NASA Spacecraft to Test ‘Green’ Propellant Passes Major Pre-flight Milestone

A Ball Aerospace engineer adjusts the thermal insulation on NASA’s Green Propellant Infusion Mission spacecraft bus following integration of the propulsion system. (Credit: Ball Aerospace)
A Ball Aerospace engineer adjusts the thermal insulation on NASA’s Green Propellant Infusion Mission spacecraft bus following integration of the propulsion system. (Credit: Ball Aerospace)

HUNTSVILLE, Ala. (NASA PR) — Like all rocket engines, the small thrusters that a spacecraft or satellite fires to maintain or change positions need fuel. Currently, many use hydrazine — a toxic and corrosive fuel that requires special handling and equipment.

NASA’s Green Propulsion Infusion Mission (GPIM) recently took another major step toward demonstrating the capabilities of a new propellant that is safer to handle on the ground and more efficient for thrusters in space. The GPIM spacecraft has passed a major flight readiness milestone marking the successful completion of functional and environmental testing of its systems and software, and is on track for launch in early 2017.

“We are increasingly reliant on satellites for communications, for monitoring weather and conditions on Earth and for exploration of the universe,” said Steve Jurczyk, associate administrator of NASA’s Space Technology Mission Directorate. “It’s important that we develop technology that increases protections for launch personnel and the environment, and that has the potential to reduce costs.”

GPIM will demonstrate the practical capabilities of a hydroxyl ammonium nitrate based fuel/oxidizer propellant blend, known as AF-M315E, developed by the U.S. Air Force Research Laboratory at Edwards Air Force Base in California. The new propellant is 45-percent denser than hydrazine, meaning more of it can be stored in containers of the same volume. Coupled with a greater Isp than hydrazine, this means there is approximately a 50-percent increase in spacecraft maneuvering capability for a given volume. AFM-315E also has a lower freezing point than hydrazine, requiring less spacecraft power to maintain its temperature.

AF-M315E, less toxic than traditional chemical fuels like hydrazine, requires fewer handling restrictions and less special equipment. That could shorten launch processing times, resulting in lowered costs.

“There are always going to be situations in which it makes sense to use hydrazine fuel,” said Chris McLean, principal investigator for GPIM and staff consultant at Ball Aerospace and Technologies Corp. in Boulder, Colorado, prime contractor for the mission. “But after GPIM, when we’re planning missions where this new green propellant has the potential for significant benefits, we’ll be able to say, ‘This has been demonstrated on orbit. Let’s take advantage of these improvements for our mission.'”