The idea of using in-situ resources, such as water, on the surface of distant worlds to synthesize rocket fuel has been around for many decades.
For many years, for instance, scientists have suggested using frozen water on the Moon to ensure future space travelers have a way to make the journey back home.
Now, as Wired reports, former SpaceX engineer Halen Mattison and his startup, General Galactic, are looking to put the concept to the test once and for all.
The company is planning to launch a 1,100-pound satellite on a Falcon 9 rocket in October as part of an audacious proof of concept. The goal is to test water as the fuel for both electrical and chemical propulsion, processes that involve shooting out a stream of plasma with the use of a magnetic field and burning fuel at high temperature and pressure to generate thrust, respectively.
In the case of chemical propulsion, General Galactic is planning to split hydrogen and oxygen in the water via electrolysis, and then burn the hydrogen gas with oxygen as the oxidizer, as Wired explains. In a separate experiment, the company will turn oxygen generated by electrolysis into plasma by applying a strong electrical current.
It’s an ambitious plan that aims to show that water can be used for both short and steady “burps” of thrust in the case of electrical propulsion, and much more powerful but short-lived bursts of thrust in the case of chemical propulsion.
Mattison told Wired that the tech could be used to give military assets in space a much-needed boost. US satellites have already been found to be closely shadowed by Chinese and Russian ones, hinting at a future that could require satellites to defend themselves or flee danger in orbit.
But despite Mattison and his company’s optimism, relying on water for rocket propulsion is nowhere near a safe bet, and plenty of questions remain unanswered.
For instance, as General Galactic consultant and former NASA technologist Ryan Conversano told Wired, ionized oxygen could wreak havoc on the satellite’s electronics by corroding them.
“It makes material selection and design of the device or devices very, very challenging,” he said.
Using oxygen from water electrolysis could also lack an edge over more conventional chemical rocket fuels, especially when factoring in the mass of the electrolysis system itself.
In short, it’s no wonder scientists remain skeptical of the idea. But that doesn’t mean it’s not worth investigating.
For one, researchers are already hard at work to figure out how water and oxygen can be extracted from distant resources such as regolith on the Moon or Martian rocks.
Turning those resources into rocket fuel could prove immensely useful — particularly for any future space travelers unfortunate enough to have drained their spacecraft’s tanks ahead of their return.
More on rocket fuel: Chinese Astronauts Create Rocket Fuel in Space Using “Artificial Photosynthesis”