The propulsion subsystem for NASA's Green Propellant Infusion Mission (GPIM) has been integrated onto the spacecraft, moving the mission another major step toward scheduled launch in 2016. The propulsion subsystem will be the primary payload on the mission’s spacecraft. The mission will demonstrate the practical capabilities of a hydroxyl ammonium nitrate-based fuel/oxidizer propellant blend developed by the Air Force.

A Ball Aerospace engineer adjusts the thermal insulation on NASA’s GPIM spacecraft bus following integration of the propulsion system. (Ball Aerospace)

The fuel requires fewer handling restrictions, and has potentially shorter launch processing times, resulting in lowered costs. More of the propellant can be stored in tanks of the same volume, resulting in a 50-percent increase in spacecraft maneuvering capability for a given volume. It also has a lower freezing point than hydrazine, requiring less spacecraft power to maintain the propellant temperature.