CU Aerospace (CUA) proposes the scaling of an alternative very low-toxicity monopropellant thruster to a 0.5 N class engine. CMP-8 (CUA Mono-Propellant 8) is a non-detonable yet energetic COTS formulation that possesses many system-level advantages including lower cost (COTS propellant and non-refractory thruster construction), lower thermal load (<1000°C flame temp), low viscosity (comparable to water), and common materials compatibility (aluminum, stainless steels, and most elastomers). The existing technology has achieved 187 s specific impulse at 160 mN thrust during demonstrated continuous firing times exceeding 10 minutes. CMP-8 has demonstrated a shelf life exceeding 1200 days (a storage test ongoing since 2015). Phase I studies include preliminary hazard classification of CMP-X (a less energetic formulation allowed on air transport) to establish Insensitive Munitions (IM) characteristics and provide guidance for large scale storage and feed (i.e. critical diameters) as well as catalyst risk reduction studies and characterizations. CMP-X is designed not for highest performance Isp, but as a monopropellant option for customers who can accept a modest 20% performance penalty (relative to AF-315E and LMP-103S) for the advantages of air transportability, considerably fewer range safety concerns, lower flame temperature resulting in considerably less thermal soakback into the spacecraft, and longer continuous thrust burns. CMP-X retains the ability to scale in thrust magnitude and requires minimal catalyst bed warmup time.The primary Phase I technical objective is to produce a flight-like TRL 5 thruster head and improve the integrated system design in order to deliver an integrated TRL 6 CubeSat propulsion system with ACS by the end of Phase II. The estimated Phase II volumetric impulse of a 2U-sized MPUC deliverable is >1200 N-sec with a peak power draw of <5 W and 185 s specific impulse.
MPUC responds to goals in NASA’s Roadmap for In-Space Propulsion with a focus on long life and cost reduction both with common COTS construction materials. MPUC has demonstrated performance that will yield volumetric impulse levels above those of legacy hydrazine systems. Its lack of detonation and demonstrated storability makes it a prime candidate for missions where costs and logistics are dominated by system transportation and range safety concerns. Potential missions include orbit change, drag makeup, and deorbiting.
Potential MPUC system applications include drag makeup allowing extended-duration low altitude orbits, low Earth orbit raising, and/or deorbiting for micro/nanosatellites. The MPUC green monopropellant system offers affordable access to Cubesat propulsion and is easily scalable to larger sizes depending on mission requirements to meet the differing needs of users in DOD, industry, and academia.