American startup General Galactic, founded by ex-SpaceX engineer Galen Mattison and ex-Varda Space engineer Luke Nyse, preparing the Trinity demonstration mission. The company plans to launch a satellite with a mass close to 500 kg on a joint Falcon launch 9 in October 2026 year, to prove, that water can be the only working body for maneuvers in orbit.
The key idea of Trinity is to test two methods of water draft at once. For the chemical scheme, water is decomposed into hydrogen and oxygen by electrolysis, after which the hydrogen is burned, using oxygen as an oxidant. For electric, water is also split, and then provide sufficient energy, to turn oxygen into plasma, which is directed from the engine by a magnetic field, getting traction.
The developers emphasize that, that water is easier and safer to use, than cryogenic components such as methane — it does not need to be kept at extremely low temperatures and there is no problem of the fuel boiling away from heating by the Sun. The company also claims the potential for a 5-10x higher Δv margin compared to traditional systems, which is important for quick evasions and active maneuvers in crowded orbital zones.
For reference: stock Δv (delta v) is the total change in velocity, which the spacecraft can provide with the help of its engines (fuel) to perform maneuvers. It determines the potential of the apparatus to change the orbit, adjusting the trajectory or landing, and is a key indicator of the mission's energy capabilities.
Water can theoretically be extracted from ice on the Moon or other bodies, and then convert into fuel components. NASA has long considered using lunar ice for oxygen/fuel, and small water engines have already been tested in orbit (in particular, the Japanese Pale Blue). If General Galactic's approach is confirmed on a larger vehicle, it can make it cheaper to power satellites and extend the life of scientific platforms — from orbital observatories to instruments at Lagrange points, which require regular orbit corrections and the ability to quickly change observation configurations.
Source: https://universemagazine.com