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

solid rocket motors are far too common to be interesting, and even hybrid rocket engines are becoming passé. We’ve never seen a liquid-fuel rocket build before, so that’s what this roundup ...

First conceived of in 1945, this is a rocket that replaces burning chemical fuel with a nuclear reactor that is used to heat up a propellant. This propellant is most likely hydrogen, though ...

He had an a great idea – is it possible to 3D print a solid fuelled rocket, (video ... tried a few experiments to determine the most appropriate fuel/binder/oxidiser ratio, then 3D printed ...