Orbiting 'Rest Stops' Could Repair Crumbling Satellites

astroengine writes: Satellites are numerous, vital to many modern activities, and incredibly expensive to build and launch. They're constructed with redundancy and simplicity in mind because if something goes wrong after the satellite reaches orbit, we can't do much to help it. Now, NASA is talking about building an orbital service station that can perform maintenance, repair, and even refueling operations on these satellites. "Is there a way working with humans and robots together to extend the useful life of satellites, by fixing them and by not allowing fuel to spill out, but give it more propellant, close it up and send it on its way?," said Benjamin Reed, deputy director of the Satellite Servicing Program Office at NASA's Goddard Space Flight Center. "Yes, We have the technologies to be able to do it."

Comments

Tug boats

[Immerman]

Of course, the "rest stops" with their stockpiles of fuel and parts will probably be massive structures, so we'll also need "tug boats" to transfer the satellites from their original orbit to one that can dock with the rest stop, and then return it to it's designated orbit again after repair and refueling. Still far less energy-intensive than sending up a replacement satellite though. And if only refueling is needed then it's probably easier still to outfit the tug with a refueling waldo that can mate with a standardized fuel receptacle on the satellite - then the tug only has to make a single trip from the rest stop/fuel depo to whatever wonky orbit the satellite is in, and the satellite itself need never move at all.

Orbital mechanics

[Dan East]

The huge problem is orbital mechanics. The delta-V difference between satellites is enormous. Polar orbit, geosynchronous orbit, low-earth orbit, etc, etc. The difference in velocity between them is more than any satellite or service vehicle could realistically overcome (assuming you want to visit more than one satellite every couple decades). Satellites in geostationary orbit might be doable, because they all have to orbit relative to the earth's rotation, so traversing from one to another might be reasonable. However they are so far up there that it would still require covering a lot of distance to get from one to another.