Low-Cost, Safe, Bi-Propellant Propulsion for Smallsats

Summary  Parabilis Space Technologies, a HUBZone-certified small business, is proposing a novel low-cost, high-performance, modular, propulsion engine utilizing nitrous oxide (N2O) and alkane (either  propane or ethane) as green propellants in response to solicitation AF211-CSO1 “Phase I Open Call for Innovative Defense-Related Dual-Purpose Technologies/Solutions with a Clear AF Stakeholder Need”.  This proposal addresses AF Science and Technology (S&T) Strategic capability "Speed and Reach of Disruption?and Lethality".  While nitrous oxide/alkane propulsion systems have existed for decades, such systems have not been developed into usable satellite propulsion systems. Parabilis Space Technologies, with extensive experience using nitrous oxide for low-cost propulsion systems and substantial experience developing liquid bi-propellant thrusters, is uniquely qualified to adapt an existing system to use alkane propellants, and demonstrate the technology on-orbit, resulting in meeting a wide range of DOD propulsive needs at a very low cost.  Problem  On-orbit maneuverability is becoming a necessity to avoid threats and accidental collisions.  Regulatory agencies are proposing mandatory propulsion for satellites above a certain altitude in order to manage orbital debris as space becomes more crowded. However, low-cost, high-impulse propulsion for satellite maneuvering that is also safe for ridesharing does not exist. Available smallsat propulsion systems cost between $1M-$2M (for ESPA class) and/or have significant other drawbacks such as low performance, high power requirements, or high toxicity that requires expensive SCAPE suit operations.  Nitrous oxide and ethane can meet Air Force/ Space Force and commercial needs at approximately half the cost.  Innovation  Parabilis proposes to adapt an existing self-pressurizing hybrid propulsion system for a novel, non-toxic propellant combination: nitrous oxide and ethane. Ethane is an alkane with vapor pressure curves that are very amenable to the creation of in-space propulsion systems. Ethane has higher specific impulse and vapor pressure, which will trade better (compared to other alkanes like propane) for applications requiring rapid maneuvering for threat/collision avoidance. The proposed solution adds a more scalable, higher performance option to Parabilis’ product line of in-space self-pressurizing propulsion systems, albeit at slightly higher cost and complexity than Parabilis’ hybrid-rocket-motor based systems.? In this Phase I, Parabilis will identify specific Air Force/Space Force requirements, then design a radiative, fuel-cooled, or porous wall propulsion solution.