Abstract:
There is an increasing amount of debris in low Earth orbit arising from the
disintegration and collision of old spacecraft which have not been removed from
orbit. A ‘bolt-on’ deorbit device to be attached to new spacecraft is therefore
proposed, which would deploy an aerostable drag sail at end-of-life. This drag sail
would interact with the rarefied atmospheric gases and plasma present at altitudes of
up to 1,000 km and thus denude energy from the orbit, causing it to become lower
and lower until final re-entry of the host becomes inevitable. At this point the drag
sail would collapse and both the host and the deorbit device would be destroyed by
aerothermodynamic forces.
This work develops the deorbit device concept by demonstrating that aerostable drag
enhancement is an effective and competitive deorbit mechanism. This is done by:
• Calculating the aerodynamic, solar radiation pressure and gravitational
influences on the deployed drag sail and using them to model the
performance of the device.
• Using the results of that modelling to identify the optimum shape, size and
deployment conditions of the drag sail.
• Further calculating the structural strength required to resist the aerodynamic
loads until the desired collapse altitude.
• And finally by using that information to assemble a conceptual design which
demonstrates the practicability of the system.
