Enabling SmallSat Propulsion for Orbital Maneuverability

The Enabling SmallSat Propulsion (ESP) system can provide spacecraft with both axial and divert and attitude control system (DACS) propulsion. Both the axial and DACS subsystems of the ESP use non-toxic, liquid, non-cryogenic, high-performance propellant drawn from a common source. The propellant components are stored as liquids under their saturated vapor pressures. The ESP employs autogenously pressurized nitrous oxide as an oxidizer, and a mixture of ethane and ethylene is used in the same manner as fuel. Ethane-ethylene mixtures of about 50-50 have the same vapor pressure-temperature curve as nitrous oxide, allowing for lightweight common-bulkhead isothermal tanks. By utilizing the autogenous pressurization capabilities of these propellants instead of an additional pressurization system, greater system simplicity and reliability can be attained. The ESP’s nitrous-ethane-ethylene (NEE) engines can obtain a specific impulse (Isp) of 300 sec, nearly as high as that obtainable using toxic hypergols, but the ESP’s overall system performance is better because of the mass saved by its employment of self-pressurizing common bulkhead tanks. The ESP NEE propellants are cheap, non-corrosive, indefinitely storable on Earth or in space, and compatible with military air transportation requirements, making them a high-performance, green propellant solution for spacecraft engines. The extensive experience and background of the proposed Pioneer Astronautics, Colorado State University, and Moog SBIR team in the areas of propellant formulation, propulsion system and engine design and integration, engine testing, and scale up will lead to rapid development, testing, and implementation of the proposed ESP. In the proposed program, the Pioneer Astronautics/CSU/Moog team will demonstrate an ESP system combining a 250 N NEE liquid propellant thruster for highly responsive orbit change maneuvers with 10 N NEE gas thrusters for DACS. This is an excellent design for an integrated propulsion system for a spacecraft in the 100 kg class. Conceptual designs of ESP systems to meet the needs of 10 kg CubeSats and 1000 kg spacecraft will also be developed, thereby demonstrating concept scalability. With the demonstration of a working prototype ESP system able to meet the needs of an important spacecraft class, and its scalability shown for a wide range of others, the stage will be set for maturation and eventual commercialization of ESP technology. Approved for Public Release | 23-MDA-11401 (14 Mar 23)