Hells to the yeah!

[AJ Dual]

Wait, I thought our sun was lithium-deficient, due to having planets...

http://www.universetoday.com/44764/shedding-light-on-the-suns-lithium-mystery/

Hmmm...

You're right about that. So now I don't know why they would have said so on the astronomy program I'm watching.

However, there's also a lot of studies that say due to solar (stellar) convection and the fusability of Lithium, it could just be a function of the star's age, and some of the abstracts about stellar lithium and age  directly criticize the astronomy studies that imply lithium=planets because either planets suck up the lithium during formation from the protostellar disk, or that they actually help stir the star with tidal disruptions, because those studies weren't accounting for stellar age which would have fused the Lithium up.

Now I'm confused. 

Maybe it was astronomers talking out their ass on an area not their expertise?

[Fly320s]

Wait, I thought our sun was lithium-deficient, due to having planets...

So, the sun is depressed? Or manic?

[kgbsquirrel]

De-orbiting *snip*

Use a Saturn V in the skylab configuration, except instead of the skylab model, just a model filled with stacks of carbon tile heat shields (same tiles as the shuttle), cargo frames and parachutes. When you get a cargo you need to drop back down, just assemble the frame on one of the shields, strap in the cargo, and deorbit it. Do it right and the stacks of heat shields and cargo frames will be re-usable.

But without any gravity, I'm not sure how or if stuff would separate out 

Centrifuge? Speaking of which, I think we are entirely overdue in finally getting a centrifuge habitat installed on the ISS.

[kgbsquirrel]

I think it's possible, even likely there'll be lasers that can zap asteroid surfaces for spectrographic readings at a distance, however the energy needed in a laser to bore and make cuts deep into rock will be energy prohibitive, and cost prohibitive on the engineering side. Even the best stuff we've got now with the US Military like the megawatt and kilowatt "portable" lasers could probably only bore an inch or two into rock. There's constant improvement, but I don't see the engineering/economics of it increasing that exponentially that mining with lasers other than as sensor systems for spectography and perhaps LIDAR ever happening.

Asteroid mining will probably involve nets, lots of cables, maybe electromagnetic/static manipulation of dust, chunks thrown around by mass drivers maybe both as transport of materials and as reaction mass to move rocks into better orbits. Although perhaps dealing with the tangle of cables and nets might be difficult for robotics, so it could well be an indication that a human presence/touch is needed for some critical phases, unless someone's got a good scheme to just obliterate the entire asteroid and collect the rubble for processing.  

One of the other guys I think nailed this issue. Solar furnace. Very large mirror arrays to concentrate the solar energy down to a focused point, and then all you need to do is keep feeding the material into that point and in a manner to cause it to separate. Such as using a centrifuge that I mentioned earlier.

Here's a relatively miniscule (when working on the stellar scale) mirror array here on earth: http://youtu.be/8tt7RG3UR4c

ETA:
Holy shnikeys... bit of youtube surfing and I found another example of a solar furnace. Except this one can reach 3,500°C! @_@   For reference, Tungsten melts at 3422°C.  http://youtu.be/z0_nuvPKIi8

[HankB]

. . . Centrifuge? Speaking of which, I think we are entirely overdue in finally getting a centrifuge habitat installed on the ISS.

We might have had one under construction like the movie 2001 predicted, except after the moon landings we curtailed our space program funding in order to flush the money down the toilet of food stamps, welfare, and numerous other giveaway programs. 

[AJ Dual]

Use a Saturn V in the skylab configuration, except instead of the skylab model, just a model filled with stacks of carbon tile heat shields (same tiles as the shuttle), cargo frames and parachutes. When you get a cargo you need to drop back down, just assemble the frame on one of the shields, strap in the cargo, and deorbit it. Do it right and the stacks of heat shields and cargo frames will be re-usable.


Centrifuge? Speaking of which, I think we are entirely overdue in finally getting a centrifuge habitat installed on the ISS.

Wasteful.

Why can't any cargo of asteroidal origins just be heat-shielded with the silicate "slag"?  It could be spun as ablative foam or something.

[birdman]

Wasteful.

Why can't any cargo of asteroidal origins just be heat-shielded with the silicate "slag"?  It could be spun as ablative foam or something.

Why heat shield -at all-?

If its a ball of metal 5-10m in diameter, just aim it at the ocean.  You might lose 0.1-1mm of the surface, but...so? 

[Tallpine]

I think we are entirely overdue in finally getting a centrifuge habitat installed on the ISS.

Yeah, I'm a little confused about their semi-random tinker toy model 

I've got this idea for roughly semi-trailer sized cylindrical habitat modules, with swiveling docking hatches at each end.  By the time that you got maybe eight to twelve of them up there in orbit, you could link them end to end like sausages into a circle, and then give it a little nudge to start rotating.

It might be a bit dizzying until you got more modules up there and made a bigger ring, but you could at least have say 1/8 earth "gravity" which would make life more comfortable.

That's also my model for mining camps in the "Belt".  Also thinking we need an ion propulsion "shuttle" or "tug" to transit between the Belt and Terra.  Build it in a stack like a tower, and there would be some positive G force during the constant +/- delta-V.  Only time you would be weightless would be when "parked" near a "camp" or in earth orbit.  If it was modular, then you could push a new habitat unit or other cargo out there, and then load up some resources to return (in a net/cargo module ).  I'm presuming these things will have nuke plant for power supply.

Of course, the best thing would be to process raw materials into finished products right out there in the Belt.  Build your own new habitats as you need the extra space.  Part of the puzzle would be a "greenhouse" to grow food and produce oxygen.  At some point, the whole thing needs to be nearly self sufficient.

[AJ Dual]

Why heat shield -at all-?

If its a ball of metal 5-10m in diameter, just aim it at the ocean.  You might lose 0.1-1mm of the surface, but...so? 

That's what I was also thinking if it's just metals/ore/raw materials too. Or if it's that critical, just form them into some sort of a shape similar to an Apollo/Orion capsule etc. Or a blunted teardrop.

Although I guess I was also thinking about semi-precision items, or perhaps materials that can only be made in microgravity such as alloys that can't be mixed under gravity, or vacuum formed parts, or metal vacuum formed foams that are even more insulative or lighter than ones with air in the voids, that might want a modicum of protection on the way down. They don't need the full protection of a vehicle, but can't just be shot down willy-nilly either.

[Tallpine]

I'm just wondering if you could blow molten metals in space (vacumn/zero gravity) just like you can blow glass into bottle shapes, etc

(no crude jokes please  )

[kgbsquirrel]

That's also my model for mining camps in the "Belt".  Also thinking we need an ion propulsion "shuttle" or "tug" to transit between the Belt and Terra.  Build it in a stack like a tower, and there would be some positive G force during the constant +/- delta-V.  Only time you would be weightless would be when "parked" near a "camp" or in earth orbit.  

I was trying to think of how to do a good habitat for an intrastellar craft. My idea finally boiled down into the sausage link ring that you mentioned earlier, but with the interiors of those links mounted in large ring bearings, that way when the craft accelerates forward the "floors" could tilt a bit, and maintain a stable vertical "gravity" inside the habitats, relative to their internal orientation. A pair of those habitat rings contra-rotating so you can easily spin them up or down to also compensate for the added forward thrust, or lack there of.


@AJ: Ablative slag re-entry shields might work. Still need a parachute and possibly a flotation system though.

[Fitz]

I was trying to think of how to do a good habitat for an intrastellar craft. My idea finally boiled down into the sausage link ring that you mentioned earlier, but with the interiors of those links mounted in large ring bearings, that way when the craft accelerates forward the "floors" could tilt a bit, and maintain a stable vertical "gravity" inside the habitats, relative to their internal orientation. A pair of those habitat rings contra-rotating so you can easily spin them up or down to also compensate for the added forward thrust, or lack there of.

Something like the Reckless Faith with a large armory would be great

[Tallpine]

I was trying to think of how to do a good habitat for an intrastellar craft. My idea finally boiled down into the sausage link ring that you mentioned earlier, but with the interiors of those links mounted in large ring bearings, that way when the craft accelerates forward the "floors" could tilt a bit, and maintain a stable vertical "gravity" inside the habitats, relative to their internal orientation. A pair of those habitat rings contra-rotating so you can easily spin them up or down to also compensate for the added forward thrust, or lack there of.

Well, it would depend on the propulsion system 

I was thinking of a constant thrust at some significant percentage of earth G.  You don't need rotation, just align the floors at right angle to the thrust.  It would probably look sort of like a round tower with many floors and a ladder up the center.  Contrary to the star movies, a spaceship is more like a submarine than a surface vessel, so the control room would likely be at the bottom near the engineering compartment.  Then you would climb up into the living/dining/kitchen level and then on up to the dorms.  Somewhere there would need to be a grow room for long voyages.  At the top or "nose" would be the cargo space and airlocks.  For an intra solar system craft ("tug"), you would probably have a docking system for another module, sort of like a barge or a semi-trailer that you can swap around.  But you would push it instead of pull it.

For a more conventional short boost system (never going to work for any interstellar distance), you just have to strap everyone down and then go back to normal rotation induced "gravity" for the long haul.  Have to figure out how to not tear the thing apart during the "burn."

Or if the "propulsion" is solar wind or extremely small thrust or something yet unknown like some sort of space/time warping, you would just have your normal rotational induced "gravity" because the movement in the direction of travel would be undetectable by the passengers.

Just my speculation ... :)

[AZRedhawk44]

Has there ever been any legitimate scientific discussion on how Star Trek projects a gravity field onto their various ships? 

I wonder with the LHC over in Europe, if some sort of insight into gravity might be gleaned, and a gravity generator improvised in the next 25-50 years.

[Tallpine]

Has there ever been any legitimate scientific discussion on how Star Trek projects a gravity field onto their various ships? 
...

My guess is that they have a guy sitting by himself in a compartment somewhere, reading Russian novels out loud 

 


Seriously, I can't imagine how you would do any such thing, unless perhaps the ship moved in some sort of space/time bubble where everything inside just feels normal.  But then you don't have these cool rockets blasting 

[drewtam]

Has there ever been any legitimate scientific discussion on how Star Trek projects a gravity field onto their various ships? 

I wonder with the LHC over in Europe, if some sort of insight into gravity might be gleaned, and a gravity generator improvised in the next 25-50 years.

I'm not a star trek fan, so I don't know about that.

What I've read of quantum and general relativity, is that we don't really have a good understanding of gravity. We have really good models of it (geometric equations in general relativity) but not a fundamental understanding.

Compare with magnetism... we understand that protons' quarks and electrons have inherit properties that produce electric fields, special relativity can explain how Lorentz transformations produce a "magnetic" force. Or quantum can explain how an imaginary photon is passed back and forth between charged particles, creating the electric and magnetic forces in macro.

For gravity, it is speculated that quantum mechanics should have a "graviton" force carrying particle just like the photon, but it is not proved. How is mass and gravity linked? We think the Higg Boson explains it, which seems to be supported with the latest LHC results.

Or is gravity just an emergent property of entropy? This is a plausible theory with some interesting math. If I understand it correctly, this would make quantum force redundant... so maybe no graviton.
[What do I mean about "emergent"? Friction is a decent analogy. There is no fundamental "friction" force, there is no quantized "fricon" particle for force exchange, even though friction dominates our everyday lives. It is emergent from electromagnetic interactions of molecules to each other.]

So the Higgs Boson research was the next step in gravity and mass research, but we are still trying to prove the fundamentals of how it works and have a lot more to go.

If we ever understand gravity enough to create powerful artificial gravity, using it for easy walking on a ship is the least and most trivial use. That kind of powerful gravity could be extremely important for very fast subluminal travel. And if we can make it astronomically powerful, possibly wormhole travel with permanent gates from one place to another, hopefully we can call them "stargates".

[ArfinGreebly]

I'm just wondering if you could blow molten metals in space (vacumn/zero gravity) just like you can blow glass into bottle shapes, etc

(no crude jokes please  )

Glass is highly viscous.  Metals, not so much.

Might require special pressure environment.

[Hutch]

I can picture steel mills, etc in space.

With virtually no gravity, you could move tons of raw or refined ore around with little effort.  Possibly set up a big parabolic mirror to concentrate the sun's rays and melt the ore.  Molten stuff would form a perfect sphere.  But without any gravity, I'm not sure how or if stuff would separate out 

This has been going on for a while in my mind as I've tried to figure out a possible story idea.  Trouble is that I would have to have the basic engineering figured out before I could write fiction 

Have none of y'all read Live Free or Die by John Ringo?  It's the first of the Troy Rising series, and they all deal with exactly this matter.  So it must be so.  Drill a shaft into a nickel iron steroid, shove a comet into it, then spend years pumping focused sunlight into said nickel-iron asteroid, then voila, the asteroid inflates like a basketball.  You have a Death Star sized globe available for exploitation...  An Iowa-class space battleship, as it were.

[Tallpine]

There is no fundamental "friction" force, there is no quantized "fricon" particle for force exchange, even though friction dominates our everyday lives.

From my study of corporate physics, I postulate the existence of "moron" character 

[erictank]

My guess is that they have a guy sitting by himself in a compartment somewhere, reading Russian novels out loud 

 


Seriously, I can't imagine how you would do any such thing, unless perhaps the ship moved in some sort of space/time bubble where everything inside just feels normal.  But then you don't have these cool rockets blasting 

Inertial damping and gravitic plates. They have MUCH better understanding and control of gravity than we do today.

Interestingly, the Alcubierre "warp drive" that has recently been in the papers appears to work (in a general sense) almost exactly as as you suggest - the warp field moves a bubble of n-space at >>lightspeed (they're suggesting an entry level of ~10c, IIRC, once we figure out how to accumulate several hundred kilos of antimatter to power it); since the space is moving but the ship is not (stationary inside the bubble), relativistic considerations are satisfied.

[kgbsquirrel]

Inertial damping and gravitic plates. They have MUCH better understanding and control of gravity than we do today.

Interestingly, the Alcubierre "warp drive" that has recently been in the papers appears to work (in a general sense) almost exactly as as you suggest - the warp field moves a bubble of n-space at >>lightspeed (they're suggesting an entry level of ~10c, IIRC, once we figure out how to accumulate several hundred kilos of antimatter to power it); since the space is moving but the ship is not (stationary inside the bubble), relativistic considerations are satisfied.

If the relativistic speeds inside the bubble are kept approximate to what we currently are experiencing on Earth, how does that affect time dilation and the like?

[AJ Dual]

If the relativistic speeds inside the bubble are kept approximate to what we currently are experiencing on Earth, how does that affect time dilation and the like?

It would have the potential to be matched. The time differences between the piece of spacetime carried inside a Alcubierre warp would be the same as they'd be before the drive was started up.

So if it snatched a piece of spacetime near the moon and carried it and the ship inside to Vega 25 light years away, the clocks would be in relative agreement on the macro-scale that's important to humans. And in theory, were the warp constructed right, the only difference would have been the original difference between the observer at the bottom of Earth's gravity well, and the piece of spacetime near the moon.

The kind of thing our current satellites and things like the GPS system already take into account.

I know the mass-energy constraints may have been reduced for creating an Alcubierre warp down to just a few hundred kilograms of energy, and some other tricks that may or may not work out might get the exotic matter/negative energy needed down to just a few grams. Although these schemes run into trying to squish things darn close to the Planck length, being several orders of magnitude smaller than a single proton is... tricky, to say the least.

And that of course requires we prove that one of the theoretical exceptions to the Standard Model that provide for Tachyonic/exotic matter is correct rather than one of the one's that don't. So I'm not sure if the LHC will help us out there or not.

Then, there's a kind of chicken-n-egg/Catch-22 problem that may or may not be an issue, that to create the warp, you have to constantly superluminally position the positive/normal mass energy for the gravity well in front of the bubble, but you'd need an Alcubierre drive to do it to start your Alcubierre drive. I'm not sure if the newer scheme to make the drive/field into a torus shape gets around this or not...

Then there are those who posit that operating an Alcubierre drive will sweep up Hawking radiation by separating the virtual particle pairs of the universal quantum foam into "real" ones, much like a black hole's event horizon does, and release a blast of nasty radiation at the destination when it arrives.

Although that might be handy if you don't like the people/things where you're going.  

We were talking about this a few weeks back, and a few of us were wondering if maybe it would be a good candidate for non-radio SETI, that if such warp drives are possible, and advanced species use them, we might be able to see the gamma bursts of the collected Hawking radiation from the arrivals.

[birdman]

@AJ: Ablative slag re-entry shields might work. Still need a parachute and possibly a flotation system though.

If you are trying to bring back metal, or actually ANY homogeneous material, you don't need heat shields, parachutes, or floatation.   My point was the surface loss is quite low, even on low angle trajectories, and as far as parachutes or floatation, why?  We pick stuff up off the ocean floor all the time (cable laying, etc), the ball of whatever is going to sink "approximately" straight down (it won't drift much due to its high ballistic coefficient).

So you aim for a low angle re-entry, if its a sphere it will at most low hypersonic when it hits, but if a ball of stuff, it won't break up, so you aim for say a 100km diameter target zone, track the big flaming ball optically or with radar, sail over to where it hit, sonar search for a big ass ball on the ocean floor, grab it and haul it up.

Easier than somehow packaging parachutes or floats to both survive re-entry AND float a 1000 ton ball.

[Tallpine]

If you are trying to bring back metal, or actually ANY homogeneous material, you don't need heat shields, parachutes, or floatation.   My point was the surface loss is quite low, even on low angle trajectories, and as far as parachutes or floatation, why?  We pick stuff up off the ocean floor all the time (cable laying, etc), the ball of whatever is going to sink "approximately" straight down (it won't drift much due to its high ballistic coefficient).

So you aim for a low angle re-entry, if its a sphere it will at most low hypersonic when it hits, but if a ball of stuff, it won't break up, so you aim for say a 100km diameter target zone, track the big flaming ball optically or with radar, sail over to where it hit, sonar search for a big ass ball on the ocean floor, grab it and haul it up.

Easier than somehow packaging parachutes or floats to both survive re-entry AND float a 1000 ton ball.

Just adding that as I remember the Gulf of Mexico is a pretty big target and also pretty shallow :)

[birdman]

Just adding that as I remember the Gulf of Mexico is a pretty big target and also pretty shallow :)

Too close to land, and shallow isn't good, it coud bottom out.

Besides, if you are mining right, the sphere would be 10-20m in diameter, have a mass of up to 30,000 tons, and hit with several kilotons of energy even at subsonic speeds, and likely 10-30kT if mach 5-6 which would be easier.  That's quite a wave, and it will penetrate 500-1000ft before really slowing down.