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

"It has a huge amount of energy potential," says John Rusek ... Hydrogen peroxide, or H2O2, also offers promise in developing low-cost, nontoxic rocket fuels. The chemical differs from water only in ...

Space is the only place where rocket fuel could be more precious than water ... which is used to turn solar energy into a supply of breathable air. Experts have generally found that electrolysis ...