Flight Works is proposing to leverage its ongoing development of a high delta-V (> 3 km/s) pump-fed “green” monopropellant transfer stage to obtain an even higher performance, high thrust, pump-fed hypergolic bipropellant stage designed specifically for small spacecraft deep space missions. The costs targeted for such stage would enable dedicated interplanetary missions with CubeSats and Nanosats at a price measured in millions as opposed to high tens of millions.
The proposed concept benefits from the extensive micro-pump technology developed at Flight Works for hypergolic, storable bipropellant propulsion systems, combined with space system-level know-how of its principals. With the technology, a pump-fed monopropellant system outperforms a high-performance pressure-fed biprop system; this performance is further enhanced here with a pump-fed biprop system. The result is a growth in payload capability of over 40%. The other benefit is a low-pressure set of tanks, reducing efforts associated with range safety compliance.
The biprop stage also leverages the commonality with the avionics suite of the monopropellant stage. This approach allows reducing the development scope, costs and risks while providing a high-performance, high-thrust transfer stage optimized for deep space missions.
The high thrust allows for rapid, efficient transfers, compared with electric propulsion systems which require many months to reach the targeted orbit. Also, the system can either stay attached to the small primary payload for long term mission operations or deploy it onto its destined trajectory, thus enhancing mission flexibility.
With a stage designed to provide over 3 km/s delta-V to a nanosat payload for deep space missions, it can be used for NASA lunar and interplanetary applications. 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. 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 missions on small dedicated launch vehicles where additional delta-V is required, as well as space-tug applications on Falcon-9 rideshare launches. The stage can also be used for other applications such as orbital inspectors.