Fuel is the lifeblood of any satellite. Without it, even the most capable craft cannot stay in its designated orbit and will slowly drift off course or fall back toward Earth. Losing a valuable satellite for want of propellant is a painful reminder of how critical efficient logistics are in space operations.
Last year saw the emergence of a concept often described as a space-based refueling network or a moving fuel station. The Tenjin space tanker, developed by an American startup, approaches satellites that have exhausted their fuel, docks with them, and transfers propellant. It is like a road-side fuel stop, but the station itself travels through space to meet its customer, enabling a wider range of missions and longer service lives for orbiting assets.
The first vessel in this program, Tanker 001 Tenjin, was produced by Orbit Fab and launched in June of the previous year aboard a Falcon 9 rocket from Florida. This compact unit weighs 35 kilograms and is designed to operate in low Earth orbit at altitudes roughly between 518 and 544 kilometers. Its target is a fellow satellite gliding along the same orbital path at roughly 7.5 kilometers per second. Tanker 001 Tenjin uses a stereo imaging system to identify its companion, aligns with the same flight corridor, and completes a precise pass to establish a refueling rendezvous. The process relies on exacting navigation and synchronized maneuvering to ensure a safe and effective transfer of propellant.
Central to Tenjin’s approach is a compact RAFTI tank unit. The core idea is compatibility with other satellites that share the same platform, enabling docking and refueling when conditions permit. The device itself measures only 75 millimeters in diameter, underscoring the need for exceptional precision in guidance, alignment, and proximity operations. In practice, successful refueling depends on predictable orbital dynamics and highly reliable control systems, along with careful coordination with the target spacecraft.
Tanker 002 Tenjin
The second tanker, Tanker 002 Tenjin, features enhancements based on early operations and will carry around 90 kilograms of propellant. It is scheduled to launch in conjunction with an upcoming lunar mission. After deployment, it will establish a presence in a geostationary orbit at about 35,786 kilometers altitude. In this layer of space, satellites can appear fixed relative to the Earth as the planet rotates underneath them. This region hosts a broad mix of critical assets, including Earth observation, communications, broadcast systems, and some military platforms. A notable portion of satellites in this zone carries propellant for active missions, but many have reached a propellant-depleted state and await a refill opportunity. The trajectory of Tanker 002 Tenjin is designed to support extended lifetimes and greater mission flexibility for space operators in North American and allied markets. (Source attribution: Orbit Fab)