Orbital operations company Astroscale has revealed new details about its approach to refueling satellites in space, as part of a $25.5 million project with the Space Force to explore the concept. Their solution is a bit like a AAA truck traveling at 25,000 mph.
Many satellites are still functioning normally after years in space, but simply lack the fuel to safely maintain their designated altitudes and orbits, so they must be deorbited. Operators could choose to launch another satellite worth $100 million, or, as companies such as Astroscale and OrbitFab have suggested, spend a tenth of the cost to do a gas refill from the surface to geostationary orbit.
Of course, most satellites are not designed to be refueled, but that could easily be changed -- though how that would be done is an open question. Last summer, Astroscale won a Space Force contract to explore this possibility in orbit.
The Astronomical Scale Prototype Refueling Server (APS-R) is a small satellite (interestingly, about the same size as a gas pump on Earth) that will ascend to geostationary orbit - approximately 300 kilometers above sea level - and then fly to a "ready customer" with the correct refueling port. (This customer is still an "e.g." in the picture, so there are no formal plans yet).
After refueling the customer satellite, APS-R will back off and inspect the customer satellite, looking for fuel leaks or other issues that the operator may need to inspect. It will then ascend again to Geosynchronous Orbit+ and rendezvous with the Defense Innovation Unit's RAPIDS fuel depot.
Some other space-based refueling concepts have chosen the relatively simple approach of keeping all fuel on the spacecraft itself, rather than acting as an emergency shuttle between the space station and the customer (hence the AAA comparison). But since the military seems to believe that a giant, geostationary pressure vessel filled with hydrazine is a safer option, Astroscale intends to adopt this approach, and there may be a non-military independent version later.
The joint project - which is essentially split down the middle from a cost perspective - is only at the "operational concept" stage, but Astroscale expects to deliver it by 2026. No doubt we'll be hearing more about this and other space sustainability projects before then.