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[Max White]

3. Unlike CHaron(Pluto's moon), the moon isn't always foating above the same spot of earth. Therefore you space elevator's groundstation would need to fly all around the earth.

Charon is in geostationary orbit of Pluto?
Does it also do that thing outs does where it always faces with the same side? Not sure what to call that... Basically it's period of orbit is the same as it's period of rotation so they cancel each other out.

[10ebbor10]

3. Unlike CHaron(Pluto's moon), the moon isn't always foating above the same spot of earth. Therefore you space elevator's groundstation would need to fly all around the earth.

Charon is in geostationary orbit of Pluto?
Does it also do that thing outs does where it always faces with the same side? Not sure what to call that... Basically it's period of orbit is the same as it's period of rotation so they cancel each other out.

It is.
It don't know what it's called but the phenomena that causes it is called tidal locking. Also , Yes

[Max White]

So assuming we had a material of reliable structural integrity, could we build a bridge between Pluto and Charon?

[10ebbor10]

So assuming we had a material of reliable structural integrity, could we build a bridge between Pluto and Charon?

I don't think so , because Charon's orbit is elleptical.( Ie the gap isn't always the same size)
But if your design is sufficantly strong and elastical, I think it's possible. (just make sure it's properly heated, on a cold day Pluto's atmosphere freezes.)

[Max White]

Well I figured it would be elliptical, I mean do we have anything in perfect orbit around anything?
But you could still design a bridge, assuming it wasn't a rigid structure. Something like a piston that is expandable... Could use it as a giant fucking pump and power all of Pluto's small but cheerful colonies with it!

[sneakey pete]

Well I figured it would be elliptical, I mean do we have anything in perfect orbit around anything?

There's a couple of dozen GPS satellites in a low earth constellation and 100's of communication satellites in earth geostationary orbit that are. Or at least, engineering standard perfect.

[Montague]

Have you seen the movie ”moon”?

Yes, that movie is awesome.

[Starver]

I agree that there is something to be said about most of the following, snipped, post but...

Also, a permanantly settled moonbase would not be likely, even if nominally self-sufficient

As compared to a space-station?

it's not easy to live there

As compared to a space-station?

It would be incredibly dangerous all the time there

As compared to a space-station?

and the safety requirements and low gravity would make things miserable for the people there.

As compared to a space station?

people would need to be rotated out at great expense

(Ok, so this would be greater than a space station, but you're breaking up my flow of objections)

or otherwise everyone would develop space madness, or moonmadness in this case

And compare this to a space station?

Not to mention the acculmative effect of radiation exposure.

The biggest error here, given that with the moon you can dig down into the regolith/rock and pile any spare that you happen to have over the top of you for good measure.  At least over the areas designated as shelters for the more extreme events that aren't within the tolerances already mitigated by the standard protections/time-exposure levels.


Anyway,

We are just running out of money. We can't even get normal factories and towns on earth to prosper right now, how would a moonbase do any better?

To be honest, money is an ephemeral concept.  Our problems with money right now isn't because we're running out of chickens, or leather hides or bars of steel or even the little round discs of non-precious metal and other pulp/fabric/polymer-based tokens representing monetary values.  It's because the fairly arbitrary and almost entirely disconnected association between the concept of currency values and the physical needs and provision of services has been sent out of whack by people who "use money to make money", with that particular kind of money having been not even composed of said physical substances, but almost entirely conceptual.


Actually, we are running out of resources, insofar as consumptions are concerned (the "if everyone on the planet was American/whatever we'd need 4.5 Earths to keep them living as they already do" thing, or somesuch value that's got huge error bars on it anyway).  But I'm not expecting MoonFarms(TM) to be a solution to that.  (f/when we get into space on a self-sufficient basis, though, we should at least know how to be a lot better at keeping ourselves supported, though I suspect that most 1st-world 'Groundsiders' will continue to pig themselves out on the easier to import (from 2nd-, 3rd-, Off-world sources) foods and other stuff, rather than adopt the much more spartan spacer way-of-life (itself being positively decadent compared with the current starvation areas of the 3rd-world, and breadline families in the 1st still also comparatively suffering).


Physically, it is basically doable.  And, actually, financially so either by rejecting the current system (getting more 'realistic') or by actively embracing it in the expectation that the boom you artificially inflate will provide the required dividends well before the marker is called back in again. (Or having the "reject the system" solution at hand t bring into the end of it, but that's even more a bit of a dodgy one than the embracing solution!)

Not that I'm calling here, for an anti-capitalist (or hyper-capitalist) revolution, prior to space, but that would be one way.

The other way is to drip, drip, drip the space tech into our lives.  Millionaires on SpaceShipTwo tomorrow, the pretty well off sometime thereafter in a trickle-down effect; at the same time exploration discovers something we particularly want (or need to deal with pretty sharpish) and we send up a set of miners/rig-jockeys to have a go at it, which eventually expands into a trickle-up effect; all the while, the scientists that are currently doing their own 'thang' expand their activities in vanguard, support and follow-up research activities of various kinds (i.e. prepping expeditions, giving specific expertise to any that go out there and clear up the messes and develop improvements for the followup/continuation of the not-fatally-flawed attempts.  Except that I'm worried that this approach is going too slow.  But a few key techs (high-altitude launches from buoyant platforms, if not space elevators, and various improvements in space medicine) could be the answer.  Or it could be something unexpected.  And that's not even considering some kind of First Contact assistance; Ferengi/Centauri opportunist traders; some guys wandering over and telling us that we're the 13th colony or origin planet; portal/Stargate/'Door' technologies; worldwide 'ascendence' to non-corporeal forms, whatever...

But that sort of thought tends to go off-the-wall quite easily.  Perhaps best not to let the latter part of that diatribe be a point of discussion.

[Starver]

Venus is where we want to go. We can terraform that puppy in 20 years. Use the science from that to combat any sort of climate change on earth. Also have a near earth planet in weight.

Optimistic, but I like your thinking.  Most people (and I actively avoided mentioning it) gravitate to Mars, and terraforming that (in far more than 20 years, unless you're called Arnie and happen to put your hunking great fist in it, but most of the work was done for him, already).  And, yes, I've read KSR's RGBMars trilogy.  It's not far off feeling plausible, when you do some very loose maths and conceptual thinking.  But I also like the Mercury base that's described, even though I think that's off the end of the scale!

[Starver]

Except your talking about digging stuff up on the moon. I really don't see why you think that making occasional adjustments to dodge things in LEO is harder than... flying all the way to the moon. landing on it, and then digging a hole.

(You're.  Sorry.)

Luna 16, 20, 24 did this automatically, albeit in small amounts.
Apollo missions did this with people, albeit in only slightly larger small amounts.
The aims of none of these were to actually dig holes, but as a proof of concept they work.

And these all got the stuff back to Earth (and, in the case of Apollo, the people, which is probably a more relevant achievement unless you're considering fully-automated, one-way or indeterminate-return missions).

Add 40+ years of robotics and general mechanical tech innovation, I don't see any big reason why holes can't be dug (even into the sub-regolith rock) big enough to at least shelter in for the more extreme solar events, while piling up spare regolith over the 'surface' capsule.  Details need to be worked out, but it's not... ahem... rocket science.

If in doubt, get multiple automated construction vehicles down to the chosen spot, get the job started, account for such breakdowns as are likely to occur during such an unattended phase and then when you're happy you can send (at the very least) an Apollo-style manned mission to land there.  And if they're not going to land within walking distance (probably wise not to land exactly on target, if it's being built up and dug down, but actually I don't see why a dedicated landing pad/beacon couldn't be part of the original building spec in order that they do so) then mission abort, try again later, much financial hand-wringing, but given the investment you'll already have other flights planned anyway, if not a backup Moon-orbit-to-surface opportunity that you can immediately try.

Big problems (total descent stage failure, unforeseen base structure/integrity malfunction, aliens) may happen.  I still think that's part of the risk.  It was with Apollo.  Have you read the 'backup speech' that the President would have said had Apollo 11 not got down safely/never been able to return?

The big problem with the US space program these days[1] is that it's not competing with Russia.  But coming up in the off-side lane (and some are actually doing quite well, given their late start) there are other competitors.  I'd actually like it if it were cooperative, but there's got to be some competitive spirit to be eked out of this situation, and this is the only way that some people are going to do in the short-term what is pretty much required to achieve the mid-term goals and absolutely essential for the long-term to end up where I think it should end up.  (YMMV.)


Oh, and I happen to like olivine.  I don't see so much of it these days, though.


[1] I speak as a Brit, where our space programme effectively terminated upon the success of Prospero (first and only British satellite launched by British rocket), and only resumed in various alliance programmes.  Except for our secret base on Titan I don't think we really fulfilled any of the expectations.  Dan Dare, where are you?

[Starver]

I would rather not like to use Ion/nuclear drives that close to earth(Isn't very healthy) and you wouldn't gain that much time because halfway there you already need to slow down.
Chemical drives might be useful because they use way less fuel, but also provide less thrust.

Vice-versa, I think you mean, Shirley?  Ion drives (whether nuclear-powered or not) are currently small-but-constant thrust devices.  You keep the drive on for roughly half the trip (in a non-freefall but effectively still microgravitational situation for equipment/cargo/passengers on board, something around 1/1000th standard g, last I heard, but depends on engine/structure+payload mass ratios) then swivel round and keep the drive on for the deceleration phase.  Smart 1, IIRC, took a little over 6 months to get to the moon, using this method.

Chemical rockets give a large boost (not as fast a propellent ejection, but more of it, and thus also used up quicker) over a short amount of time, then coast for approx 3 days, then boost to decelerate into Lunar orbit (again, IIRC, ICVWBW, but that sort of time).

(I am assuming that your "more/less thrust" was meant as "more/less acceleration", as of course total specific impulse and/or total delta-V is another measure and accumulates over time to give the advantage back to the ion thruster.)


Currently, ion-drives are only really useful for unmanned probes.  It gives them various alternatives when it comes to inter-orbit travel (given that the thrust can be kept on for longer), with various alternative and effectively unlimited energy sources (nuclear, solar) to empower the super-speeding of the minute amounts of irreplaceable propulsion mass.

I think there was a European satellite mission with an experimental ion-thruster on it (as it happens) that failed to reach GS orbit, or wherever it was actually supposed to go, with the final chemical-stage failure, and could only achieve LEO, and the experimental thruster was actually used to transfer it the rest of the way!  It was only supposed to do experiments and/or station-keeping duty, but sounds like it worked quite well, if I'm not misremembering it.

[Starver]

3. Unlike CHaron(Pluto's moon), the moon isn't always foating above the same spot of earth. Therefore you space elevator's groundstation would need to fly all around the earth.

Charon is in geostationary orbit of Pluto?
Does it also do that thing outs does where it always faces with the same side? Not sure what to call that... Basically it's period of orbit is the same as it's period of rotation so they cancel each other out.

To add (as I already have been doing, copiously[1], sorry for the string of posts, but the alternative is one long TL;DR;) whereas the moon's rotation is locked so that the Earth is selenosynchronous (not quite selenostationary, as noted[2], and there's a visible wobble of the Earth across its skies as it we relatively travel in further/nearer parts of the orbit around our barycentre), the Earth is rotating differently and is not (yet!) locked to the moon.

But Pluto/Charon have become mutually locked (as we may well be, eventually) so have equal <Foo>synchronous orbits.  Charon in plutosynchronous orbit, Pluto in charosynchronous orbit.


They are also so alike in mass (Pluto approx 2/3rds of Luna mass, Charon approx 1/3rd of Luna mass, which makes their combined weight interestingly close to the moon but for no apparent reason other than synchronicity) that the barycentre is actually between the two masses, not within the major body (as in Earth/Moon or almost every other significant relationship in the solar system) so that makes me think that you'd have a handy (unstable!) Lagrange point from which to send your tethers down to each rock from.

Maybe (would take more facts than I have at hand, and a barrow-load of calculations that I'm not confident I can do for myself) make it like those fancy retractable modem-cables (that pull out from both sides, the middle held on a wheel that is sprung so that when not ratchet-held they both recede at equal rates again) and you could have your permanent connection between the two bodies, the slack being taken up, as required within the station itself, now being held taught at (roughly!) L1, even on the unstably equilibrial axis.

If the tolerance doesn't cater for the fluctuating position of the station mass, however, and thus to succeed it needs the cable to retract/expend at (maybe, would seem logical) twice the rate for one body than the other, I'm sure some entirely mechanical gewgaw could be part of the internal tether-holding structure to ensure this was done automatically, however.

It'd be difficult to accomplish, but once you're in the position to actually go to Pluto, goshdarnit, and have enough interest in the bodies to actually want to do such a thing, if we aren't able to work out such a relatively trivial engineering principle then the people who should be doing so have obviously been sitting on our hands for too long and need to be sent there to examine the situation, first hand...




[1] Oh, and by the way, I forgot to say in the last post that ion-drives would be useless in atmospheres of any density, so even if you had radioactively-inclined ion drives, you probably wouldn't be seeing significant amounts of radiation exhausted to concern us below LEO.  There are already nuclear materials taken into space (and precautions supposed to be made in making sure those that ever re-enter are safely encapsulated) for nucleothermic power purposes, but the reactant mass of an ion drive is likely to be stable under most schemes being considered, anyway, even if the power comes from said device.

[2] Although I do often use the latter variant term when I mean the former.  Even while I maintain something like the correct root.  (geo-/area-/whatever)

[mainiac]

The moon's crust is 99% feldspar, olivine and other volcanic rock. Everyone here should know that olivine isn't worth anything and there is literally no shortage of it here on earth. There is nothing worth mining there. Also, if you know anything about mining you know the profit margins are razor-thin. A moonfoundry's accounting moonoffice would quickly run out of red ink to printing their quarterly reports.

1)  You don't mine by picking a completely normal place and start digging.  You mine by picking a place where you are actually likely to find something.  In addition to there being many parts of the moon where simple surface mining would be high yield, you can go to places of asteroid impact or past volcanic activity and be pretty much assured of a jackpot.  Just the most rudimentary surface mining would put a huge amount of minerals in play.

2)  Moon dust itself is pretty valuable stuff.  A lot of it is either silicon dioxide or various types of simple bonded metal oxides.  Pick a place where the surface has what you want and you don't even need to dig deep.

3) The value of lunar materials isn't their composition, it's in their location.  We pay $5,000 a pound to put stuff into low earth orbit.  Anything built on the moon could be put into lunar orbit for next to nothing with a simple kinetic launcher and would be relatively cheap to take out of lunar orbit from there.

[Eagleon]

1)  You don't mine by picking a completely normal place and start digging.  You mine by picking a place where you are actually likely to find something.  In addition to there being many parts of the moon where simple surface mining would be high yield, you can go to places of asteroid impact or past volcanic activity and be pretty much assured of a jackpot.  Just the most rudimentary surface mining would put a huge amount of minerals in play.

Isn't the moon pretty much mad with iridium, compared to the Earth? Also yeah, those asteroids have to go somewhere. If the crust really is so compacted by meteorite impacts that it's actually difficult to dig through everywhere, it has to be possible to find some sort of shiny, in particular on the far side where craters are much more numerous and fresh. The extent of our surveying, as far as I recall, is the apollo missions, orbital spectroscopy (which is inevitably inaccurate due to lunar dust), and a few impact and lander probes. On a sphere with the surface area of Africa, can you really say that we know what's available?

Not even mentioning the enormous boon to nanomaterials, metallurgical, and other such research. Certain materials and components have already been established as much easier to make in low gravity. Engineers are pretty much guaranteed to come up with more.

[palsch]

palsch, permission to repost that in other locations, with attribution and link?

Sure. Could you link to anywhere you post it though?