Space Infrastructure Servicing

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, as of March 2011, was planned to be launched in approximately 2015.[1][2] MDA put the launch plans on hold in November 2011 pending finding a second launch partner, beyond Intellsat.[3]

Contents

History

MDA Corporation announced in early 2010 that a small-scale geosynchronous-orbit refueling 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."[4] Missions contemplated included not only satellite refueling but also space debris mitigation by including the vehicle capability to "push dead satellites into graveyard orbits."[4]

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."[4]

A potential business model for the service, as of March 2010, 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."[4]

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 US$280,000,000 over the timeframe that the on-orbit services would be delivered to a portion of the Intelsat satellite fleet.[1]

As of November 2011, 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."[3] 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."[3]

In-space refueling demonstration project

As of March 2011, MDA has secured its first major customer for the initial demonstration project. Intelsat has agreed to purchase one-half of the 2,000 kilograms (4,400 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.[2]

SIS will carry a toolkit designed to open most of the approximately 40 types of "fueling systems aboard satellites now in geostationary orbit."[5]

Technical details

The servicing of the initial satellite on the demonstration mission will be accomplished as follows:[5]

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 maneuver to rendezvous with a replacement fuel canister after deploying the 2000 kg of fuel in the first load, enabling the further refueling of additional satellites after the initial multi-satellite servicing mission is complete.[5]

Competitive approaches

Competitive 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."[6] 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.[6]

See also

References

  1. ^ a b "Intelsat Picks MacDonald, Dettwiler and Associates Ltd. for Satellite Servicing". press release. CNW Group. http://www.canadanewswire.ca/en/releases/archive/March2011/15/c2866.html. Retrieved 2011-03-15. "MDA plans to launch its Space Infrastructure Servicing ("SIS") vehicle into near geosynchronous orbit, where it will service commercial and government satellites in need of additional fuel, re-positioning or other maintenance. ... MDA and Intelsat will work together to finalize specifications and other requirements over the next six months before both parties authorize the build phase of the program. The first refueling mission is to be available 3.5 years following the commencement of the build phase. ... The services provided by MDA to Intelsat under this agreement are valued at more than US$280 million." 
  2. ^ a b de Selding, Peter B. (2011-03-14). "Intelsat Signs Up for Satellite Refueling Service". Space News. http://www.spacenews.com/satellite_telecom/intelsat-signs-for-satellite-refueling-service.html. Retrieved 2011-03-15. "if the MDA spacecraft performs as planned, Intelsat will be paying a total of some $200 million to MDA. This assumes that four or five satellites are given around 200 kilograms each of fuel. ... The maiden flight of the vehicle would be on an International Launch Services Proton rocket, industry officials said. One official said the MDA spacecraft, including its 2,000 kilograms of refueling propellant, is likely to weigh around 6,000 kilograms at launch." 
  3. ^ a b c de Selding, Peter (2011-11-01). "MDA Puts Satellite Servicing on Hold; Reports Core Businesses Doing Well". Space News. http://spacenews.com/contracts/110111-mda-puts-satellite-servicing-hold-reports-core-businesses-doing-well.html. Retrieved 2011-11-05. 
  4. ^ a b c d de Selding, Peter B. (2010-03-03). "MDA Designing In-orbit Servicing Spacecraft". Space News. http://spacenews.com/satellite_telecom/100303-mda-planning-inorbit-servicing-demo.html. Retrieved 2011-03-14. "MDA has signed an option with an unidentified satellite fleet operator that has agreed to provide an aging telecommunications spacecraft for a refueling operation as the inaugural customer ... the refueling vehicle would dock at the target satellite’s apogee-kick motor, peel off a section of the craft’s thermal protection blanket, connect to a fuel-pressure line and deliver the propellant. MDA officials estimate the docking maneuver would take the communications satellite out of service for about 20 minutes. ... The servicing robot would have an in-orbit life of about five years, and would carry enough fuel to perform 10 or 11 satellite-refueling or orbital-cleanup missions." 
  5. ^ a b c de Selding, Peter B. (2011-03-18). "Intelsat Signs Up for MDA’s Satellite Refueling Service". Space News. http://www.sbv.spacenews.com/satellite_telecom/110318intelsat-signs-for-mdas-satellite-refueling-service.html. Retrieved 2011-03-20. "more than 40 different types of fueling systems ... SIS will be carrying enough tools to open 75 percent 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. " 
  6. ^ a b Morring, Frank, Jr. (2011-03-22). "An End To Space Trash?". Aviation Week. http://www.aviationweek.com/aw/generic/story.jsp?id=news/awst/2011/03/21/AW_03_21_2011_p23-297586.xml&headline=An%20End%20to%20Space%20Trash?&channel=awst. Retrieved 2011-03-21. "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." 

External links