Satellite Deorbiting via Coplanar Masts and Gravity Gradient

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Solution Overview

Problem

Satellites in low Earth orbit face challenges in deorbiting without dedicated high-mass systems or significant hydrazine use, and existing aerobraking solutions struggle to maintain stable attitude at high altitudes, leading to reduced aerodynamic braking effectiveness.

Innovation Solution

Combining gravity gradient stabilization at high altitudes with aerodynamic stabilization at lower altitudes using coplanar masts with adjustable masses and angles to maintain a consistent aerodynamic attitude, optimizing the aerodynamic braking area without energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aerobraking sails are deployed for satellite deorbiting, then the deorbiting capability is improved, but the satellite attitude stability deteriorates at high altitudes

Engineering Contradiction:

Improvedeorbiting capabilityVSAvoidsatellite attitude stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The deorbiting system is segmented into two distinct functional components: aerobraking sails for deorbiting capability and gravity gradient stabilization masses for attitude stability. This segmentation allows each component to independently fulfill its specific function without interfering with the other, resolving the contradiction between deorbiting effectiveness and attitude stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Gravity gradient stabilization masses are positioned on extended booms to create a counterbalancing effect that stabilizes satellite attitude. These masses act as artificial weights that generate restoring torques to counteract attitude disturbances, maintaining stable orientation even when aerobraking sails are deployed at high altitudes where atmospheric stabilization is insufficient.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

2Reliability

If dedicated deorbiting systems of high mass are carried on board, then the deorbiting reliability is improved, but the satellite total mass increases

Engineering Contradiction:

Improvedeorbiting reliabilityVSAvoidsatellite total mass

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The satellite utilizes the Earth's gravity field and residual atmosphere as free resources for deorbiting. The gravity gradient stabilization system leverages the Earth's gravitational field, while the aerobraking sails exploit atmospheric drag, eliminating the need for dedicated high-mass propulsion systems or consumable propellants.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention replaces traditional mechanical propulsion-based deorbiting systems with a passive aerobraking system. Instead of using engine thrust to lower orbit, the satellite uses atmospheric drag force generated by the sails, significantly reducing the mass of active deorbiting equipment required.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If aerodynamic braking area is maximized, then the deorbiting efficiency is improved, but the satellite attitude control becomes more difficult

Engineering Contradiction:

Improvedeorbiting efficiencyVSAvoidattitude control

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The gravity gradient stabilization system acts as an intermediary mechanism that mediates between the aerodynamic forces from the sails and the satellite's attitude control requirements. By providing passive stabilization through gravitational torques, it allows the sails to maintain large aerodynamic area for efficient deorbiting while automatically maintaining appropriate attitude without active control intervention.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach enables efficient deorbiting by maximizing the aerodynamic braking area and maintaining satellite stability across altitudes, reducing the mass of the deorbiting system while adhering to regulatory timelines.

Implementation Method 1

combining gravity gradient stabilization at high altitudes with aerodynamic stabilization at lower altitudes

Methodology Applied

Scientific EffectGravity gradient: Gravitation

Implementation Method 2

aerobraking sails, i.e. surfaces that use the residual atmosphere present in low Earth orbit as an aerodynamic brake to brake and to slow an object, and thus in the end to reduce the altitude of its orbit

Methodology Applied

Scientific EffectAerodynamic braking: Drag

Data Source

PatentUS10723490B2Satellite deorbiting system

Publication Date: 2020.07.28 ARIANEGRP SAS

AI summary

A device to stabilize and deorbit a satellite includes a pair of coplanar masts, each one carrying at least one membrane forming an aerobraking web. The masts are fixed to the satellite along non-parallel axes. Each mast is provided on the opposite end of the satellite with a mass to generate a gravity gradient. The end of each mast is fixed to the satellite. The masts form, with the bisectrix between the masts, a fixed angle to align the bisectrix with the satellite speed vector at any altitude.