AEOLDOS – Areodynamic End Of Life DeOrbit SystemMalcolm McRobbClyde Space Ltd.

Do we have a problem?• Access to LEO vital for many services:

• Crop monitoring• Navigation• Observation• Disaster Response• Etc…

• 1978 – Donald J. Kessler proposes a scenario whereby the density of debris in LEO reaches a point such hat collisions between objects cause a cascading effect.

• Approx’ 13,000 objects bigger than a softball; 100,000 pieces bigger than a penny; tens of millions smaller still….

• Hurtling around Earth at up to 18,000 mph.Enter, the CubeSat era:

In fact, it is thought that CubeSats account for <1% of orbital debris…

Who is responsible for the clear up?

….but in short, all parties launching spacecraft into LEO should have the moral obligation to ensure that they responsibly, and safely dispose of their craft at the end of its operational lifespan.

WARNING, FUZZY GREY AREA!!!

• ASI (Agenzia Spaziale Italiana)• CNES (Centre National d'Etudes Spatiales)• CNSA (China National Space Administration)• CSA (Canadian Space Agency)• DLR (German Aerospace Center)• ESA (European Space Agency)• ISRO (Indian Space Research Organisation)• JAXA (Japan Aerospace Exploration Agency)• NASA (National Aeronautics and Space

Administration)• ROSCOSMOS (Russian Federal Space

Agency)• SSAU (State Space Agency of Ukraine)• UK Space Agency

{Inter-Agency Space Debris Coordination Committee (IADC)

25 years is often thrown about as figure, but in reality this is a long time for something to cause a collision……..

What are the solutions?

Capture vs. Mitigation

AEOLDOSAERODYNAMIC END OF LIFE DEORBIT SYSTEM

• Passively deployed drag sail– Residual atmospheric particles generate

drag forces to reduce host spacecraft velocity.

– Double the projected area, halve the time to deorbit.

• Compatible to most commercially available CubeSat structures.

• Modular; can be either end stack or mid-stack mounted.

• Autonomous deployment achievable.• 0.4U – up to 3m2 radially symmetrical

sail.• Integrated button cell for deployment

activation (no power requirement from host).

• Low-cost; in-keeping with the CubeSat ethos.

{0.4U

Stored Strain – simple and elegant• Spooled tape-springs are a popular deployment

mechanism.

– Uni-stable structure due to its C-shaped cross section.

– Stores strain energy when wound into a spool.– Only requires electrical energy to initiate release.– Multiple booms can be wrapped around a single

spool.– Low-cost prototyping using COTS.

Other devices using tape-springs often deploy their booms tangentially…this can lead to a number of problems.

Radial Vs. Tangential Deployment

Petal Hub

Square Hub

Radial Vs. Tangential Deployment

Square Hub Petal Hub

Petal Hub

Sail Casting Doors and the InnardsSail casting doors in stowed position

Once the spool is released, the booms extend and the doors are cast outwards

Cage bearings force the booms to deploy radially

Petal Hub ensures safe and robust deployment

Sail stowage area

Symmetrically Folded Sail

Empty sail cartridge

Optimised folded sail

Fitted cartridge

Symmetrically Folded Sail

Real-time footage

High-speed camera footage

3D AEOLDOS – New Opportunities?Novel Bevel Crux Drive (BCD) that enables the symmetrical deployment of a 3D sail.

Utilises the already demonstrated tape-spring approach in combination with radially spaced bevel gears that communicate generated torques evenly throughout the assembly.Research focussing on using the BCD to effectively raise and lower the orbits of host spacecraft.

Thank you for listening…

please feel free to ask me questions at the end of the session…

….or contact me at Malcolm.McRobb@clyde-space.com