Low Cost Hybrid Rocket Orbital Transfer Stage

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 RD 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. Parabilis is proposing Phase II development of a high-performance hybrid rocket stage for trans-lunar orbit injection and maneuvering. NASA has publicly stated its interest in exploring the lunar environment using small spacecraft and purchasing lunar transfer services from a commercial space provider to supply its planned Gateway and any future lunar base and/or operations. In order to perform these missions, a new class of launch vehicle stage must be developed that is adaptable to existing economical small launch vehicles, and offer mid to long-term storage, non-hazardous operation and ability to fit within limited science budgets. The proposed stage is economical, non-toxic, non-cryogenic, catalytically ignited, restartable and will deliver 25 kg (or larger) payloads into translunar trajectories. This stage has heritage in Parabilis’ “NanoLaunch” upper stage. The proposed stage will be scaled up from Nano Launch and will use a pump-powered combustion cycle. The stage is designed to be compatible with small LVs, specifically Rocket Lab’s Electron. During Phase I, a Hydrogen Peroxide-based hybrid motor of relevant scale to that needed for the low-cost lunar stage was designed, built and successfully hotfire tested. The motor ignition was achieved using a catalyst bed without any need for preheat or secondary fluid injection. Full chamber pressure occurred in 1.5 sec. Combustion was smooth for a first motor iteration with chamber pressures oscillations of 8% (vs JHU CPIA default criteria of 5%) and 94% combustion efficiency. Oxidizer-to-fuel ratio and regression rate was within expectations. Motor case temperature rise and nozzle erosion were both negligible. Following the Phase I, the Objectives for Phase II will substantially reduce the technical risk for the motor and feed system, positioning Parabilis to build and qualify a full stage during a subsequent effort. The objectives for the Phase II effort include: • Maturation of the Lunar Stage Vehicle • Design of a flight-weight pump and feed system • Hot fire testing of a flight-size prototype motor Phase II testing will effectively consist of a series which will address any immediate issues encountered during a set of short duration firings and refined series to collect full duration data. Completion of these objectives will provide data and reduce technical risk such that a flight-like motor and full propulsion system may be completed following the Phase II effort.
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.