Above piccie shows the locations. L4 or 5 would be better choices as objects there remain in place where the others need to expend fuel to maintain position.
NASA is looking at the possibility of parking a manned outpost beside the Moon as a way station for astronauts on their way to deep space missions. Star Trek Deep Space Nine The way station probably won't look anything like this. According to a memo from William Gerstenmaier, NASA's associate administrator for human …
> Above piccie shows the locations. L4 or 5 would be better choices as objects there remain in
> place where the others need to expend fuel to maintain position.
Actually the blue and red arrowheads show the tendency at the various points. Objects at any of the points will require some minor orbital adjustments from time to time. On a potential surface L1, L2 and L3 are saddles and a body there will have the tendency to run away in one of two directions; L4 and L5 are hilltops and the tendency there is to run away in any direction. The advantage to any of the Lagrangian points is that in their vicinity the potential curve is relatively flat and orbital adjustments required would be minor.
My understanding is that Lagrange points assume a 2-body system. When your satellite is much, much lower mass than the 2 bodies you are talking about that's OK, but then when you add in the sun, and the other planets, it's not so simple.
The example you give of the Jupiter system is quite extreme, because of the mass of Jupiter compared to the inner planets, but when you look at the Earth-Moon system, the sun and inner planets have a lot more influence.
From what I've learned of orbital mechanics, none of the Lagrange "points" around Earth are actually stable, however you can have some interesting orbits around the Lagrange points that don't require much station-keeping.
You would think that, but you actually get stable orbits around L4 and L5. Try to think of them as points with negative mass and thus negative gravity, and like you will form an orbit around a well, and not fall in it, you will thus make an orbit around a hill. It makes my head spin every time, but greater minds than mine say they are stable and that you do get an orbit in them and the orbit comes naturally. Besides we actually observed them to be stable as well, so it isn't even theory, it is observed facts.
The thing is, that they aren't intending to put it in the exact point behind the moon. It would orbit in a circular motion in a plane that is perpendicular to Earths orbit. That means that it would appear from the Earth to be travelling in a circle around the moon. I would guess that the NASA DSN would be used to talk to it.
They are semi-stable. L1, L2 and L3 are saddle points. So you if are a little bit off in the plane that is perpendicular to the line between the heavier objects in your system (in this case the Earth and the Moon) you will be drawn towards the point and be pushed out along the line. Now then, since you are drawn to a point in a plane you naturally create an orbit in that plane. The problem is of course that have to stay in that plane, if you stray just a little you will fall off, however it is fairly "easy" to maintain and consume less fuel than to balance the craft in the point itself.
If I recall this correctly the SOHO orbits L1, but that might also be due to being able to keep the the radio link open. The sun is after all directly behind L1 (earth-sun).
As for keeping tabs on our friends behind the moon a relay satellite in any orbit around the moon can do that for you. And if you want a constant feed you just need to have the orbit being on the plane perpendicular to the earth-moon line. When you are that far out in both directions a few kilometers off the surface is probably sufficient to being able to see both points.
> The thing is, that they aren't intending to put it in the exact point behind the moon. It would orbit in
> a circular motion in a plane that is perpendicular to Earths orbit. That means that it would appear
> from the Earth to be travelling in a circle around the moon. I would guess that the NASA DSN
> would be used to talk to it.
The thing is that while it would orbit in a circular motion around the moon, the moon is orbiting in a circular motion around the earth. From the earth it would appear to be orbiting the earth at the Lagrangian point L2. Which is directly behind the moon. All the time. And from the moon, whose face is turned towards the earth all the time, the backside of the moon faces L2. All the time.
I don't follow the bit about L2 orbit being perpendicular to earth orbit.
I guess it may become crowded at these points in the future, any stations there will still need fuel taking to them so they can control their proximity to others. At least there won't be a problem with space junk whizzing about, it'll just stay there or gradually go into orbit around the Earth, Moon or Sun.
The US at some point is going to have to pay back all that cash it borrowed. $15 Trillion ( Nov 2011 ) and growing, Austerity may not have hit Uncle Sam yet, but it will and a NASA/US funded moon orbited station is never going to happen. Europe cannot afford it as we ( Collectively ) owe around $10 Trillion ( Feb 2012 ) and growing.. China isn't going to want to spend the cash just yet as its dependent on Europe and the US buying their stuff. But @Sureo is correct, the only country that could eventually financially consider this is China.
We should all maybe start learning Mandarin if we want to go into space.....
"The US at some point is going to have to pay back all that cash it borrowed. $15 Trillion"
No it won't, merkin-land will just invade/bomb/threaten some oil producing country and then “The markets” will speculate on the price of oil thereby driving up the price and all those dollars will disappear as petro-dollars, never to return to merkin-land and dilute the value of the non-petro-dollars.
FWIW, the management of American debt is ENTIRELY DIFFERENT than KILLING OFF ALL DEBT. Having said that, I agree with those that feel that the American Economy is not large enough to sustain $15,000,000,000,000 and its interest payments in an ongoing basis. Fortunately, much of the TARP funds are being retired and they make up a significant part of that number. As soon as the economy is out of the tank, we need a balanced budget, too!
Why would one would prefer L2 over L1 or L3? All three require an ongoing supply of fuel and L1 and L3 have direct access to Earth. I agree with the others that noted that L4 & L5 have much less of a fuel requirement (theoretically, it could be zero).
We ARE only talking about a NASA exploratory group. It looks like the NASA planetary (robotic) budget is getting trimmed from $1.5BN to $1.2BN, so that could mean $300Mn are being freed up for manned-exploration. We have to keep an eye on this.
My thoughts exactly. From a deep-space research point of view, go ahead. I'm sure they will learn all sorts of interesting things. But as a "Space station" or stopping off point for deep-space travel it seems a logistical burden. Once there, NASA would feel obliged to use it in order to justify the expense but getting parts, fuel etc out there is going to cost serious fuel without any obvious gains.
Apollo 17's Harrison Schmidt proposed an Apollo mission to the lunar far side with a landing site in the crater Tsiolkovskiy. It would have used a TIROS satellite orbiting around L2 to talk back to Earth.
It never went much beyond a 'what if?' and the budget cuts to Apollo doomed it.
we wil do a study which will cost umpteen million dollars to then say it wil cost 1 mega jillion dollars to do. to get the project working the most important thing is to test how the micro gravity will affect ants screwing in screws etc etc.
its a shame but i see space-x as our only hope to get off this rock which is unfortuante given the great minds at NASA.ESA,JAXA etc
NASA should seriously consider bolting an ion propulsion unit to ISS. It's not really doing anyone much good in low earth orbit, and it's already man rated, proved usable for long durations, plenty of solar power (for the ion propulsion unit). Just boost this guy to lunar orbit, or one of the libation points.
That way, built, usable hardware can do something, rather than just having NASA decide that it should just be burned up in the atmosphere, as they are want to do with "old" stuff.
If NASA was running the country, they would burn down cities that used "old" hardware, instead of doing upgrade-in-place.
It was thinking like NASA that got the USA the Superconducting Supercollider. Oh, wait... They don't have that, do they? They have the Tevatron.. uh, except that's been shut down, 'cause it's "old" and CERN is doing the particle physics research these days.
Take a hint, will you?
Why not exchange Dollars into Cubits and build a semi-Battlestar Galactica, except endow it with asteroid/rock/comet blasters instead of Cylon blasters, and park it in one of the appropriate L intersections?
The landing bays could be manufacturing landing ports to bring in raw materials and construct modules there.. Part of the vessel itself could be detachable or maybe part of it can be attachable so that other craft could mated to bring other types of ores.
Instead of "The Colonies" being aboard, it would be various nations with laborers and scientists aboard. If feasible, the vessel could move into and out of its "parking spot" if it has the thruster capacity.
Now, combine Galactica and Space:2099... Even some Star Trek Worker Bee pods. Don't see any need for a Jupiter 2 or Ming rocket ship there.
But, no need to build an entirely huge Galactica all at once. It could be constructed in modules, maybe at first far away near the asteroids, but built up, and provided thrusters so that it can be redirected as necessary, or just brought back toward Earth. Wouldn't it be cheaper to try to process and construct it where the raw materials are already out in space? I don't know about the catalysts and chemicals, though.
Anyone care to speculate on the minimum amount of raw materials and chemicals we need to bring up from Earth to achieve a critical mass of production out in space?
"The ISS is simply NOT SHIELDED enough for its circuitry and human residents to survive more than a few hours outside the Van Allen belts..."
Not to mention that the structure of ISS isn't designed to handle the dynamic stress loads of sudden and sustained high acceleration of the type needed to propel it to a cislunar libration point, or a trans-Mars trajectory insertion. If you rummage around YouTube a bit, you can find some impressive footage shot from a stationary camera bolted to a bracket in one of the main modules of ISS during an orbital reboost using the engine of a docked Progress. Pretty wild shit; I was amazed at all the shakin'n'quakin' that goes on inside that ship when they light the Progress engine for a reboost. Now, imagine the loads put on things like joints/seals between modules, solar panel hinges and trusses if you tried to strap a set of engines to that thing strong enough to boost it to an Earth/Moon libration point
Possibly one of the stupidest ideas NASA's ever floated, except of course that lets them sling another few million at the United Launch Alliance for a feasibility study rather than give it to private industry to actually develop technology.
High enough to need deep space level radiation shielding.
In a circular orbit so the Delta V requirement to actually get to it immense
In the unstable L-2 location so it's going to need lots of fuel runs
I'll bet you at some point they say its going to be manned so they can justify another expensive boondoggle like the Space shuttle.
I am an American Taxpayer, so I favor anything that furthers a reduction in cost for key objectives. SpaceX HAS been a good force for getting NASA past 'not invented here' scenarios. SpaceX has lofty objectives, so it is nice to think about them as championing new approaches to space tech.
I also agree that the whole Space Shuttle rigamarole has left people with a bad taste in their mouth for those suppliers. It would seem that staying at the Space Shuttle technology level has hurt the progressiveness of NASA.
OTOH, the progress for NASA in the interplanetary (robotic) probe area has been exquisite. Some of these same suppliers have performed MUCH better in this context. JPL's job of getting these probes to exotic positions has been unbelievably good. NASA and its suppliers have NO competition with success numbers like theirs.
@BB: Communicating with non-disadvantaged terminals at the distance of the Moon is more or less within the range of dedicated hobbiests. The DSN could probably detect the Moon station's receivers' local oscillators (if unshielded). A medium size dish (10 to 20m diameter? <- WAG) is probably plenty, even for fairly high data rates. The Moon station could use a little 1m dish. Monsterous DSN systems are not required.
We need some sort of staging point in high orbit where we can start producing fuel and other items from asteroid sources. It needs to be a balance of high enough orbit to be easy to reach from NEOs, and close enough to Earth for remote control and sending some human crew.
Instead of sending everything from Earth, send machines tools, and go grab a metal-bearing asteroid. Then you can bootstrap your production and cut the total cost by quite a bit.
I'm thinking the same thing, but some negativity-wielding spambot must be assailing us and others on this topic. It was kinda disappointing to see my comment slammed with two thumbs down when i thought I was promoting a better humanity, allowing for a nod to sci-fi that NASA and world governments could jump on, and helping put humans at work at new heights. But, spam bots (organic or digital) have no sentimentality, compassion, or impartiality....
While it's uncontestable that construction of such a station isn't going to happen unless Uncle Sam wins big from some Ursa Minor Beta Publisher's Clearing House Sweepstakes, the R&D needed to flesh out the idea is both affordable and worthwhile. It can thus be a truly international effort - NASA/ESA boffins doing the research, Chinese cyberwarriors stealing it, then their masters paying for it to be built.
Hahaha ahh hahaha! Oh, that was a good one. Hell, NASA can't even build a decent flying saucer, much less a space station. Yeah, I know, just keep the money coming. Well, all I can say is they better get off their lazy butts and do some work like the rest of us. Please, please, don't jump up and down showing me pictures of the Mars rover etc. We can't get there! Alright? You have pissed off more money than most third world countries. So, Shaddaaap, and build me a flying saucer. That or close NASA down and have Virgin Galactic build us what we need. They seem more capable at this point.
Indeed - I hear that it's lonely out in space, and in fact it's cold as Hell.[*]
* Colder, actually, going by the best account we currently have of Hell, which identified no region colder than not far below the freezing point of water (at presumably something close to sea-level atmospheric pressure). On the other hand, the thermal conductivity of ice-water is considerable, whereas in space you really only need to worry about radiative heat loss, and of course the heat of any mass you toss overboard for propulsion / alien removal.
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