A Space Company Is Betting Its Future on Water as Propellant

A space company has staked its strategy on water as the propellant for its spacecraft. The choice runs against the grain of most propulsion designs, which favor denser and higher-performance fuels, but the company is wagering that water's easy availability will count for more than its performance limits.

The appeal is easy to see. Water is cheap, nontoxic and simple to handle on the ground, which avoids many of the costs and safety rules that come with hydrazine and other storable propellants. It is also stable at room temperature, so tanks and ground operations can be simpler. Over the longer term, water could become even more attractive if it can be drawn from ice on the Moon or on asteroids, which would let spacecraft refuel away from Earth.

The trade-off is performance. Water generally delivers less thrust per kilogram than conventional chemical options, which limits how much velocity change, or delta-V, a spacecraft can achieve on a given amount of fuel. The company will need to persuade mission planners that the extra mass is worth the savings in cost and handling, and that its propulsion system works reliably in flight.

The source item does not give details on the company's hardware, customers, funding or test results, so its claims should be treated as a starting point. Flight data and independent validation will be the real measures of whether water can carry the weight of this bet.