-layer insulation, or MLI, is thermal insulation composed of multiple layers of thin sheets often used on spacecraft. It one of the main items of the spacecraft thermal design, mainly intended to reduce heat loss by thermal radiation. In its basic form, it does not appreciably insulate...
, connect to a fuel-pressure line and deliver the propellant
Rocket propellant
Rocket propellant is mass that is stored in some form of propellant tank, prior to being used as the propulsive mass that is ejected from a rocket engine in the form of a fluid jet to produce thrust. A fuel propellant is often burned with an oxidizer propellant to produce large volumes of very hot...
. In 2010, it was estimated that "the docking maneuver would take the communications satellite out of service for about 20 minutes."
A potential business model
Business model
A business model describes the rationale of how an organization creates, delivers, and captures value...
for the service, , would "ask customers to pay per kilogram of fuel successfully added to their satellite, with the per-kilogram price being a function of the additional revenue the operator can expect to generate from the spacecraft’s extended operational life."
In March 2011, MDA announced that Intelsat
Intelsat
Intelsat, Ltd. is a communications satellite services provider.Originally formed as International Telecommunications Satellite Organization , it was—from 1964 to 2001—an intergovernmental consortium owning and managing a constellation of communications satellites providing international broadcast...
was to be their inaugural launch partner and that the SIS vehicle could be ready to launch as early as 2015, with Intelsat providing up to over the timeframe that the on-orbit services would be delivered to a portion of the Intelsat satellite fleet.
, MDA suspended the satellite servicing mission while awaiting major decisions due soon on the scope and details on planned satellite servicing missions by US government civilian and defence agencies NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
and DARPA. MDA wants to "see the NASA and DARPA bid requests, see what’s in them, whether [MDA] can bid as a Canadian company, or as a U.S. company."
MDA Chief Executive Officer Daniel E. Friedmann
Daniel Friedmann
Daniel Friedmann was the Minister of Justice of Israel from 2007 to 2009. A professor of law, he was appointed by PM Ehud Olmert. He was sworn in on February 7, 2007, succeeding Tzipi Livni. In 2009 he was succeeded by Ya'akov Ne'eman.-Early life:...
said "We can’t just go ahead. I know everybody says the government is not a competitor, and yes, literally they are not a competitor. But our whole business is about winning business from the government and then taking that dual-use technology into the commercial market."
In-space refueling demonstration project
, MDA has secured its first major customer for the initial demonstration project. IntelsatIntelsat
Intelsat, Ltd. is a communications satellite services provider.Originally formed as International Telecommunications Satellite Organization , it was—from 1964 to 2001—an intergovernmental consortium owning and managing a constellation of communications satellites providing international broadcast...
has agreed to purchase one-half of the 2000 kilograms (4,409.2 lb) propellant payload that the MDA spacecraft would carry into geostationary orbit
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
. Such a purchase would add somewhere between two and four years of additional service life for up to five Intelsat satellites, assuming 200 kg of fuel is delivered to each one.
SIS will carry a toolkit designed to open most of the approximately 40 types of "fueling systems aboard satellites now in geostationary orbit."
Technical details
The servicing of the initial satellite on the demonstration mission will be accomplished as follows:- "Intelsat will select one of its satellites nearing retirement to be moved into a standard graveyard orbitGraveyard orbitA graveyard orbit, also called a supersynchronous orbit, junk orbit or disposal orbit, is an orbit significantly above synchronous orbit, where spacecraft are intentionally placed at the end of their operational life...
some 200 to 300 kilometers above the geostationary arc 36,000 kilometers over the equator." - MDA will "launch the SIS servicer, which will rendezvous and dock with the Intelsat satellite, attaching itself to the ring around the satellite’s apogee-boost motorApogee kick motorAn apogee kick motor refers to a rocket motor that is regularly employed on artificial satellites destined for a geostationary orbit. As the vast majority of geostationary satellite launches are carried out from spaceports at a significant distance away from Earth's equator, the carrier rocket...
." - Controlled from a ground stationTeleoperationTeleoperation indicates operation of a machine at a distance. It is similar in meaning to the phrase "remote control" but is usually encountered in research, academic and technical environments...
, "the SIS robotic arm will reach through the nozzle of the apogee motor to find and unscrew the satellite’s fuel cap." - "the SIS vehicle will reclose the fuel cap after delivering the agreed amount of propellant and then head to its next mission."
Post-demonstration mission extension
In addition to refueling and servicing geostationary comm sats with the fuel that is initially launched with the vehicle, the SIS vehicle is being designed to have the ability to orbitally maneuverOrbital maneuver
In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft.For spacecraft far from Earth—for example those in orbits around the Sun—an orbital maneuver is called a deep-space maneuver .-delta-v:...
to rendezvous
Space rendezvous
A space rendezvous is an orbital maneuver during which two spacecraft, one of which is often a space station, arrive at the same orbit and approach to a very close distance . Rendezvous requires a precise match of the orbital velocities of the two spacecraft, allowing them to remain at a constant...
with a replacement fuel canister after deploying the of fuel in the first load, enabling the further refueling of additional satellites after the initial multi-satellite servicing mission is complete.
Competitive approaches
CompetitiveCompetition
Competition is a contest between individuals, groups, animals, etc. for territory, a niche, or a location of resources. It arises whenever two and only two strive for a goal which cannot be shared. Competition occurs naturally between living organisms which co-exist in the same environment. For...
design alternatives to in-space RCS
Reaction control system
A reaction control system is a subsystem of a spacecraft whose purpose is attitude control and steering by the use of thrusters. An RCS system is capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS is also capable of providing torque to allow...
fuel transfer exist. The ViviSat Mission Extension Vehicle
Mission Extension Vehicle
The Mission Extension Vehicle is a spacecraft concept proposed by ViviSat, a 50/50 joint venture of aerospace firms U.S. Space and ATK, to operate as a small-scale in-space satellite-refueling spacecraft.-Technical capabilities and competition:...
illustrates one alternative approach that would connect to the target satellite in a similar way as MDA SIS, via the kick motor, but will not transfer fuel. Rather, ViviSat will use "its own thrusters to supply attitude control for the target."
ViviSat believes their approach is simpler and can operate at lower cost than MDA, while having the technical ability to dock with a greater number (90 percent) of the approximately 450 geostationary
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
satellites in orbit.
See also
- Orbital ExpressOrbital Expressthumb|Orbital Express: ASTRO and NEXTSatOrbital Express was a space mission managed by the United States Defense Advanced Research Projects Agency and a team led by engineers at NASA's Marshall Space Flight Center...
— a 2007 U.S. government-sponsored mission to test in-space satellite servicing with two vehicles designed from the start for on-orbit refueling and subsystem replacement.