Adaptable solid-hybrid rocket for crew escape and orbital injection propulsion

#The present invention relates to an adaptable solid hybrid rocket system which combines solid and hybrid propulsion for providing emergency escape propulsion or orbital injection propulsion to a reusable spacecraft such as a manned spacecraft.

#Future generations of space vehicles will have a manned crew transfer vehicle which rides on a reusable launch vehicle. The crew transfer vehicle may be injected into orbit to eventually dock with a space station. The crew transfer vehicle requires a crew escape system to supply propulsion and control for the crew to escape from the reusable launch vehicle, as directed by a health monitoring system, under each and all reusable launch vehicle ascent flight phases.

#The crew escape system must be capable of very rapid crew transport away from impending danger. The time period from health monitor sensing of a problem to the crew escape system fire-signal may be on the order of one second. Consequently, the crew escape system propulsion must provide very high thrust coupled to very high control maneuverability immediately upon command. High thrust is needed for the first few seconds and must be followed by a longer period of sustained propulsion. Previous propulsion applications with a similar set of requirements have always depended on solid rocket propulsion to generate immediate/very high thrust. Alternate propulsion systems, i.e. liquids, hybrids, gels, require significantly longer time duration to achieve steady-state thrust, and do not achieve the high thrust/weight ratios inherent to solid rockets.

#FIG. 1 is a sectional view of a first embodiment of a propulsion system in accordance with the present invention; and

#FIG. 2 is a sectional view of an alternative embodiment of a propulsion system in accordance with the present invention.

#In accordance with the present invention, an adaptable solid-hybrid rocket propulsion system 10 is provided which integrates solid and hybrid propulsion in a multi-mission adaptable configuration capable of providing emergency escape propulsion during an emergency portion of an ascent flight, or orbital injection propulsion during normal ascent flight operation. The propulsion system 10 may be used to launch manned or unmanned space vehicles.

#Referring now to FIG. 1, a propulsion system 10 in accordance with one embodiment of the present invention is illustrated. The propulsion system 10 includes an outer casing 12 and a thrust nozzle 14. The outer casing 12 may be formed from any suitable material known in the art such as a lightweight, high strength composite material. The thrust nozzle 14 is mounted to the casing 12 and provides variable thrust control vector and slew rate, and thus control maneuverability, during operation. Any suitable means known in the art may be used to mount the thrust nozzle 14 to the casing 12. In a preferred embodiment, a fluid bearing 15 is used to make the nozzle movable. A fluid bearing is desirable to minimize the load required for pivoting and maximizing achievable thrust vector control angle and slew rate. The movable nozzle approach contemplated herein results in high crew escape system maneuverability and also allows electromechanical control actuation of the thrust nozzle 14.

#The propulsion system 10 has a solid propellant element 16 within the casing 12. The solid propellant element 16 may be formed from any suitable solid propellant known in the art which may be expended quickly to support escape operations or slowly to support orbital injection operations. In the present invention, the thrust generated by the solid propellant element 16 is advantageously controlled via a nozzle throat area change. The nozzle throat area change may be accomplished using any suitable means known in the art; however, it is preferred to use an ejectable booster nozzle nozzle liner 18 to change the throat area 20. The nozzle liner 18 may be relatively thick and thus reduces the throat area 20 of the nozzle during escape boost thrust, thus generating a desirable high burst acceleration. If escape operations are no longer necessary during the ascent portion of the vehicle's flight, the nozzle liner 18 may be ejected to increase the throat area 20 of the nozzle, thus enabling sustain-thrust during a normal orbital injection phase of the ascent flight. Ejection of the nozzle liner 18 may be accomplished in any suitable manner known in the art.