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Conquering the LaGrange Points?
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?"
You will hate me for this comment but just so you know there is no such thing as a centrifugal force. There is centripetal force, but no centrifugal.
I don't think the french have a monopoly on bureaucracy. Take a look at the paperwork requirements to make a commercial space flight from the US and then consider that you as a US citizen are prohibited from launching from another country to dodge said paperwork requirement.
Haha, the great thing about space is that there aren't any choke points.
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.
Javascript + Nintendo DSi = DSiCade
LaGrange points are the points in relation to two bodies, in this case the Earth and Sun, such that a body of neglegible mass will maintain its distance from the first two bodies. That is, relative to the Earth and Sun these stations wouldn't move. These points are here.
Strictly speaking, a LP does not occupy any space at all, that's why its called a 'point' in the first place.
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.
There is no such thing as centrifugal source. There is, however, centripetal force.
I don't know where this CamelCase spelling comes from, but I bet poor ol' Lagrange would be surprised.
Gravitation is a theory, not a fact.
Haven't followed the space colonization subject very closely for the last 20 years or so, but the subject was discussed in detail as early as the late 1960's.
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.
Two words: Orbital mechanics.
g range.html
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
-- Dan Jenkins, Rastech Inc.
This entire question is ridiculous. Although L4 and L5 are points in space, there is a HUGE area of space both circumferance wise and on either side of the actual points to occupy. We're not talking ten square feet here. I imagine every craft and station ever built could easily fit nicely. Perhaps even that number times a thousand. Space is big.
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)
I'd be much happier if we conquered the Lagrange points first.
It's not capitalized oddly. It's just spelled Lagrange. As in, Joseph Louis Lagrange.
L1 and L2 are unstable on the timescale of 23 days.
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.
or so ZZ Top says:
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
Actually, the Lagrange points are terribly huge chokepoints - the (apparently) lowest-energy transfers (the Interplanetary Superhighway) all pass through Lagrange points.
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.)
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
-- Should you believe authority without question?
The Solar and Heliospheric Observatory is currently in orbit at L1.
L2 is occupied by the Wilkinson Microwave Anisotropy Probe, and in the future, a telescope is planned to occupy that location.
The derivations are linked on a page off of Wikipedia.
a grange.html) for L3's timescale.
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
Yeah, the dictator has been replaced by DU debris too...
If I point out that you are incorrect, making me a foe does not make you any more correct.
"The British Parliament offered seats to the Colonies" Sure they offered a seat or two, but not enough to make a fucking difference.
Actually, you can put a spacecraft at any of the L points and get it to stay there... it may just require a small amount of propellant. For instance, while the L1, L2 and L3 point are all unstable to varying degrees, there are periodic and quasi-periodic (Lissajous) orbits that exist around each of these unstable points. The radii of these halo-like orbits are quite small (at least compared with the distance between the two massive bodies) so they may as well be stationary at the respective L-point (from a mission utility point of view).
"It takes considerable knowledge just to realize the extent of your own ignorance." - Thomas Sowell
In addition to the Earth-Moon Lagrange points (in geometric relation to the Moon's orbit), there are similar Earth-Sun Lagrange points. The Earth-Sun L-4 and L-5 points are pretty far away of course - 60 degrees ahead of and behind Earth's orbit around the sun. So probably not terribly useful. But Earth-Sun L1 and L2 are definitely useful - only a couple of million miles away.
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 some time ago.
Energy: time to change the picture.
...you just need a relay at L4 or L5. Not sure about the early human habitation prospects, but once L4 or L5 are occupied, it seems that it would make a pretty good place for unmanned sattelites.
Fill in your four or five-letter word of wisdom here _ _ _ _ _.
Don't forget that the USA is not a democracy - it is a Republic.
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.
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.
By the taping of my glasses, something geeky this way passes
I just read Justin Raimondo's latest column over at www.antiwar.com and he quotes foreign policy analyst Chalmers Johnson as follows:
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.
Richard Steven Hack - This sig is TOO GODDAMN SHORT TO DO ANYTHING USEFUL WITH! MORONS!
Actually there are 5 lagrange points(as the blurb says). And I think we're talking about the earth-moon lagrange points here not earth-sun.
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
https://signup.leagueoflegends.com/?ref=4c3ed6600b6ea
" The USA and most countries only have one federally-owned/funded/operated army."
Most of the military forces in the US today are federally funded (there are actually exceptions), 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.