Foldable Rocket Stage Propulsion for Controlled Landing
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Solution Overview
Problem
Reusable rocket stages face risks during landing due to limited aerodynamic control, engine response time, proximity to landing surfaces, and the need for remote landing sites, which limits launch frequency and safety.
Innovation Solution
Incorporation of foldable propulsion units and airbrakes with sensors and actuators for precise altitude and flight control, allowing for controlled landing on various surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If liquid propellant is used for landing, then the rocket can achieve controlled descent, but the risk of fatal accidents increases due to engine proximity to landing surface and miscalculation risks
Solution Approach 1:
The rocket is divided into multiple stages with separate propulsion systems. The first stage uses liquid propellant for powered ascent and initial descent, while the second stage uses solid propellant for the final landing phase. This segmentation isolates the high-risk liquid propellant operations from the safer solid propellant landing, reducing overall accident risk while maintaining controlled descent capability.
Solution Approach 2:
A second stage with solid propellant acts as an intermediary between the liquid propellant first stage and the landing surface. This intermediate stage provides a safety buffer, allowing the rocket to transition from liquid to solid propellant propulsion before reaching the critical landing phase, thereby reducing the hazards associated with liquid propellant operations near the landing surface.
2Device complexity
If a single engine is used for both thrust vectoring and slowing down, then device complexity is reduced, but response time for correction maneuvers becomes too slow
Solution Approach 1:
The propulsion system is segmented into multiple independent engines distributed across different stages. The first stage engines handle thrust vectoring and initial deceleration, while the second stage engines provide final landing thrust. This segmentation allows each engine to be optimized for its specific function and enables faster response times through parallel operation of multiple independent propulsion units.
Solution Approach 2:
The rocket employs dynamic switching between different propulsion modes and stages. The control system can dynamically activate different engine combinations based on flight phase requirements, enabling rapid response to correction maneuvers by selecting the most appropriate engines for the current operational state rather than relying on a single fixed configuration.
3Reliability
If remote landing sites are used for liquid propellant rockets, then safety is improved, but launch frequency is limited by availability of remote areas
Solution Approach 1:
The solid propellant second stage provides universal landing capability that can be used at various locations including remote sites, coastal areas, and even urban environments. This multi-functional propulsion system enables the rocket to land safely at diverse locations without being constrained by the need for specialized remote landing zones, thereby increasing launch frequency while maintaining safety.
Solution Approach 2:
The propulsion system transitions from liquid to solid propellant between stages, changing the operational parameters to enable more flexible landing locations. The solid propellant phase allows for adjusted burn characteristics and controlled descent rates that can accommodate various landing site types, expanding the operational envelope beyond remote areas alone.
4Device complexity
If the engine location is limited to the bottom of the rocket, then structural simplicity is maintained, but aerodynamic control is limited to maximum rotational range
Solution Approach 1:
The propulsion system is distributed across multiple stages with engines positioned at different locations. The first stage engines are located at the bottom for launch, while the second stage engines are positioned higher up. This spatial segmentation allows the aerodynamic center of mass to be adjusted during flight by activating different stage engines, thereby expanding the effective aerodynamic control range beyond what is possible with a single bottom-mounted engine.
Solution Approach 2:
The engine arrangement transitions from a single-point (bottom) configuration to a distributed three-dimensional configuration across multiple stages. This dimensional change in engine positioning creates multiple aerodynamic leverage points, enabling greater rotational freedom and enhanced aerodynamic control capability while maintaining relatively simple individual engine designs.
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
Enhances landing safety and flexibility by reducing the risk of accidents and enabling more frequent launches by allowing controlled landings on diverse surfaces.
Implementation Method 1
at least one propeller mounted to the at least one motor, configured to generate a thrust to propel the rocket
Implementation Method 2
a plurality of foldable airbrakes spaced around a circumference of the body, where each airbrake comprises at least one airbrake actuator, configured to actuate the plurality of foldable airbrakes
Data Source
AI summary
A stage of a rocket is disclosed. The rocket stage may include: a body, and a plurality of foldable propulsion units spaced around a circumference of the body, where each propulsion unit comprises: a folding beam; at least one motor mounted to the folding beam, and at least one propeller mounted to the at least one motor, configured to generate a thrust to propel the rocket.