SAN FRANCISCO – Rubicon Space Systems has delivered the propulsion system for a NASA technology demonstration mission scheduled to launch in October.
The mission, Green Propulsion Dual Mode (GPDM), will showcase both multimode propulsion, integrated chemical and electric thrusters, and ASCENT, the green propellant developed by the U.S. Air Force Research Laboratory.
It will be the first combined chemical and electric propulsion system in space and a key test of ASCENT, Daniel Cavender, director of Rubicon, a division of Plasma Processes, told SpaceNews.
NASA is testing ASCENT (short for Advanced Spacecraft Energetic Non-Toxic) because it promises a 50 percent increase in specific impulse density compared with hydrazine, plus easier ground handling, according to a NASA Marshall Space Flight Center briefing on GPDM.
Rubicon’s ASCENT chemical propulsion module, called Sprite, is being paired with Massachusetts Institute of Technology electrospray thrusters. The four electrospray thrusters delivered to NASA in September share Sprite’s propellant tank, control valves and a feed system.
Engineers building the six-unit cubesat, roughly the size of a large shoebox, have carefully considered the lessons of Lunar Flashlight, a NASA cubesat that failed to reach lunar orbit in 2023. Because debris clogged propellant lines for Lunar Flashlight, Rubicon used CT scanning to ensure Sprite’s propellant lines were free of debris or particulates, and conducted a hot-fire test of the system.
“We have certainly done our due diligence in addressing the FOD [foreign object debris] concern of Lunar Flashlight,” Cavender said.
Component to Product Supplier
Delivering the propulsion module to NASA was an important milestone for Huntsville, Alabama-based Rubicon, as well.
“This is the first time that we’ve produced an integrated propulsion system,” Cavender said. “We’ve gone from being a component manufacturer to an integrated, functional product manufacturer.”
Cavender began working with ASCENT while working in the NASA Technology Demonstration Mission during NASA’s Green Propellant Infusion Mission, launched in 2019. He was also NASA Marshall’s Lunar Flashlight project manager.
ASCENT’s “big draw” is its specific impulse density, Cavender said. “For a small spacecraft that’s constrained on volume, you need higher efficiency to gain capability.”
What’s more, the safety considerations that surround ASCENT are greatly reduced from hydrazine fueling operations, Cavender said, meaning “you can fuel at your factory, you can fuel en route, you can fuel on the launch vehicle.”
Electrospray
Like NASA, the Defense Department is interested in electrospray thrusters. The Defense Innovation Unit solicited proposals in October to spur development of the technology, which generates thrust by accelerating charged particles.
