This space company is betting its future on a propellant available everywhere
The idea of using water as propellant has been kicking around for a while, but the fact that a company is now betting its whole future on it tells you the economics might finally be shifting. Water is heavy, but it's also everywhere in the solar system, at least in theory. If you can mine it on the Moon or Mars, you don't have to hoist every kilogram of fuel out of Earth's gravity well, and that changes the math on long missions in a fundamental way.
What I'd want to know is the efficiency story. Splitting water into hydrogen and oxygen for a chemical engine gives you decent thrust but not great specific impulse. Electric propulsion can stretch it further, but then you're trading time for fuel. The company's pitch likely hinges on which trade-off they've picked, and that's the detail that matters most.
There's also the storage problem. Water freezes in space unless you keep it warm, and managing that adds mass and complexity. Plenty of promising propulsion concepts have died on exactly that kind of practical detail. I'm curious whether they've solved it or are still hand-waving past it.
I land somewhere between intrigued and cautious. The concept is sound, but the history of space propulsion is littered with elegant ideas that couldn't survive contact with real missions. I'd want to see a test article before I let myself get excited.