Description: Flight Works is proposing to continue the development and demonstration of a low cost, compact, high performance transfer stage which enables dedicated missions to cislunar and deep space (such as Mars rendezvous) with small launchers like Virgin Orbit’s LauncherOne and ABL’s RS-1. More than a stage, the system features a full set of avionics creating a bus with extensive propulsion capabilities. The avionics is based on flight-proven large CubeSat avionics from partner Astro Digital. The high performance is enabled by Flight Works’ micropump-fed propulsion technology matured over the last few years for small spacecraft combined with the high density-specific impulse (Isp) provided by the green monopropellant ASCENT. The green propellant can be stored cold to minimize heating power and a low-power pumped loop can be used to slightly warm the propellant prior to use. The result is a simple, versatile, cost-effective stage with full bus functionality and with performance capabilities similar to that of a traditional bipropellant pressure-fed stage and which can be configured for cislunar and even Mars missions. Other benefits include scalability; use of green propellants and low-pressure tanks minimizing range safety operations and costs; high thrust for rapid, efficient transfer (compared with electric propulsion systems which have to be launched at higher orbits to avoid low altitude drag and which can require months to reach the targeted orbit while exposing the system to the damaging radiation of the Van Allen belts); minimized size provided by a high performance propulsion system; and attitude control system for long term operations.

Benefits: A stage providing over 4.3 km/s delta-V to a nanosat payload can be an enabler for many NASA lunar and interplanetary missions. These include missions similar to the NASA Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE), or follow-ons to NASA’s Mars CubeSat missions MarCO-A and -B, and unlike MarCO, could enable Mars Orbit Insertion. It can also be used for NASA LEO and GEO nanosat missions, whether launched as dedicated or as secondary payloads.

Non-NASA applications include commercial and DoD missions requiring high orbital maneuver capabilities. These include dedicated missions on small launch vehicles where additional delta-V is required, as well as commercial space-tug applications, e.g. on Falcon-9 rideshare launches. The stage can also be modified for other applications such as orbital inspectors from LEO to cislunar operations.