Milestone progress is being made in readying NASA’s Green Propellant Infusion Mission (GPIM) for launch in 2016, a smallsat designed to test the unique attributes of a high-performance, non-toxic, “green” fuel on orbit.
The GPIM marks the first time the United States will use a spacecraft to test green propellant technology, thereby showcasing the innovation needed to develop a fully domestic, green propellant solution for the next generation of space flight.
GPIM is a Technology Demonstration Mission made possible by NASA’s Space Technology Mission Directorate (STMD) and draws upon a government-industry team of specialists. The propellant and new propulsion technology offer several advantages for future commercial, university, and government satellites, such as longer mission durations, additional maneuverability, increased payload space, and simplified launch processing.
The propellant, a Hydroxyl Ammonium Nitrate fuel/oxidizer mix, also is known as AF-M315E. This fuel may replace the highly toxic hydrazine and complex bi-propellant systems in-use today. Ball Aerospace & Technologies Corp. of Boulder, Colorado is the prime contractor for GPIM and is leading the demonstration of the alternative fuel for future space vehicles.
“Green fuel is not only great in terms of handling and safety, it is also a very high-performance rocket fuel,” said Chris McLean, principal investigator for GPIM at Ball Aerospace. “It opens the mission trade space for expanded science operations and/or increased durations.”
The green propulsion system will fly aboard the tried-and-true Ball Configurable Platform 100 spacecraft bus – a cost-saving approach, McLean added, since this is the third build of this bus. The AF-M315E fuel for GPIM was developed by the Air Force Research Laboratory at Edwards Air Force Base in California. The propellant offers nearly 50 percent higher performance for a given propellant tank volume compared to a conventional hydrazine system.
McLean noted that GPIM will use a catalyst technology, pioneered by Aerojet Rocketdyne of Redmond, Washington, also a key partner in the spacecraft mission. “Once the green fuel gets into that catalyst it decomposes exothermically and evolves into gaseous products that come out the engine nozzle…and that’s how we get thrust,” he explained.
GPIM’s on-orbit test of the green fuel will make use of a set of 22 newton and 1 newton-class thrusters. A newton is a unit of force.
“That breakthrough in catalyst technology enabled these thrusters to be developed,” McLean pointed out.
The fabrication and testing of GPIM thrusters is progressing within a specially built test lab at Aerojet Rocketedyne’s Redmond site. Making use of a new vacuum chamber and instrumentation system, work is underway there to ready the 22-newton and 1-newton thrusters.
The 22-newton thruster will fire simultaneously along with four smaller 1 newton thrusters aboard the GPIM satellite to make orbit changes, as well as perform pointing and hold tests during the early months of an expected year-long flight. Long-life catalyst
“For the last several years our research and development group that’s dedicated to this technology has made several, quite astounding leaps forward,” said Jonathan Overly, senior project engineer on the GPIM program at Aerojet Rocketdyne.
Overly said the company’s work has helped to make the GPIM mission possible in many ways, particularly in increasing the life and the performance capability of the thrusters.
Source: NASA
