Project to develop a refueling ship right in orbit

The APS-R will provide refueling services to compatible vehicles in geostationary orbit at an altitude of approximately 35,800km above the equator.

There are thousands of satellites and spacecraft orbiting Earth, but they all face a serious problem: running out of fuel. This problem often causes satellites to stop working even when the equipment is still in good condition.

Simulation of the Astroscale Prototype Servicer for Refueling (APS-R) spacecraft in orbit. (Photo: Astroscale US).

To solve the fuel problem, the Southwest Research Institute (SwRI) in the US plans to develop spacecraft to provide space-based refueling services. This initiative is part of the $25.5 million Space Mobility and Logistics (SML) pilot project funded by the US Space Force and managed by aerospace company Astroscale US. They will develop a small spacecraft prototype called Astroscale Prototype Servicer for Refueling (APS-R) to refuel compatible vehicles in geostationary orbit.

Geostationary orbit satellites operate at an altitude of about 35,800 km above the equator. Most of them are used for telecommunications purposes. APS-R will move in a circular orbit that matches the Earth's rotation period. The ship will transport hydrazine propellant from storage to satellites that need the fuel. It can provide service to any spacecraft equipped with a compatible refueling port.

SwRI aims to build a "spaceship bus" to carry APS-R to space in the next 16 months. "The maximum dimensions are 61 x 71 x 114 cm when stowed for launch and the total launch mass of the vehicle is 198 kg, including propellant," said Steve Thompson, project engineer at SwRI.

^{Development of the spacecraft bus will take place at SwRI's new 6,900m 2} Spacecraft and Payload Processing Facility . This facility was built to quickly assemble and test small spacecraft.

Once the spacecraft bus design and development is complete, SwRI will integrate cargo provided by Astroscale and conduct environmental testing in preparation for launch. The APS-R ship is expected to be ready for launch in 2026 .