Thread by @ProfHughLewis

For a recent assignment on #spacedebris, I asked undergraduate & postgraduate students to evaluate the benefits & risks of a LEO (NGSO) constellation & to say whether approving a license application was merited. Here's a thread about what they said:

Of the 38 students participating, 58% thought that approving such a licence application was merited, 24% thought more analysis was needed & 18% thought that denying the license application was the correct action.

Some of the positive points identified wrt NGSO proposals were:
1. Providing internet access to remote regions & those lacking terrestrial infrastructure.
2. Meeting or exceeding expectations wrt #spacedebris mitigation guidelines.
...

3. Avoiding RF interference with other providers.
4. Advocating for #SpaceSustainability.
5. Innovative solutions for managing conjunctions with other orbiting objects.
6. Proactive & early disposal of satellites with faults.
7. Designed for demise.

Some of the negative points identified were:
1. Reliability of satellites (& that so much depends on this).
2. High manoeuvre burden for the operator & operators of other spacecraft traversing the constellation.
3. Optical & RF brightness of the satellites.
...

4. Economic stability/resilience of the operator.
5. Inconsistent approaches to regulation globally.
6. Accuracy/trustworthiness of models used to evaluate #spacedebris risks.
7. High consumer costs.
8. De facto ownership of key orbital altitudes.
9. Conflicts of interest.

It was also interesting to see some biases in the student responses that can also be found in published studies (some I admit to) & in stories in the media:

1. Basing estimates of satellite reliability or likely success of #spacedebris countermeasures on different & sometimes decades-old space systems.

If you wanted to purchase a new phone, would a poor experience with an old [brand X] model mean that you would avoid a new [brand Y] model?

2. Confusing "lower" or "less" with "low". Some NGSO systems are aiming for LEO altitudes where the spatial density is "lower" than the current peak spatial density at 800 km. Nonetheless, the spatial density is not necessarily "low".

3. The implications for long-term #SpaceSustainability are all that matters. At some of the proposed altitudes, these new NGSO systems will not pose a long-term hazard but there will still be implications for #SpaceTrafficManagement.

4. Adding a "mega-constellation" will trigger the Kessler Syndrome. I have written about this one already. The sad reality is that current space activities are already taking place in the context of a #spacedebris population that is growing uncontrollably (perhaps for now)...

...so the Kessler Syndrome ship has sailed. Several mega-constellation operators have recognised a way to limit the long-term impacts of their activities is to aim for altitudes below about 600 km. This will be effective (as long as the atmosphere continues to help us)...

...but it still requires careful analysis & work to reduce the #SpaceTrafficManagement burden.

Overall, I am really proud of my students. Collectively, they identified the key issues being driven by, and facing, mega-constellations. They understood the potential benefits but saw the compromises needed to make them a reality.

I also learned a lot by reading what my students had to say. They will soon be young professionals in the space industry with ambitions & talents to match. But they will also have an awareness of the #spacedebris challenges that lie ahead if we are to succeed in space.

It's also been good to gain insights into the challenges faced by the operators & the regulators. There is no easy way through. Until we have a "vaccine" for #spacedebris, we are going to have to learn to live with it for some time.

End.