China's Shijian-25 satellite, launched on January 6, 2025, is testing orbital refueling operations. The mission includes docking with satellite Beidou-3 G7 and transferring 142 kilograms of hydrazine to extend its operational life by eight years.
Orbital refueling addresses the issue of satellites becoming space debris when their propellant depletes. The International Space Station (ISS) also requires periodic boosts to maintain altitude, typically using docked supply craft engines. DARPA's Orbital Express mission in 2007 demonstrated autonomous fuel transfers and component replacements.
Shijian-25 aims to demonstrate refueling in geosynchronous orbit, benefiting communications satellites. Challenges include precise rendezvous and leak prevention. Companies and space agencies are developing refueling systems to enhance sustainability and cost-effectiveness in space operations.