Southwest Research Institute (SwRI) will build, integrate and test a small demonstration spacecraft as part of a $25.5-million Space Mobility and Logistics (SML) prototyping project funded by the US Space Force and led by prime contractor Astroscale US. The spacecraft, called the Astroscale Prototype Servicer for Refueling (APS-R), will refuel other compatible vehicles while in geostationary orbit.

Southwest Research Institute (SwRI) will build, integrate and test a small demonstration spacecraft as part of a $25.5 million Space Mobility and Logistics (SML) prototyping project funded by the US Space Force and led by prime contractor Astroscale US. The spacecraft, called the Astroscale Prototype Servicer for Refueling (APS-R), will be able to refuel other vehicles while in geostationary orbit. Credit: Courtesy of Astroscale U.S.

Running low on fuel is a common issue for spacecraft in Earth orbit. When they have expended all of their fuel, their mission ends — even though the vehicle may be in otherwise excellent health. A refueling vehicle can extend those missions, and we can get additional lifetime out of spacecraft that are already in orbit.

—SwRI Staff Engineer Steve Thompson, the SwRI project systems engineer

The APS-R will operate in geostationary orbit around the Earth, meaning it will follow a circular orbit in sync with the Earth’s rotational period of 24 hours. The spacecraft will carry hydrazine propellant from a depot, also in geostationary orbit, to the spacecraft in need of fuel, rather than the client having to maneuver to a fuel depot, allowing client operations to continue uninterrupted. The APS-R can service any spacecraft fitted with a compatible refueling port (Orbit Fab).

Recently, other approaches to life extension have emerged, such as a vehicle that can use its thrusters to push another spacecraft where it needs to go after it runs out of fuel. A refueling vehicle broadens life extension options with a flexible alternative.

—Steve Thompson

Over the next 16 months, SwRI will construct the host vehicle for the APS-R in the Institute’s new 74,000-square-foot Space System Spacecraft and Payload Processing Facility, which was created to respond rapidly to customers needing to design, assemble and test spacecraft, particularly small satellites.

The maximum dimensions are 24-by-28-by-45 inches when stowed for launch, and the total vehicle launch mass is 437 pounds, including propellant.

—Steve Thompson

When the host spacecraft bus is complete, SwRI will integrate the Astroscale-supplied payload and perform system-level environmental testing to prepare the vehicle for launch. SwRI will deliver the launch-ready APS-R by 2026.