Launch Vehicle Final Stage Nosecone Re-entry Stability

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Solution Overview

Problem

The recovery of the final stage of a launch vehicle is challenging due to its high re-entry velocity and the need for additional fuel to decelerate, which affects payload capacity and component reuse, and existing methods face stability issues during re-entry and landing.

Innovation Solution

A multi-purpose nosecone is positioned at the engine-end of the final stage, providing stability during re-entry by placing the center of gravity ahead of the center of pressure, and includes features for controlled soft landing, such as parachutes and deployable panels, eliminating the need for continuous fuel control during re-entry and facilitating a stable descent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional fuel is carried in the final stage for deceleration and recovery operations, then the recovery capability is improved, but the maximum payload mass that the final stage can carry is reduced

Engineering Contradiction:

Improverecovery capabilityVSAvoidmaximum payload mass

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The final stage is divided into separate functional modules: a reusable engine section and a disposable upper stage. The engine section contains the fuel tanks and propulsion system, while the upper stage carries the payload. This segmentation allows the engine section to be recovered and reused without requiring the entire final stage to be recovered, thereby reducing the fuel required for recovery operations and increasing payload capacity.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a powered control landing is used for final stage recovery, then the component reuse is improved, but the additional fuel requirement increases

Engineering Contradiction:

Improvecomponent reuseVSAvoidadditional fuel

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The final stage is segmented into a reusable engine section and a disposable upper stage. The engine section is equipped with propulsion systems for controlled landing and recovery, while the upper stage is discarded after payload deployment. This allows the expensive engine components to be recovered and reused with minimal fuel consumption, as only the engine section requires powered landing capability.

Inventive Principle:

Principle #1Segmentation

3Stability of the object's composition

If the center of pressure is placed ahead of the center of gravity during re-entry, then the aerodynamic stability is improved, but the control complexity increases due to continuous engine maneuvering requirements

Engineering Contradiction:

Improveaerodynamic stabilityVSAvoidcontrol complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Instead of placing the center of pressure ahead of the center of gravity as in conventional designs, the final stage is configured with the center of gravity ahead of the center of pressure during re-entry. This inverted configuration provides inherent aerodynamic stability, eliminating the need for continuous active control and simplifying the guidance and control systems.

Inventive Principle:

Principle #13The other way round (Inversion)

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

This configuration enhances the stability and control of the final stage during re-entry and landing, reduces fuel requirements, and protects the engine and components, enabling successful recovery and reuse with minimal additional fuel.

Implementation Method 1

providing stability during re-entry by placing the center of gravity ahead of the center of pressure

Methodology Applied

Scientific EffectAerodynamic stability: Aerofoil

Implementation Method 2

includes features for controlled soft landing, such as parachutes and deployable panels

Methodology Applied

Scientific EffectParachute drag: Parachute

Data Source

PatentUS11565833B2Recovery of a final stage of a spacecraft launch vehicle

Publication Date: 2023.01.31 PLANETARY SYSTEMS CORP

AI summary

After deploying its payload, the final stage of a launch vehicle is maneuvered to couple the nosecone of the launch vehicle to the ‘rear’, or ‘engine-end’ of the final stage. The nosecone covers the engine of the final stage, to protect the engine and related components from the heat of re-entry and the impact of landing. Placing the nosecone over the engine and orienting the combination such that the nosecone ‘leads’ the final stage during re-entry, places the center of gravity of the combination ahead of the center of pressure in the direction of travel. Accordingly, the combination is inherently stable as it re-enters the atmosphere and falls to earth. Parachutes and directional devices are used to provide a controlled soft landing.