Eco-friendly alternatives to fossil fuels are venturing beyond Earth—and into space.

Water rockets are plenty of fun, but they can be even more fun if you go wild with the engineering. [The Q] is one such experimenter, who built a dual-thrust water rocket that even has a parachute ...

Can water really power a rocket? Scientists are exploring ways to use water as fuel, from splitting it into hydrogen and oxygen to steam propulsion. It might just be the key to the future of space ...