Disposal of satellites require better strategies to reduce 'casualty risk', reveals Study

Space debris has emerged as one of the major threats that face the orbiting satellites, observatories like the Hubble telescope and laboratories like the International Space Station. However, the satellites that are considered prone to space debris are themselves a threat to people on Earth, as per a new research.

Titled, "Re-Entry Prediction and Demisability Analysis for the Atmospheric Disposal of Geosynchronous Satellites," the study argues that space companies now need to reconsider how they dispose off their satellites to minimise “casualty risk” for other satellites and for people on Earth, reported The Science Times.

What are the different levels of satellite orbits?

A report by Interesting Engineering revealed that the study emphasises the development of a proper strategy by space organisations regarding the safe disposal of satellites deployed at various levels in the orbit.

The different levels of the orbit include the Low-Earth Orbit (LEO), Geosynchronous Orbit (GSO), Medium Earth Orbit (MEO), and Highly Elliptical Orbit (HEO). As a result of high activity by space companies in recent years, the LEO and GSO have become the most populated ones.

In fact, the LEO has become a go-to option for the majority of space organisations as the deployment of satellites requires a low cost and operations such as remote sensing, Earth observations, and telecommunications become easy. However, this advantage also comes with a curse as the LEO has become the region with the most number of inactive satellites. This increase in the number of debris that revolve at excessive speeds in the orbit poses a risk of satellite collision, which might even follow a trajectory that ends up in a crash on Earth. 

Satellite re-entry and its risks

Although the satellites in the LEO get destroyed easily while re-entering Earth during disposal, it is the deorbiting and disposal of satellites in the GSO, MEO and HEO that require more complex strategies.

The experts reportedly analysed the on-ground casualty risk of disposing of satellites via re-entry using software called "Phoenix". After combining the data of casualty area - the region in the sky where a satellite breaks into pieces during re-entry and scatters, impact locations and areas habited by people.

The results by Phoenix showed that the trajectories planned by space companies for satellite re-entry showed a high risk of casualty and thus emphasised that 'the application of design-for-demise techniques, or controlled and semi-controlled re-entries would be necessary' as per Interesting Engineering.

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