Reacción a "Reactions to study warning about risks of uncontrolled rocket re-entry"

This paper does not contain new data, facts, results, or concepts. Over the years, until very recent times, similar analyses, results and discussions have already been presented at international conferences, as those of the International Association for the Advancement of Space Safety, and published in technical journals, as the Journal of Space Safety Engineering, although all or most of this bibliography cannot be found in the references. Therefore, there is not much to comment on the figures provided, unless that they support previous findings. Legal and regulatory discussion has also been ongoing for a long time, and several proposals have been made, even relatively recently, to address the issue.

I limit myself to a couple of remarks. Currently, the global casualty expectancy due to uncontrolled reentries of rocket bodies accounts for more than 2/3 of the total, including spacecraft. But in the coming decade, the proportion of low altitude satellites compared with rocket stages will increase significantly, and at some point the combined risk of satellites, already about 1/3 of the total, is bound to prevail. So focusing the attention only on orbital stages is pointless, over the medium term.

The second remark concerns the risk. The casualty expectancy from uncontrolled reentries is currently low, and will remain so. If it can be considered negligible or not, it is just a matter of definition. Nevertheless, from a numerical point of view, the picture is very clear. Even ignoring the annual casualties due to treatable diseases, inadequate health care, famine and war, deaths attributable to accidents and pollution alone number in the millions worldwide. Looking, on the other hand, at the casualties expected from uncontrolled reentries of rocket bodies and satellites, we are still talking about a couple of victims a century, on average.

Therefore, while we all wish for even safer space activities than they currently are, the reentry risk is certainly not the most critical. The potentially adverse pollution of stratosphere and mesosphere from increased launch rates will probably need much more attention in the coming decades, even though I strongly support the adoption of stricter and binding regulations applied to the reentry of rocket bodies and satellites, and to space activities in general.