Re: STILL OFF TOPIC: Re: America needs therapy
Eugene Leitl wrote:
Problem is high LEO launch costs. It would seem easier to build automated and teleoperate fabbing and (linear motor) launching facilities on Luna, and circularize orbit mostly by aerobraking.
And if you can put up a bloody huge enough launcher on the moon, (use solar energy or nuclear - why not - it is one place in the system that we don't care about pollution) then you can send material back all the way to LEO by slingshot, and when it is captured by the facility at LEO, if you do it right, you can get a "free" boost in orbit because of greater orbital velocity of moon. So the more you accrete onto your LEO station the higher it flies. Why not make it the size of Wales? Hello Earth Station One. Well, 3 technically I suppose, Mir was One, the thing up there now is Two. Can't really count Skylab. There is a good fun fictional treatment of the lunar-driven space station idea by Donald Kingsbury "The Moon Goddess and the Son". Written before the Soviet Union fell. In the book they get done in by home-made cruise missiles built out of private planes & off-the-shelf, computers, autopilots, and GPS by Afghan refugees who studied aero engineering in Europe and the US. I think it might be worth re-reading. That and "Arslan" AKA "The Wind from Bukhara" by Madeleine (?) Engh. Ken Brown
At 02:00 PM 10/2/01 +0100, Ken Brown wrote:
And if you can put up a bloody huge enough launcher on the moon, (use solar energy or nuclear - why not - it is one place in the system that we don't care about pollution) then you can send material back all the way to LEO by slingshot, and when it is captured by the facility at LEO,
And Lloyds pays out when you miss the catch? (Then again, NASA played plutonium slingshot without coverage... )
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tuesday 02 October 2001 07:43 am, David Honig wrote:
At 02:00 PM 10/2/01 +0100, Ken Brown wrote:
And if you can put up a bloody huge enough launcher on the moon, (use solar energy or nuclear - why not - it is one place in the system that we don't care about pollution) then you can send material back all the way to LEO by slingshot, and when it is captured by the facility at LEO,
And Lloyds pays out when you miss the catch?
(Then again, NASA played plutonium slingshot without coverage... )
Bah. Read a physics text sometime. Miss the catch and the payload continues on in it's original path, which would be at a tangent to the intended orbit and therefore to the surface. As for NASA playing "plutonium slingshot", they did indeed - with a huge margin for error, and a design so pessimistic that even if the damned thing had slammed head-on into the planet, there would almost certainly have been zero contamination. If the canister HAD broken, the contamination would have been roughly on the scale of Three Mile Island, which killed 0 people and did 0 environmental damage. If you and the other idiots want to object to the things NASA and others do, fine. Be my guest. But do your homework FIRST. - -- Matt Beland matt@rearviewmirror.org http://www.rearviewmirror.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE7udl8BxcVTa6Gy5wRAu0AAJ93/TITE97kXPo52yd+5gjEJQqYLACfTZHb mplHm14BS0ZzA62i+DyW6go= =4cvG -----END PGP SIGNATURE-----
At 08:12 AM 10/2/01 -0700, Matt Beland wrote:
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On Tuesday 02 October 2001 07:43 am, David Honig wrote:
At 02:00 PM 10/2/01 +0100, Ken Brown wrote:
And if you can put up a bloody huge enough launcher on the moon, (use solar energy or nuclear - why not - it is one place in the system that we don't care about pollution) then you can send material back all the way to LEO by slingshot, and when it is captured by the facility at LEO,
And Lloyds pays out when you miss the catch?
(Then again, NASA played plutonium slingshot without coverage... )
Bah. Read a physics text sometime. Miss the catch and the payload continues on in it's original path, which would be at a tangent to the intended orbit and therefore to the surface.
Why don't you consider worst case scenarios, and aerobraking.
As for NASA playing "plutonium slingshot", they did indeed - with a huge margin for error, and a design so pessimistic that even if the damned thing had slammed head-on into the planet, there would almost certainly have been zero contamination. If the canister HAD broken, the contamination would have been roughly on the scale of Three Mile Island, which killed 0 people and
did
0 environmental damage.
Why don't you consider worst case scenarios, and aerobraking.
If you and the other idiots want to object to the things NASA and others do, fine. Be my guest. But do your homework FIRST.
Why don't you consider worst case scenarios, and aerobraking.
Once the catcher is high enough it ought to be possible to set the launcher so that missed catches zip round Earth & head out. After all, at Lunar OV it "wants" to be in a high orbit. Achieving re-entry through Earth's atmosphere - sorry that should be "entry" it wasn't here in the first place - needs some precision. And if the loads are anything smaller than a large truck, they ought not to harm Earth anyway. Just a pretty light show for anyone watching the skies. Nothing like as fast as natural meteors. Moon-Earth flight time could be days. As many days as you want I suppose as long as you are going faster than the Moon's escape velocity, and certainly very many hours. If you do it right there is no reason it couldn't pass the station at almost any required speed. Catching is the hard part. A plain ordinary net might have to do, at least at first. Well, not *that* plain or ordinary. But it needs to be light because it comes up from Earth. You have to start small, with pea-sized consignments. Or baked-bean-can-sized. Then you work up, making new equipment from stuff sent from the moon. Anything big enough to do damage on Earth will be visible from Earth. So it isn't at all a useful weapons launching system. If you are trying to drop big hot rocks on cities, they will have time to run away (low tech solution) or phone up their sub commanders and tell them to light the blue touchpaper (high tech solution). Same goes with knobs on for nukes. The way to get a station into higher orbits is to start even higher and drop stuff onto it from above. Ken Brown David Honig wrote:
At 02:00 PM 10/2/01 +0100, Ken Brown wrote:
And if you can put up a bloody huge enough launcher on the moon, (use solar energy or nuclear - why not - it is one place in the system that we don't care about pollution) then you can send material back all the way to LEO by slingshot, and when it is captured by the facility at LEO,
And Lloyds pays out when you miss the catch?
(Then again, NASA played plutonium slingshot without coverage... )
on Tue, Oct 02, 2001 at 05:19:09PM +0100, Ken Brown (k.brown@ccs.bbk.ac.uk) wrote:
Once the catcher is high enough it ought to be possible to set the launcher so that missed catches zip round Earth & head out. After all, at Lunar OV it "wants" to be in a high orbit. Achieving re-entry through Earth's atmosphere - sorry that should be "entry" it wasn't here in the first place - needs some precision.
The Heppenheimer book cited here previously posited a catcher fabricated out of bulletproof material, in lunar orbit. Of roughly conical form, and rotating about its axis, material launched via railgun from the lunar surface would be caught, then ferried to an L4 or L5 construction point. Heppenheimer's scenario envisioned using pellet shooters as reaction mass. Matter flux in orbit is such that operations could be carried out for extended periods of time with no perceptable increase in micrometeorite impacts.
And if the loads are anything smaller than a large truck, they ought not to harm Earth anyway. Just a pretty light show for anyone watching the skies. Nothing like as fast as natural meteors.
For loosly aggregated masses, possibly even larger: they'd simply disintegrate in orbit. Though try to justify the low odds to the poor sap who *does* happen to be in the wrong place.
Anything big enough to do damage on Earth will be visible from Earth.
Lunar material has an albedo of about 3%. Its radar signiture may be better. But there isn't currently a tracking system that's designed to detect large amounts of new orbit insertions. Yes, we track dead satellites, lost space hardware, and the odd glove. Hundreds of thousands of stone-tossings, I'm not so sure.
So it isn't at all a useful weapons launching system. If you are trying to drop big hot rocks on cities, they will have time to run away (low tech solution)
Cities can't run. Their populations can. But it would take a day or two for a typical US conurbanation. The infrastructure remains particularly vulnerable. Better yet: water strike. If you're particularly devious, aim for an unstable undersea slope seismic region. Heinlein's good history here, particularly if you're into harsh mistresses. Peace. -- Karsten M. Self <kmself@ix.netcom.com> http://kmself.home.netcom.com/ What part of "Gestalt" don't you understand? Home of the brave http://gestalt-system.sourceforge.net/ Land of the free Free Dmitry! Boycott Adobe! Repeal the DMCA! http://www.freesklyarov.org Geek for Hire http://kmself.home.netcom.com/resume.html [demime 0.97c removed an attachment of type application/pgp-signature]
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tuesday 02 October 2001 06:00 am, Ken Brown wrote:
Eugene Leitl wrote:
Problem is high LEO launch costs. It would seem easier to build automated and teleoperate fabbing and (linear motor) launching facilities on Luna, and circularize orbit mostly by aerobraking.
High LEO launch costs are just down payments. It's literally true, energy-wise, that LEO is halfway to anywhere in the solar system. What's needed is a group of intelligent people and a "seed stock" of technology on the Moon. Teleoperation is great technology, but what's the point in these endeavours without a human component? Besides, teleoperation and AI and everything else breaks down, and the more complicated a thing is the easier it is to break it. Wheras humans... well, Scott Carpenter's description of an astronaut was roughly something like "A nonlinear computer with over 1 billion binary decision elements, weighing less than 200 pounds, and capable of being produced by unskilled labor". A large enough human presence is self-repairing, self-replicating, and self-controlling. The perfect world for rapid expansion.
And if you can put up a bloody huge enough launcher on the moon, (use solar energy or nuclear - why not - it is one place in the system that we don't care about pollution) then you can send material back all the way to LEO by slingshot, and when it is captured by the facility at LEO, if you do it right, you can get a "free" boost in orbit because of greater orbital velocity of moon.
Backwards. Higher orbit == lower velocity. As each component is added, you increase the mass of the station. You increase the energy of the total structure because the new component carries with it kinetic energy realized from the decrease in altitude, but rendevous and docking will probably waste all of that advantage in braking burns. Your chief advantage is that it takes much less energy to get from the Moon's surface to LEO than it does to get from the Earth's surface to LEO.
So the more you accrete onto your LEO station the higher it flies. Why not make it the size of Wales?
Why would you want to? If it's the size of Wales and solar maximum begins to drag it lower, how in the hell would you boost it again without throwing away all of Swansea as fuel? Easier and cheaper to use lunar material to build stations and equipment in High Earth Orbit, GEO, and at the LaGrange points. Especially at L4 and L5, you could build your station as large as you want (O'Neill designed them as large as 30 km, IIRC) and never worry about the mass because it won't ever go anywhere.
Hello Earth Station One.
Well, 3 technically I suppose, Mir was One, the thing up there now is Two. Can't really count Skylab.
More like "11". Salyut 1 through 7, Skylab, Mir, and ISS or whatever the hell they're calling it this week. In terms of habitable volume, the Salyuts are the smallest, followed by Mir before expansion, then Skylab, then Mir after expansion, then ISS-as-designed. ISS-as-built is, I believe, somewhere between Mir and Skylab, although to be fair they aren't done yet.
There is a good fun fictional treatment of the lunar-driven space station idea by Donald Kingsbury "The Moon Goddess and the Son". Written before the Soviet Union fell. In the book they get done in by home-made cruise missiles built out of private planes & off-the-shelf, computers, autopilots, and GPS by Afghan refugees who studied aero engineering in Europe and the US. I think it might be worth re-reading. That and "Arslan" AKA "The Wind from Bukhara" by Madeleine (?) Engh.
And for serious-but-light reading on the topic, look for "Colonies In Space" by Heppenheimer, "The High Frontier" by Dr. O'Neill, and more recently "Entering Space" by Zubrin. The first two are wildly optimistic, the last is actually rather pessimistic - I could argue with the numbers of all three, and reality is probably somewhere in the middle. The three also increase in technical detail and decrease is "fun" as you go down the list. - -- Matt Beland matt@rearviewmirror.org http://www.rearviewmirror.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE7udh2BxcVTa6Gy5wRApBXAKD8DZgGMYM6lN4INfdfIb1hDD9oNQCePxQS 5JsNNwbde1TeI952dsXGDJw= =3taz -----END PGP SIGNATURE-----
participants (4)
-
David Honig -
Karsten M. Self -
Ken Brown -
Matt Beland