Description: Hybird Space Systems (Hybird) is developing a retrobraking propulsion system, named RT-5X, whose initial application is focused on deorbit of spacecraft in LEO. RT-5X combines the “smart” advantages of liquid propulsion (throttleability, restartablility, low impulse bit) with the operational simplicity of solid propulsion (high reliability, low-cost design, storability) in an entirely “green” propellant package. RT-5X offers advantages over the current active and passive deorbit systems, addresses the key pain points of satellite deorbit customers, and incorporates: Ultra-low costs to minimize the financial impact to mission developers Reliable, safe de-orbit transfer through controlled thrust Flexibility across constellation and spacecraft bus sizes Highest in-class propulsive performance Hazard avoidance maneuvering in addition to end-of-life servicing RT-5X is a green, non-toxic, high-performance, deorbit propulsion system consisting of a 5-lbf hybrid rocket engine (including valves and plumbing), a propellant tank, and flying leads for system control. RT-5X integrates with smallsats prior to launch and then performs a controlled, deorbit burn at mission termination. The system includes ΔV margin for additional on-orbit hazard avoidance maneuvers. At the core of RT-5X technical and cost innovation is a 5-lbf hybrid rocket engine. The proposed RT-5X system incorporates a self-pressurizing propellant tank by using Nytrox as an oxidizer. Nytrox is created by bubbling GOX under pressure into N2O until the solution reaches saturation. Oxygen in the ullage dilutes N2O vapor and increases the required decomposition energy barrier by several orders of magnitude. Thus, risks associated with inadvertent thermal or catalytic N2O decomposition are virtually eliminated. Because Nytrox is self-pressurizing, the need for an additional volumetrically inefficient oxidizer pressurization system is eliminated.

Benefits: RT-5X offers a low-cost preventative debris solution that also provides controlled reentry, all characteristics that are well aligned with NASA’s priorities for Debris Remediation. Long term, there is an opportunity to recycle satellite components to use as propellant on RT-5X by using spacecraft structural mass as solid rocket fuel feed stock.

RT-5X offers controlled, deorbit capabilities for small satellite developers and users while minimizing integration, financial, and operational complexities to their missions.