water ice

Spacecraft might one day refuel on the moon or Mars using plain old ice. A small rocket flew earlier this month on an environmentally-friendly propellant consisting of aluminum powder and water ice.

The "ALICE" fuel mixture being developed by Purdue University and Pennsylvania State University could someday replace liquid or solid rocket propellants, and possibly enable higher performance as well. The implications for space exploration could also mean accessible fuel reserves at future lunar or Martian outposts, which naturally attract the interest of NASA and the Air Force Office of Scientific Research.