Description: Parabilis Space Technologies is proposing Phase II development of a high-performance hybrid rocket stage suitable for both small spacecraft maneuvering and for trans-lunar orbit injection in response to solicitation Z8.09, Small Spacecraft Transfer Stage Development. This effort will leverage both the successful Phase I and a previous successful NASA-funded R&D at Parabilis for a “NanoLaunch” hybrid upper stage and the design of an appropriately scaled-up hybrid motor. The proposed stage is economical, non-toxic, non-cryogenic, restartable, and compatible with multiple “venture-class” launch vehicles. The stage will be offered in two sizes, one of which will be capable of delivering 25 kg payloads into translunar trajectories when launched abord a Rocket Lab Electron vehicle. A larger “Grande” stage will be capable of injecting 60 kg payloads into translunar trajectories. During Phase I, Parabilis designed, manufactured, and hot fire tested a near full-flow rate prototype motor at sub-duration and sub-motor external dimensions. This significantly reduced both technical risk and the effort required for flight-like prototypes which will be tested in the proposed Phase II effort. The Phase I motor test showed smooth catalytic ignition, stable combustion, and good combustion efficiency. During Phase II, the flight vehicle systems engineering will be updated, and an updated full-scale motor prototype will be manufactured and then hot fire tested at Parabilis’ rocket test facility. Multiple test/design cycles will be performed with the goal of maximizing performance and characterizing the motor over the equivalent of the full duration operating range and obtaining regression characteristics such that fuel residuals can be minimized in future designs. In parallel, a flight weight pump and feed system will be designed that meets the requirements of the stage architecture. This development path addresses the most critical items for implementing the innovation.

Benefits: The proposed innovation is ideal for low-cost delivery of a 25-35kg payload, similar to the CAPSTONE/NRHO Pathfinder, into a translunar trajectory. A lower-than-maximum payload, or an elliptical parking orbit will provide sufficient delta-V for delivery into lunar orbit. The proposed hybrid propulsion solution can address other NASA needs including an upper stage for small LVs capable of taking payloads to LEO, a low-cost transfer vehicle for interplanetary missions, or an ascent vehicle for sample return missions.

Hybrid propulsion is of direct interest to the USSF. Hybrid propulsion provides a storable, safe “standby” solution for 24-hour callup missions, protect space assets from threats at lower cost than existing systems, and provide lower-cost hypersonic flight testing or target drones. The civil and commercial market includes remote sensing, commercial comm, and interplanetary scientific customers.