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Striving for Precision SSA


The need for improved situational awareness of the space operating environment, or “SSA”, is growing, with over 95% of the predicted population of objects larger than 1 cm continuing to elude existing space surveillance and tracking systems, and catalogues that are, despite this, swelling with new additions, active and derelict alike.

On Wednesday 9th March 2022, GNOSIS will be running a sandpit event on “Precision SSA”, following on from the corresponding workshop that took place in July 2020. The sandpit will look to generate further discussion on the topic, with the aim of sparking collaborations that could potentially be supported by GNOSIS funding opportunities.

While the title places focus on precision, the programme will also take into consideration timeliness, accuracy, and completeness; all vital to achieving sustainable operations in space, and each associated with a host of challenges to overcome.

The original workshop identified a wide range of inadequacies in current SSA capabilities, relating to both legacy and contemporary problems, and showcased state-of-the-art efforts to tackle them:

  • Insufficient force modelling can result in large propagation uncertainties, a particular issue when attempting to maintain custody of satellites making use of low-thrust, long-duration electric propulsion for transfer between GTO and GEO, or indeed those under the influence of any non-Keplerian perturbation(s), such as atmospheric drag and solar radiation pressure.
  • Tracking and association algorithms often struggle to cope with sparse datasets from surveillance systems that are coming under increasing strain.
  • Operators frequently lack the timely, accurate and precise positional measurements required to make suitably informed decisions when faced with conjunction warnings. Furthermore, more sophisticated algorithms for assessing collision risk are needed, to make the most of the data available. This combination of factors typically gives rise to conservative collision avoidance strategies, that can lead to the rapid depletion of onboard propellant and thus to significantly reduced operational lifetimes. With a growing catalogue, this problem is only set to become more prevalent.
  • In-orbit servicing, active removal, and other missions involving rendezvous and proximity operations will necessitate precision SSA to preserve the safety of service/client satellites during close approach and docking activities.
  • Precision data will be required to inform the development of improved algorithms for object detection, classification, and characterization. The fusion of such data from a variety of existing and novel instruments and techniques will also be important.
  • The same is true for datasets that feed into the quasi-deterministic models of the debris environment that are used to predict the levels of risk posed to prospective spacecraft by orbital debris, and to inform strategies for future debris mitigation practices and remediation missions. Precision SSA will play a major role in probing the population of small debris that has arisen from the hundreds of fragmentation events that have taken place since the dawn of the Space Age, the key to addressing the concerningly large discrepancies that currently exist between the outputs of leading environmental models.

The programme for the March sandpit will touch on many of these areas, featuring an exciting line-up of talks from experts in academia and industry. Registration is now open via the event webpage, where the latest programme details can be found.

[Image credit: Mark Garlick/ Centre for Space Domain Awareness, University of Warwick, UK].

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