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journal
Journal
by
RockDoctor
y March 27, 2021 @07:37AM
Arxiv 2103.13304 "Automatic planetary defense : Deflecting NEOs by missiles shot from L1 and L3 (Earth-Moon)" proposes that
●-1- hitting a PHA at 90deg to it's orbit is most likely to produce a large course change. I think that's pretty obvious once you look at it.
●-2- this can be achieved at more manageable cost from L1/ L3, which are always in sight of Earth (radio communications). An elliptical orbit CONFOCAL (having the same focal points as) to the PHA's hyperbolic orbit will intersect the PHA at 90deg. I'm not entirely sure what the L1/ L3 brings to it other than relative stability and line-of-sight.
●-3- there remains the problem of determining the PHA's orbit sufficiently accurately sufficiently soon. Time-of-flight from L1/ L3 to half-way across the Earth-Moon system remains significant, O(1day).
●-4- Launching a salvo of missiles would produce lower risk-of-miss.
●-5- Wouldn't a missed missile return to (close to) L1/ L3, potentially for re-use or re-fuelling?
●-6- If so, why not produce a stream of orbiting missiles needing relatively small course adjustments to reach a PHA, so approximating a permanent defence system?
●-7- doesn't the L1 Sun-Earth point present the same benefits ... no, we're looking at PHAs which may impact the central body, and we don't care about rocks hitting the Sun.
●-8- You'd need two streams of missiles in clockwise/ counter-clockwise orbits to reach most orbits efficiently. Would you need some at moderate inclinations to cover out-of-Fundamental Plane objects? Or ... the contra-rotating missile streams being at 45deg to the Fundamental Plane to cover both options.
●-9- Somewhat related, what would be the benefits of Earth-Sun L4/ L5 points for positioning earth-scanning telescopes to scan for PHAs.
●-n-
The detailed paper (Acta.Astro 50 185 (2002) is hidden and SciHub blocked now. Asked author for a copy (ore re-post yo Arxiv?). Need a VPN.
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The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
bychill ( 34294 ) writes:
You mean this [dwimports.net]? The 13-page PDF?
byRockDoctor ( 15477 ) writes:
Looks like it - or doesn't, through Firefox's PDF rendering error. I wonder what triggers those, but I've only guessed that its an absence of fonts, and Sumatra (or evince) does a better substitution job than Firefox's rendering engine?
I've not used /.'s "journal" system much - I'm experimenting with it for composing and working on potential submissions. You're right, I should have included a link to the Arxiv posting [arxiv.org]. IIUC, journal notices go to people on my "friends" list, but not the rest of the world.
bychill ( 34294 ) writes:
I misread your original post in that you couldn't get to Arxiv or the document anymore. I downloaded it thru a VPN (Czechia) and posted it on my personal server so you could grab a copy.
I'm going to remove it as that wasn't the case.
byRockDoctor ( 15477 ) writes:
It's the Acta.Astron. paper of 2002 (which by implication has the code for describing the orbits) which I can't get to. Normally I'd SciHub it, but the SciHub sites seem to be being blocked (DNS poisoning at my ISP, or their national backbone provider? I don't know.) So I'm thinking I may need to get a VPN for that. Or Tor it.
bychill ( 34294 ) writes:
Ah, then here you go: http://dwimports.net/maccone2002.pdf [dwimports.net]
And check out these guys [best-hosting.cz]. They charge like $70 / year to host a Raspberry Pi. I configured one with PiVPN [pivpn.io] and now have my own, personal, VPN server in Czechia for when I don't want to deal with U.S.-regional annoyance.
They will sell you one, or you can ship your own over. Much better than some commercial VPN service, where all the major ISPs have a list of their endpoints. With one of these, you're just another server in Europe and not on someone's b
byRockDoctor ( 15477 ) writes:
Hmmm, interesting.
I'll give that a serious thinking about. My own RPi server in an anonymous rack somewhere. Interesting.
Being unemployed and living off my savings, $70/year is noticeable, but it's still a good price. Last time I looked at it (LPredator.Se, run by graduates from the School of PirateBay Lawsuits), they were charging something similar. But I might just run a TOR memory stick off a convenient box. I've started building my own NAS recently (the mini-desktop is under the sofa, under me, at thi
byRockDoctor ( 15477 ) writes:
I dropped another "in work" from Arxiv onto the journal as well. I get an email from them daily (actualy an offshoot called IArxiv, which trains an AI to rank today's new Arxiv postings according to your previous selections to read - which is scarily effective. So scarily effective that I routinely look at the list from low-ranking to high-, so I'm likely to see the unusual-to-me stuff.
You're a more general computing dude than my rocks/ stars focus. Do you think that sort of AI in itself is good fodder for
bychill ( 34294 ) writes:
Maybe.
Over the last couple of years I've seen several stories about AI used to generate word-salad papers that glide through peer-review. Mostly it exposes the fraud of "make up a serious-sounding journal name and get it on your resume". The use of AI to QC some of that would be a good counterpoint. Maybe with a side-bar on how it isn't used to blindly reinforce the orthodoxy, but still to assist in rooting out the obviously flawed stuff to lighten the workload of the dedicated peers.
But, if you're talking
byRockDoctor ( 15477 ) writes:
word-salad papers that glide through peer-review
That must be pretty shoddy "peer review". Most of the time when I see academic scientists complaining about having a paper in for review, they're saying it's around 4 hours - half a working day - work. Which today would be priced at £400-600. The actual payment is rarely any different to £0.
I've just put an hour into reading that Maccone paper (boo - little in it that wasn't in the one I saw a few days ago on Arxiv), and if I were to b
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