Solid-Fuel Pellet Thrust Actuation for Flight Vehicle Maneuvering
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Solution Overview
Problem
Current flight vehicle control actuation systems face limitations in maneuverability across subsonic and supersonic speeds, both within and outside the atmosphere, due to inefficiencies in drag production and reliability issues with existing fin control surfaces and liquid-fuel divert thrusters.
Innovation Solution
A solid-fuel pellet thrust and control actuation system that employs pivotable aerodynamic control surfaces and solid-fuel pellets to generate gas flow, using a virtual converging/diverging nozzle for additional thrust at subsonic speeds and shock-induced gas diversion at supersonic speeds, allowing for efficient maneuvering across various flight regimes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If fin control surfaces are used for vehicle maneuvering, then control authority is achieved at supersonic speeds, but maneuverability is limited at subsonic speeds and ineffective in exo-atmosphere
Solution Approach 1:
The control system is designed to perform multiple functions: fin control surfaces provide aerodynamic control when atmosphere is present, while divert thrusters provide propulsion-based control in exo-atmosphere or when aerodynamic control is insufficient. This multi-functional approach ensures effectiveness across all flight regimes including subsonic, supersonic, atmospheric, and exo-atmospheric conditions
2Ease of operation
If servo motors are used to actuate control surfaces, then precise control is achieved, but system cost increases significantly and reliability decreases due to moving parts exposure to high g loads
Solution Approach 1:
The system replaces expensive, complex servo motors with simpler, more reliable actuators. The divert thrusters use solid-fuel pellets that are consumed in a single use, eliminating the need for complex mechanical actuators with moving parts that would be exposed to high g loads during launch. This approach trades the longevity of expensive motors for the simplicity and reliability of disposable solid-fuel actuators
3Device complexity
If liquid-fuel divert thrusters are used for vehicle maneuvering, then thrust can be continuously varied and system cost is reduced, but system weight and volume increase significantly
Solution Approach 1:
The system uses solid-fuel pellets instead of liquid-fuel storage tanks and complex delivery systems. The solid-fuel pellets are simple, lightweight, and require no regulators, valves, or complex mixing systems. Each pellet is a self-contained, disposable unit that burns to provide the necessary thrust impulse, eliminating the heavy infrastructure required for liquid-fuel systems
4Adaptability or versatility
If divert thrusters are used for vehicle maneuvering, then effectiveness in exo-atmosphere is achieved, but maneuverability at supersonic speeds is reduced due to high free stream momentum
Solution Approach 1:
The control system combines two complementary mechanisms: divert thrusters that provide force through momentum exchange (effective in exo-atmosphere and at all speeds), and fin control surfaces that provide aerodynamic leverage (effective when atmosphere is present). The system uses both mechanisms together or separately depending on the flight regime, ensuring effective control whether the vehicle is flying through dense atmosphere at supersonic speeds or in the vacuum of space
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides efficient and reliable command authority for flight vehicles across subsonic and supersonic speeds, both within and outside the atmosphere, with reduced weight, cost, and complexity, enhancing maneuverability and reducing packaging issues.
Implementation Method 1
One or more solid-fuel pellets are ignited to expel gas that flows into the cavity creating a cavity pressure
Implementation Method 2
using a virtual converging/diverging nozzle for additional thrust at subsonic speeds
Implementation Method 3
shock-induced gas diversion at supersonic speeds
Data Source
AI summary
A solid-fuel pellet thrust and control actuation system (PT-CAS) provides command authority for maneuvering flight vehicles over subsonic and supersonic speeds and within the atmosphere and exo-atmosphere. The PT-CAS includes a chamber or solid-fuel pellets that are ignited to expel gas through a throat. The expelled gas is directed at supersonic vehicle speeds in atmosphere to a cavity between an aero control surface and the airframe to pressurize the cavity and deploy the surface or at subsonic speeds in atmosphere or any speed in exo-atmosphere allowed to flow out a through-hole in the surface where the throat and through-hole provide a virtual converging/diverging nozzle to produce a supersonic divert thrust. A pellet and control actuation system (P-CAS) without the through-hole provides command authority at supersonic speeds in atmosphere. A restrictor mechanism controls the bleed of pressurized gas from the cavity to the external environment to achieve a deployment time objective for either the PT-CAS or P-CAS.