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NASA Discovers 'Motorway' Network Between Planets
Ananova ^
| 7-18-2002
Posted on 07/18/2002 4:13:04 PM PDT by blam
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To: VadeRetro
Read on. You're right about three, wrong about two. Yeah, I saw.....
So, I claim I was 60% right. (THat's what I get for going for a conclusion without ever having looked at the calculation.)
But I'll amend my comment in this way: I would think that the two stable Lagrange points are small islands of dynamic stability embedded in a larger island of dynamic instability. So, I still doubt there will be much space flotsam there....
To: PatrickHenry
How much fuel does it take to travel in an orbit? I assume this is yet another example of idiotic journalism. Once you get to one of the two dynamically stable Lagrange points, it shouldn't take any fuel to stay there, but at the other three, which are dynamically unstable, it would require occasional small maneuvering thruster burns to null out the effects of pertubations, which would otherwise cause the spacecraft to drift out of the unstable equilibrium.
At least I think that's the case....
To: PatrickHenry
How much fuel does it take to travel in an orbit?It depends upon where the orbit is. Orbiting anywhere other than a Lagrange point is unstable and the orbit will decay without using fuel to stay in place. Think about all the space stations that have crashed.
103
posted on
07/18/2002 8:21:40 PM PDT
by
altair
To: longshadow
So, I still doubt there will be much space flotsam there.... I don't know. I'm an ex-JPLer but a programmer not a rocket scientist. I recall reading a science fiction story that used that idea as a plot twist. The space ship in the story was accidentally sent through a Lagrange point and the ship suddenly started getting pummeled with junk until they changed course to avoid it. The moral being what you don't know can kill you.
My guess is that there would be garbage there, the same as Jupiter captured asteroids as moons, but I'm neither a rocket scientist nor a mathematician.
104
posted on
07/18/2002 8:30:35 PM PDT
by
altair
To: altair; RadioAstronomer
My guess is that there would be garbage there, the same as Jupiter captured asteroids as moons, but I'm neither a rocket scientist nor a mathematician. And I haven't seen the calculations, so I'm just going with a gut impression; I trust others who know for sure will be able to fill us in....
To: Just another Joe
42! wasnt that the answer to life, the universe, and everything? It has been working for me so far.
To: altair; All
To: petuniasevan
I'll buy what you related to me
Low gravity zones between planets -- but honestly don't these things cahnge minute to minute the planets are rotating what you may save in fuel economy you would loose as you had to keep place with your low gravity portal and the faster the planet moves the more impractical this sounds. Say for example we want to chart a flight to mercury it travels around the sun in 88 days I think how many rorations would it achieve before you arrived? 10 - 15 trying to stay in it's gravity well would not be possible at this time.
What then about Mars 2 years of flight I'm told to get there using the straightest route and compensating for orbit -- how would you in a two year flight in this highway?
In theory it may sound reasonable but the application is nott very practical sounding
I'll have to give this some more thought.
To: VadeRetro; altair
AH, I now can claim partial vindication:
from:
http://www.wikipedia.com/wiki/Lagrangian+Point
we find:
"In practice the stability of Lagrange points is not real, as there are more than three bodies in the universe. Additional gravitational pulls from elsewhere cause objects to move away from the point. The first three Langrangian points are stable only in the plane perpendicular to the line between the two bodies. This can be seen most easily by considering the L1 point. A test mass displaced perpendicularly from the central line would feel a force pulling it back towards the equilibrium point. This is because the lateral components of the two masses' gravity would add to produce this force, whereas the components along the axis between them would balance out. On the other hand, if an object located at the L1 point drifted closer to one of the masses, the gravitational attraction it felt from that mass would be greater, and it would be pulled closer. (The pattern is very similar to that of tidal forces.)"
"However, in the particular case of the L4 and L5 points, Coriolis forces begin to act on an object moving away from the point, and bend the object's path into a stable, [kidney bean]?-shaped (from the viewpoint of the smaller mass) orbit around the point. This arrangement is stable. In the Jupiter-Sun system several thousand asteroids, collectively referred to as Trojan asteroids, are in such orbits. Other bodies can be found in the Sun-Saturn, Sun-Mars, Jupiter-Jupiter Satellite, and Saturn-Saturn Satellite systems. There are no known large bodies in the Sun-Earth system's Trojan points, but clouds of dust surrounding the L4 and L5 points were discovered in the 1950s. Clouds of dust, fainter than the notouriously difficult gegenschein,
are also present in the L4 and L5 of the Earth-Luna system."
So, in summary, even the L4 and L5 points can't be truly stable, because there are more than three bodies exerting force. Lastly, an object at L4 or L5 subjected to a pertubation assumes a "orbit" around the Lagrange point that is stable, but it is NOT forced back into the original equilibrium location.
To: PatrickHenry
How much fuel does it take to travel in an orbit? The Algoresat, sitting in a warehouse and ready to fly on his inauguration day carries enough onboard fuel to stationkeep at L1 or is it L2 for several years. If they can stay inside a small radius, all that is needed is a puff of gas now and then. There are already a couple of satellites there, though, and I wonder if they can safely avoid each other or if it matters since they would hardly be moving relatively anyway. L4 and L5 wouldn't need any fuel at all, they will orbit forever.
To: longshadow
Clouds of dust, fainter than the notouriously difficult gegenschein, are also present in the L4 and L5 of the Earth-Luna system."I claim vindication as well -- there is garbage there. Thanks for the info.
111
posted on
07/18/2002 10:31:13 PM PDT
by
altair
To: snopercod
Lots of stuff. In my post I was referring to something from a book called The Mote In God's Eye. This is a great book which I highly recommend.
112
posted on
07/19/2002 7:32:59 AM PDT
by
CaptRon
To: CaptRon
Powder..Patch..Ball Fire
The Mote in God's Eye... See there are a few of us...
To: longshadow
I'm vindicated too because if everyone else is I'm not going to be the only one that isn't.
To: VadeRetro
I'm vindicated too because if everyone else is I'm not going to be the only one that isn't. Why not! Plenty to go around!
To: VadeRetro; longshadow
Hey, I'm vindicated too - I was right all along about...whatever it is. And you can't prove otherwise. Mainly since this is my first post on the subject, but that's all over now...
So I was right all along. You guys just didn't know it..
To: general_re; VadeRetro; longshadow
I don't know what you guys are talking about, but I suspect you're all wrong.
To: VadeRetro
SOHO is in one of the earth-sun points. Did you see the SOHO pictures of the solar flare?
To: <1/1,000,000th%
Did you see the SOHO pictures of the solar flare? No, and it was a really crappy night for trying to see auroras where I live. Oh, well! I did manage to see a little red flickering in the north some months ago when another big one went earthward.
To: general_re
Mainly since this is my first post on the subject, but that's all over now... So I was right all along. You guys just didn't know it..
Ah; one of those "vacuously true" scams...... pretty sneaky of you. You probably are hiding something behind the 1st Amendment, or the 2nd Law of Thermo, or something like that.
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