Author Topic: Uncontrolled rockets pose unnecessary risk, study finds  (Read 2523 times)

Offline su27k

  • Senior Member
  • *****
  • Posts: 5837
  • Liked: 8380
  • Likes Given: 798
https://www.theverge.com/2022/7/11/23199088/uncontrolled-rocket-reentry-casualty-risk-analysis-space-industry

Quote
What are the odds a free-falling rocket will kill one person somewhere in the world? There’s about a 10 percent chance over the next decade if current practices in the space industry stay the same, according to the authors of a new paper published in the journal Nature Astronomy.

While that’s not a huge risk, the threat is significantly bigger in some parts of the world than in others. In particular, many countries in the Global South are likely to deal with a larger share of space trash even though they’re not responsible for it, according to the analysis. And it could become a bigger issue as rockets launch into space more frequently to ferry up a growing number of satellites.

“It’s a statistically low risk, but it’s not negligible, and it’s increasing — and it’s totally avoidable,” says Michael Byers, lead author of the analysis and a professor in the Department of Political Science at the University of British Columbia. “So, should we take available measures to eliminate casualty risks? I think the answer should be yes,” he says.

Offline edzieba

  • Virtual Realist
  • Senior Member
  • *****
  • Posts: 4427
  • United Kingdom
  • Liked: 6458
  • Likes Given: 35
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #1 on: 07/20/2022 11:49 am »
Skip the Verge's hamfisted summary, actual paper is here (open access): https://www.nature.com/articles/s41550-022-01718-8

Online artume

  • Member
  • Posts: 4
  • Liked: 7
  • Likes Given: 0
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #2 on: 07/20/2022 11:52 am »
A quick skim shows that the authors assume that "each reentry spreads lethal debris over a 10m2 area". Does anyone know what proportion of reentry results in debris reaching the ground instead of breaking up in the atmosphere?
« Last Edit: 07/20/2022 11:52 am by artume »

Offline edzieba

  • Virtual Realist
  • Senior Member
  • *****
  • Posts: 4427
  • United Kingdom
  • Liked: 6458
  • Likes Given: 35
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #3 on: 07/20/2022 12:10 pm »
A quick skim shows that the authors assume that "each reentry spreads lethal debris over a 10m2 area". Does anyone know what proportion of reentry results in debris reaching the ground instead of breaking up in the atmosphere?
I went looking through the references for that, too. Closest is https://doi.org/10.2514/1.30173 which notes a more conservative 70 m^2 casualty area, for a DCSS entry. Possibly this was mass normalised across the distribution of rocket bodies in orbit (most will not be that large) to give the more optimistic 10 m^2 figure.

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 35723
  • Minnesota
  • Liked: 19888
  • Likes Given: 10368
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #4 on: 07/20/2022 12:41 pm »
https://www.theverge.com/2022/7/11/23199088/uncontrolled-rocket-reentry-casualty-risk-analysis-space-industry

Quote
What are the odds a free-falling rocket will kill one person somewhere in the world? There’s about a 10 percent chance over the next decade if current practices in the space industry stay the same, according to the authors of a new paper published in the journal Nature Astronomy.

While that’s not a huge risk, the threat is significantly bigger in some parts of the world than in others. In particular, many countries in the Global South are likely to deal with a larger share of space trash even though they’re not responsible for it, according to the analysis. And it could become a bigger issue as rockets launch into space more frequently to ferry up a growing number of satellites.

“It’s a statistically low risk, but it’s not negligible, and it’s increasing — and it’s totally avoidable,” says Michael Byers, lead author of the analysis and a professor in the Department of Political Science at the University of British Columbia. “So, should we take available measures to eliminate casualty risks? I think the answer should be yes,” he says.
A professor of political science?

10% risk of one random fatality is crazy low!

It’s estimated that about every 4000 tons of CO2 emissions will lead to one extra climate death, again mostly folks in the global south.That’s like just 10 777 flights. Seems to me cost per fatality avoided would be several orders of magnitude better if we focused on CO2 emissions reduction.
« Last Edit: 07/20/2022 04:39 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 35723
  • Minnesota
  • Liked: 19888
  • Likes Given: 10368
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #5 on: 07/20/2022 12:47 pm »
Anyway, it’s a good argument for reusable rockets which don’t have uncontrolled, random reentry (either intentionally or unintentionally, as RLVs can reach higher reliability). They can even recover large satellites at end of life before they reenter (smaller satellites can be fully demisable).
« Last Edit: 07/20/2022 12:48 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline spacediver

  • Member
  • Full Member
  • *
  • Posts: 125
  • Liked: 17
  • Likes Given: 0
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #6 on: 07/20/2022 12:49 pm »
This will be no Problem for the future as launch vehicles will become more and more reusable!
Example: www.spacecoptersystems.com

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 35723
  • Minnesota
  • Liked: 19888
  • Likes Given: 10368
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #7 on: 07/20/2022 04:45 pm »
This will be no Problem for the future as launch vehicles will become more and more reusable!
Example: www.spacecoptersystems.com
I love the design! I’ve had similar ideas for years, now, and I wish them luck!

It doesn’t look like a rocket, but because the atmospheric density at 12000m is about a quarter that of sea level, it doesn’t need to. It would have similar aero drag (per unit mass) as a vehicle 4 times taller at the same density and diameter, plus better Isp and better potential energy. Being essentially a three stage rocket (first stage being electric), with small expendable upper stage, it should be a fairly doable design without too aggressive performance.

I saw a little cheap electric hobby drone demonstrate a flight to 12500 meters (in Russia) breaking the record for helicopter flight, so this is a feasible thing to do and probably a better idea than launch assist on a 747 or something.

(The Ingenuity drone flies in Mars’ atmosphere, which is about comparable to flying at 100,000 ft on Earth, or given the higher gravity, maybe 80,000ft or 25km, so in principle you could double the electric assist altitude, which would mostly be helpful for reducing drag losses on the way up for such a small rocket. But a good case can be made of diminishing returns or need for multiple electric drone stages beyond the 12km proposed altitude.)
« Last Edit: 07/20/2022 04:52 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline freddo411

  • Full Member
  • ****
  • Posts: 899
  • Liked: 1031
  • Likes Given: 3029
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #8 on: 07/20/2022 04:54 pm »
Skip the Verge's hamfisted summary, actual paper is here (open access): https://www.nature.com/articles/s41550-022-01718-8

Conclusions not supported by the data

Reentry risks are highly distributed and not concentrated in the “south”, or in developing countries.  The paper’s data makes this clear


Not clear is the relative risks of various launch vehicles. Unfortunately, the paper estimates all vehicles as the same, lumping heavy together with cube sat launchers.

Another bias is the unsupported assertion of 1% population growth ..

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 35723
  • Minnesota
  • Liked: 19888
  • Likes Given: 10368
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #9 on: 07/20/2022 05:01 pm »
Probably an explanation is the political science professor trying to make hay of this. “What if rich countries go to space and screw over the “Global South?””

Assumptions have to be adjusted (unfavorably) until a scary conclusion is reached.
« Last Edit: 07/20/2022 05:01 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 35723
  • Minnesota
  • Liked: 19888
  • Likes Given: 10368
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #10 on: 07/20/2022 05:19 pm »
So I read the short paper, and it’s absurd. It’s clear they already had a narrative they wanted to tell and made assumptions to maximize that.

For instance, they make the claim that the launches of the future will mostly be geosynchronous, which is already false (and this is the only place where they could claim the “global south” is disproportionately at risk… because higher inclination LEO launches, like for megaconstellations, actually put mid-latitudes more at risk). They imply that most rocket launches don’t do controlled reentry already, which is also false. And they ignore totally the possibility that most future rockets will have reusable (and therefore recovered) upper stages.

They wanted to make a political point and so they made up some math with cherry-picked data and knowingly false assumptions to justify that narrative, even though the narrative doesn’t fit.

It also patronized the “Global South” by implying they wouldn’t be significantly spacefaring. In fact, for obvious reasons, they have fundamental advantages for launching to orbit compared to high latitude countries and may eventually benefit disproportionately from spaceflight. Indonesia has had its geosynchronous satellite launched by SpaceX.

Heck, China is grouped in with the “Global South,” and they are disproportionately a CONTRIBUTOR to such uncontrolled reentering rocket bodies. This is a massive narrative violation, of course, but don’t let that stop a political science professor from the point they’re trying to make…
« Last Edit: 07/20/2022 05:23 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline edzieba

  • Virtual Realist
  • Senior Member
  • *****
  • Posts: 4427
  • United Kingdom
  • Liked: 6458
  • Likes Given: 35
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #11 on: 07/20/2022 06:29 pm »
You appear to have misread the paper entirely:
For instance, they make the claim that the launches of the future will mostly be geosynchronous, which is already false
Fig.2 showing the projected rocket body distribution shows a significant expected decrease in equatorial objects, not an increase - expected due to fewer geostatioanry launches and continued decay of existing low-inclination objects with a low perigee.
Quote
(and this is the only place where they could claim the “global south” is disproportionately at risk… because higher inclination LEO launches, like for megaconstellations, actually put mid-latitudes more at risk).
Low latitude risk is higher due to higher population density (see Fig. 3). Some confusion may arise that Global South does not mean "latitudes below the equator".
Quote
t also patronized the “Global South” by implying they wouldn’t be significantly spacefaring. In fact, for obvious reasons, they have fundamental advantages for launching to orbit compared to high latitude countries and may eventually benefit disproportionately from spaceflight. Indonesia has had its geosynchronous satellite launched by SpaceX.
As your own example demonstrates, just being equatorial is not a significant advantage for spaceflight compared to other economic factors. Nusantara Satu flew from the US at 28.4°N, not from Indonesia at 0°. Even Sea Launch, which attempted to sidestep the socioeconomic barrier by building and integrating in the US and then relocating to the equator did not offer a significant value prospect from the equatorial delta V advantage. Not having or being able to afford to create an aerospace industrial base trumps being closer to the equator, just as it has for the last half century of spaceflight.

::EDIT::
For people with issues with the methodology rather than "social science is bad", the source data and calculations are available here: https://github.com/etwright1/uncontrolledrocketreentries
« Last Edit: 07/20/2022 06:31 pm by edzieba »

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 35723
  • Minnesota
  • Liked: 19888
  • Likes Given: 10368
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #12 on: 07/20/2022 08:41 pm »
The biggest blunder so far is Not the analysis, but the narrative of the global south being disproportionately at risk and not being the cause of the risk, which is absurd as China is the largest country in the Global South and also the worst contributor to this problem recently. Nice that the conveniently don’t mention that the Chinese launcher in their example IS a country in the global south!
« Last Edit: 07/20/2022 08:42 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline deltaV

  • Full Member
  • ****
  • Posts: 1602
  • Change in velocity
  • Liked: 211
  • Likes Given: 785
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #13 on: 07/21/2022 02:57 am »
This paper is sorely missing a cost-benefit analysis. A cost-benefit analysis would probably show that the proposed mitigations are horribly overpriced. Let's suppose the mitigations cost $1M / year, which is a very low estimate - just the extra paperwork to prove compliance could cost that much even if the changes didn't cost anything. If mitigations reduce payload capacity by even 1% the cost is orders of magnitude greater than $1M / year. Let's suppose the mitigations reduce the ~0.1 lives per decade from the paper by 90%. The cost per life saved is then $1M / (0.1 / 10 * 0.9) = $111M. That's ~10 times more than the usual cost per life used by US federal regulators. That cost per life saved is ~25,000 times more expensive than the $4500 per life saved for anti-malaria nets in Guinea (https://www.givewell.org/cost-to-save-a-life). Reducing uncontrolled reentries is a very, very bad way to go about saving lives.

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 35723
  • Minnesota
  • Liked: 19888
  • Likes Given: 10368
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #14 on: 07/21/2022 12:34 pm »
Well, the Global North ALREADY does these mitigations, and fully reusable rockets will necessarily have to have such “mitigations” in order to recover the upper stage, so there is no extra cost involved. It’s ironically only the “Global South” (China) that actively ignores such mitigations.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline edzieba

  • Virtual Realist
  • Senior Member
  • *****
  • Posts: 4427
  • United Kingdom
  • Liked: 6458
  • Likes Given: 35
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #15 on: 07/21/2022 02:27 pm »
Well, the Global North ALREADY does these mitigations, and fully reusable rockets will necessarily have to have such “mitigations” in order to recover the upper stage, so there is no extra cost involved. It’s ironically only the “Global South” (China) that actively ignores such mitigations.
Only to some extent, and only by 'self policing'. We have the Proton, Soyuz, and Angara upper stages that rarely perform deorbit burns. Atlas, Falcon and Delta upper stages that often do not perform deorbit burns (e.g. due to operating at payload limits, or attempting to minimise GTO residual delta-V), or attempt to but fail-unsafe. Ariane 5 has a non-restartable upper stage, so can only attempt deorbit by use of passivation venting (https://www.hou.usra.edu/meetings/orbitaldebris2019/orbital2019paper/pdf/6090.pdf) if the orbit allows.

There appears to be little pushback to proposals on requiring satellites to have some provision for end-of-life disposal or graveyarding (e.g. via atmospheric drag), it does not seem in any way unreasonable to apply the same to upper stages. If, as you claim, this is 'already done' with 'no cost involved' then it should be a nonissue to make it an explicit requirement rather than a mere implicit hope for new vehicles.

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 35723
  • Minnesota
  • Liked: 19888
  • Likes Given: 10368
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #16 on: 07/21/2022 02:35 pm »
It is a non-issue to do it. It comes free with reusable rockets (a pretty important fact not mentioned in the paper or article) and it’s silly to keep using expendable rockets. I would be happy to eventually make reusable and recoverable rockets a requirement.

The idiocy is someone trying to wag their fingers at the “Global North” and trying to score a geopolitical/sociopolitical hit when they ignore the facts and the trends in the aerospace world, ascribing malice to the most responsible figures in the field.

Social media (and thus the media) picks up this stuff and tries to make it look like advancing spaceflight is bad. Ignoring that the trend toward reuse that is enabling much of this spaceflight expansion is actually a complete solution to the proposed problem and it’s actually the Global South (well, China) that is most of the problem.
« Last Edit: 07/21/2022 02:40 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline jstrotha0975

  • Full Member
  • ****
  • Posts: 420
  • United States
  • Liked: 256
  • Likes Given: 1977
Re: Uncontrolled rockets pose unnecessary risk, study finds
« Reply #17 on: 07/21/2022 03:26 pm »
Breaking news: Water is wet. :D

Tags:
 

Advertisement NovaTech
Advertisement SkyTale Software GmbH
Advertisement Northrop Grumman
Advertisement
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1