Sunday, April 03, 2011

A Backgrounder for On-Orbit Satellite Servicing

As outlined in my July 21, 2009 post titled "Even Werner von Braun was Wrong Once in a While...," the driving personality behind our first great space race once laid out a plan to send men to the Moon and Mars, using reusable spacecraft and a space station big enough to sustain and pay for itself with enough extra repair/ refueling capacity to construct a lunar and planetary expedition fleet for further exploration.



Unfortunately for the plan, printed circuits superseded the fragile and short-lived vacuum tube used in the 1950's and we were suddenly able to build much more durable and capable satellites for a fraction of the cost of a manned station.

MDA Space Infrastructure Servicing (SIS). 
So we ended up getting the weather, communications and surveillance capabilities (plus several much smaller but nowhere near self sufficient manned space stations like Salyut, Almaz, Skylab and MIR) but not the extra capacity needed to construct the promised interplanetary fleet.

This state of affairs might just be in the midst of changing with the March 14th, 2011 announcement by BC based MacDonald Dettwiler (MDA) of a $280 million USD agreement with satellite operator Intelesat for the servicing of Intelsat's on-orbit satellites via a space-based service vehicle to be provided by MDA ("Intelsat Picks MacDonald, Dettwiler and Associates Ltd. for Satellite Servicing").

The importance of this announcement flows from the simple fact that once a system is in place to refuel, service and repair satellites it's not much of a stretch for the system to be upgraded and modified to the point where it's capable of refueling and repairing pretty much anything made by man, pretty much anywhere in space.

And from there, it's only another short hop to actually being able to build things like interplanetary spacecraft in orbit, pretty much the very same way that Werner von Braun once envisioned.

Even better, the present MDA on-orbit satellite servicing and refueling proposal is a follow-on to the existing MDA CanadArm program. The CanadArm is essentially just a big orbiting space crane designed for the construction of the International Space Station (ISS), although it's also helpful for expediting the ISS docking process, which is what the CanadArm2 does now for the Japan Aerospace eXploration Agency (JAXA) Kounotori 2 and plans to do with the Orbital Sciences Corporation (Orbital) designed Cygnus cargo delivery spacecraft.

Intelesat Galaxy 15.
Of course, there are certainly hurdles and difficulties still to be overcome before the MDA plan can move forward. Some of those concerns were outlined in the March 16th,  2011 Space.com article "Satellite Builders Not Enthusiastic About In-orbit Servicing Project" which mentioned legal issues, questions concerning time to profitability and whether or not the application would be more suitable for higher-value institutional satellites rather than the commercial satellite market as represented by the present prime contractor Intelesat.

The agreement between MDA and Intelsat is still to be finalized and there is a six month window before the final decision to move forward will be made. The first refueling mission should be available 3.5 years after this concluding contract is signed.

But it's also worth noting that, on average, one satellite in geosynchronous orbit is going to fail each year, according to the September 2010 Milsat Magazine article "Intel... Zombiesat's and On-Orbit Servicing". On April 8th, 2010, Intelesat lost contact with Galaxy 15, one of its approximately 50 geosynchronous satellites and contact was re-established only with difficulty after the satellite had caused considerable hazard to other orbital objects.

So there is indeed a market for this sort of service. Satellites often break and need to be fixed.

MDA is not alone in making recent proposals in this area although it seems so far unique in snagging an actual contract from a satellite operator.

But the advantages to possessing this capability are many.

For example, a team working out of Georgia Institute of Technology has released a study (titled "Near Term Space Exploration with Commercial Launch Vehicles Plus Propellant Depot") looking at what happens to program costs if you add propellant depots (similar to those planned as part of the MDA proposal) to the National Aeronautics and Space Administration (NASA) Human Exploration Framework Team (HEFT) baseline proposal study on what it would take to do a twenty-year human exploration program culminating in human flights to near-Earth asteroids.

The comparison is illuminating. According to this March 30th, 2011 post on the Hobbyspace website:
The HEFT study (Human Exploration Framework Team) concluded that if NASA built its own 100-ton payload Heavy Lift booster then used it to launch fully-fueled mission stages Apollo-style, the overall program cost would be $143 billion over twenty years, or an average of just over seven billion a year. For what it's worth, NASA Human Exploration looks likely to be funded at no more than four to five billion a year for the foreseeable future.

Now a team working out of Georgia Tech has released a study looking at what happens to program costs if you add propellant depots to the HEFT baseline, allowing everything to be launched on medium-lift commercial launch vehicles with no need for a new NASA SLS-style HLV...

...Under a range of assumptions, their cost for this modified HEFT program comes in at between $73 billion and $97 billion over twenty years - an average of between $3.6 billion and $4.9 billion per year.

These studies make it crystal clear: NASA can probably afford a human deep-space exploration program based on commercial boosters plus propellant depots. NASA definitely cannot afford a human deep-space exploration program based on the Congressionally-mandated 130-ton SLS heavy lifter.
Expect the applications from this technology and servicing capability to begin to grow exponentially over the next few years, as other organizations realize some of the obvious and immediate advantages accruing to organizations like MDA, who possess this capability.

Werner von Braun would be pleased.

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