CU Aerospace (CUA), NearSpace Launch and the University of Illinois at Urbana-Champaign will build and flight-test the 6-unit Dual Propulsion Experiment (DUPLEX) CubeSat equipped with two novel micro-propulsion systems. The two systems include a Monofilament Vaporization Propulsion (MVP) system and a Fiber-fed Pulsed Plasma Thruster (FPPT). Both systems use solid polymer propellants that the propulsion systems transform into vapor and plasma, respectively. These systems were developed with NASA Small Business Innovation Research (SBIR) funding and offer high performance, low cost, and safe pre-launch processing.

Common propulsion systems utilize pressurized gases, liquids, or highly chemically-reactive solids, which complicate handling and can lead to safety concerns. The MVP thruster system uses the high-density, nontoxic, solid propellant Delrin. This propellant is stored as fiber on a spool and fed to the thruster with technology proven in 3D printing applications. The propellant feed system uses technology based upon 3D printers to both feed and pre-melt the Delrin filament propellant into the heater tube, where it is de-polymerized, evaporated, and superheated upstream of a supersonic nozzle. This approach enables very long-term storage, a temperature envelope beyond that of a typical satellite’s onboard electronics, and a competitive delta-v (∆V) performance with no significant spacecraft hazards. The FPPT uses Teflon and combines a high accuracy fiber feed mechanism with high-capacity capacitors to produce adjustable thrust. The ability to control both power per pulse and feed rate has enabled CUA to vary both the specific impulse in a range between 2400 – 4000 s and the thrust from 0 – 100% in this innovative FPPT system. The proposed one-unit (1U) FPPT system utilizes the completely non-toxic solid propellant Teflon with a benign exhaust, has no corrosive, leaking, or propellant plugging issues, and has on-demand throttleable thrust with no warmup time requirement. This project will demonstrate both systems in space to further their infusion potential and commercialization.

Conventional propulsion systems require a pressure vessel to store their propellants in addition to requiring heating of the stored propellants. These systems also often use propellants that are toxic or hazardous. This complicates handling and leads to additional costs. Many rideshare opportunities do not allow pressure vessels or require extra testing and funding for such systems. The systems to be demonstrated under this NASA Tipping Point are unique as they use nontoxic solid propellants, do not require pressure vessels, and avoid other common challenges such as leaking tanks, malfunctioning valves or corrosion. It also enables missions where propellant has to be in storage for a long time while the spacecraft is not powered.

Both systems are useable as micro-thrusters, and directly applicable for small satellite missions or maneuver thrusters for larger spacecraft. The FPPT thruster can be scaled up to larger systems.