Conquering the LaGrange Points? 911
3laws_safe writes "For decades, people have dreamed about building colonies at the five LaGrange points, intersections in space where gravitational and centrifugal forces balance out to provide orbital stability. But now, the official magazine of the U.S. Space Command advocates seizing control of the LaGrange points before other nations do it. From the article: 'We face the need to control the chokepoints of the solar system.' Arthur C. Clarke, who depicted a LaGrange colony in his classic 1961 novel A Fall of Moondust, is not very happy about this. He argues we should not 'export national rivalries beyond the atmosphere.' Is he right? Or should we prepare for the fact that such rivalries are inevitable, even in space?"
Interesting... error though (Score:1, Informative)
Re:France (Score:5, Informative)
Re:Chokepoints?? (Score:3, Informative)
Try studying orbital mechanics sometime, then repeat that for us.
You can't just fly around any direction you like in space. Your path is determined by the bodies of which you're orbiting. Chose one orbit and you'll get there faster, again at the cost of fuel. Chose another orbit and you'll get there slower but with more fuel. Chose the wrong orbit, and you won't get there at all.
When the predictions of "space can't be militarized" were made, powerful computers did not yet exist. No one considered that every possible orbit could be computed in real time with a gizmo that can fit in your pocket.
For the unaware (Score:1, Informative)
Re:Dimensions (Score:3, Informative)
If you are slightly off in any direction, you'd 'fall' further in that direction, it is more like the top of a mountain than like the bottom of a valley.
In practice, any craft or station placed on such a point would need thrusters to stay in place, unpowered it would drift (due to solar wind, particle impact, air leaks and what not) and start 'falling'.
I guess the region where you can reasonably compensate against falling would be quite large, depening on thruster output, weight and fuel reserves. Even if it were a sphere with a radius of 10 km, this would be a huge volume of space, and could hold many ISS-sized stations and or comsats.
No Such Thing As Centrifugal Force (Score:2, Informative)
The exact name is Lagrange (Score:2, Informative)
Re:Dimensions (Score:3, Informative)
The L4 & L5 points are 60 degrees plus and minus along the moons orbit around the sun. Due to the perturbations caused by the sun and other objects, the precise points are not stable. However, they forces on an object there would be fairly regular, so that it would fall in a kidney shaped orbit on the order of 80,000 miles long around the point.
Re:Only FIVE such points? (Score:5, Informative)
There are exactly and only five Lagrange points in any pair of orbiting bodies. Three are unstable and two are stable.
http://www.physics.montana.edu/faculty/cornish/la
Silly Question (Score:2, Informative)
In theory any craft not exactly in the middle will drift over time, but considering the forces involved here and other logistics, small thruster adjustments could easily compensate.
POTD (Pointless Question of the Day)
C'mon, spell it right (Score:5, Informative)
It's not capitalized oddly. It's just spelled Lagrange. As in, Joseph Louis Lagrange.
Re:Dimensions (Score:5, Informative)
L3 is unstable on a timescale of 150 years. That is, it's pretty stable for satellites, just not for planetary bodies. Of course, it also happens to be a friggin' useless orbit, as it never has line of sight visibility with Earth.
L4 and L5 are stable, so long as the mass of the larger object is greater than 24.96 times the mass of the smaller object. (Yes, it's really that odd number: it's actually 25*((1+sqrt(1-4/625))/2) ).
L4 and L5 are actually strange. They don't act like classical stability points, like most people think. If you push something away from L4/L5, it doesn't come back to L4/L5. It does, however, begin to orbit L4/L5, and those orbits are stable.
apparently, there is already a whorehouse there. (Score:3, Informative)
Rumour spreadin' a-'round in that texas town
'bout that shack outside la grange
And you know what I'm talkin' about.
Just let me know if you wanna go
To that home out on the range.
They gotta lotta nice girls.
Have mercy.
A haw, haw, haw, haw, a haw.
A haw, haw, haw.
Well, I hear it's fine if you got the time
And the ten to get yourself in.
A hmm, hmm.
And I hear it's tight most ev'ry night,
But now I might be mistaken.
Hmm, hmm, hmm, hmm.
Have mercy.
- billy gibbons, dusty hill & frank beard
Re:Chokepoints?? (Score:3, Informative)
This makes the Lagrange points ridiculously useful for future cargo transit through the Solar System. Transfers on the Interplanetary Superhighway cost almost no energy whatsoever. So you could easily imagine staging points at the Lagrange points of several major bodies, holding probes or cargo until a proper path opens up, and then sending something off.
The Genesis mission was one of the first to take an Interplanetary Superhighway path. (Honestly, those orbits drive me nuts. I understood Hohmann transfer orbits. I liked the fact that they were lowest energy. It was obvious. And then while I was still in classes, someone had to come along and prove the whole thing wrong.)
Re:Dimensions (Score:3, Informative)
It's usually called a tether not a motor, and it pushes againsts the earth's magnetic field to generate lift.
Not a huge amount of lift, but more than enough to maintain or even increase a low earth orbit.
Here's a link - http://www.tethers.com/EDTethers.html [tethers.com]
-- Should you believe authority without question?
L1 is occupied (Score:3, Informative)
As well as L2 (Score:3, Informative)
Re:No Such Thing As Centrifugal Force (Score:2, Informative)
Perhaps you need a force refresher course:
http://hyperphysics.phy-astr.gsu.edu/hbase/corf.h
Re:Dimensions (Score:3, Informative)
It's a little too technical. Though it is interesting that they don't have the timescales - I might add those. It's also interesting that one of the pages Wiki links to screws up days and years (http://www.physics.montana.edu/faculty/cornish/l
Re:L1 is occupied (Score:4, Informative)
Just because there's one thing there doesn't mean there can't be others. Plus, the ones we're mentioning here are just the solar Lagrange points. The lunar Lagrange points are all unoccupied (as far as I know...). The lunar L1/L2 are terrific places for a cheap, easy to build space elevator.
Re:For God's sake!! (Score:2, Informative)
Re:Yes (Score:4, Informative)
Re:Dimensions (Score:3, Informative)
Actually, 10, and they're not points (Score:3, Informative)
Also, while at any instant there are points that geometrically correspond to the Lagrange criteria, in practice a body near one of these points would follow a stable "halo" orbit near the point (with minor adjustments to maintain that orbit near the unstable L-1 and L-2 points). These stable halos can occupy a lot of space - 20-30% of the otherwise smallest dimensions involved (Moon-L1/L2 or Earth-L1/L2 distances for L1/L2).
Also note the old L5 society turned into the National Space Society [nss.org] some time ago.
L3 isn't useless... (Score:2, Informative)
Re:Democratic countries? (Score:2, Informative)
Thats like saying "My bike is not blue; it's pedal powered."
'A democracy' and 'a republic' are two orthogonal concepts. A republic may be democratic, or it might not be democratic. The USA is democratic republic.
Re:yes (Score:3, Informative)
PWI. Just say no, kids!
The Lagrange points are orbits, they just happen to be fixed in relation to the orbits of the other two bodies. L4 and L5 are also called "Trojan points" (Google is your friend). They are 60 degrees ahead and 60 degrees behind the Moon, in this case, and orbiting the earth at the same orbital radius and speed as the Moon. What effectively happens is, the gravitational pull of the Earth and the Moon are equal at that distance, so anything in orbit in either of those places never catches up to the Moon, nor does the Moon catch up to the other. If you were in orbit around the Earth at the same distance as the Moon, eventually either the Earth or the Moon's gravity would pull you out of the stable orbit towards one or the other, whichever was closer.
Well, anyway, go sober up, drink lots of water, and read this in the afternoon.
Interesting Quote That Seems Appropriate (Score:5, Informative)
Look at the Big Picture through the perceptive eyes of foreign policy analyst Chalmers Johnson, who notes in his book, Sorrows of Empire, that conquerors of all eras have built encampments and forts in subject provinces, but there is something unique about the Americans:
"What is most fascinating and curious about the developing American form of empire, however, is that, in its modern phase, it is solely an empire of bases, not of territories, and these bases now encircle the earth in a way that, despite centuries-old dreams of global domination, would previously have been inconceivable."
Aside from the interest groups that benefit economically from a policy of militarism and perpetual war, and such factors as securing oil and other resources, Johnson sees
"Something else at work, which I believe is the post-Cold War discovery of our immense power, rationalized by the self-glorifying conclusion that because we have it we deserve to have it. The only truly common elements in the totality of America's foreign bases are imperialism and militarism-an impulse on the part of our elites to dominate other peoples largely because we have the power to do so, followed by the strategic reasoning that, in order to defend these newly acquired outposts and control the regions they are in, we must expand the areas under our control with still more bases. To maintain its empire, the Pentagon must constantly invent new reasons for keeping in our hands as many bases as possible long after the wars and crises that led to their creation have evaporated."
So now these same assholes want to dominate the entire world from the LaGrange Points.
Re:Rivalries are good (Score:5, Informative)
The lagrange points are basically 60degrees in front of and behind the smaller object in it's orbit, between the two objets, just past the small one, and on the other side of the big object from the small one.
Check the first link in the blurb, it'll take you to the L5 societies homepage where you can get a MUCH better explanation along with pictures.
It's also possible to have more than one occupant at a lagrange point, as the 'point' is more like a area. While this point is a tiny space compared to the two bigger objects, it can be fairly large compared to a man made structure. Though the farther from the centre of the Lagrange point you are the more use of correctional thrusting you'll need.
Contrary to common conception lagrange points aren't like magical peg holes that you 'lock' to when you get there, what they really are are places where if you stop there the various forces from the two larger bodies will ballance out such that you won't need to do anything to stay there. but this is the ideal, with perfect spheres and NO other gravitational souces, no solar wind, etc. So you'll always need tiny corrections from time to time, the L points just reduce this to the smallest amount, so by being willing to deal with slightly more correction you can park very near there. Again the L5 society has better info most likely, and if not google for it, I'm sure some-one has expounded with more accuracy and eloquence than I have mustered.
Mycroft
Re:Yes (Score:2, Informative)
Most of the military forces in the US today are federally funded (there are actually exceptions [wikipedia.org]), but a good chunk of them fall under a dual command structure, and I'd say we're only some new state tax laws away from changing the "federally funded" bit if the need arises.
Also, part of having an Eighteenth Century constitution means having Eighteenth Century ideas about federalism and statehood. As such, the states are constitutionally allowed to go so far as to raise armies and prosecute a war on their own if they're "actually invaded, or in such imminent Danger as will not admit of delay."
There's also the issue of our soldiers and militiamen taking an oath to the constitution itself and not to the government. Sure, the oath will be taken more seriously by some more than others, but there will probably be a non-negligible number of them unwilling to carry out any orders they see as unconstitutional, and some of those might even jump the fence.
So just because you can't have a "classical" civil war in the US tomorrow, it'd require quite a bit of constitutional amendment (which would require the consent of the states) to keep one from being possible in, say, 50 years.
Re:Interesting Quote That Seems Appropriate (Score:3, Informative)
I'm not sure the number of US bases is the real issue, although the last figure I saw was in excess of 700 IIRC. I suspect the size and positioning are more significant.
The US is apparently relocating many of the South Korean bases south on the peninsula - evidently because they expect the conflict there to go hot at any time, and the existing bases will simply get 35,000 US troops killed in three hours. They also needed to move a lot of South Korean US troops to Iraq due to the manpower shortage.
There's no doubt that the US is projecting military power much further than they used to and for political and economic motives - the penetrations into Eastern Europe, Africa, and the Middle East make that crystal clear.
In any event, it's clear that the suggestion of using the LaGrange Points is more of the same, i.e. "We are the only power than can seize those points for military purposes, so we should do so regardless of whether it makes any sense militarily, financially or politically."