NASA Image of the Day: 'Green' Alternative Fuel Set for First In-Space Test
'Green' Alternative Fuel Set for First In-Space Test Satellites love hydrazine – a type of space propellant – but it's toxic to people and extremely difficult to handle. A non-toxic alternative will be put to the test with NASA's Green Propellant Infusion Mission (GPIM), set to launch on a SpaceX Falcon Heavy rocket.