Starviking
SOC-13
Sounds good to me. I guess the Cooperative might even have selected the asteroids by composition in order to provide maximum-self sufficiency.
Astounding engineering feat
- Thread starter rancke
- Start date
Sounds good to me. I guess the Cooperative might even have selected the asteroids by composition in order to provide maximum-self sufficiency.
Yeah, that's a good point. The vapour pressure of iron at its melting point is almost a twenty-thousandth of an atmosphere, and you would need quite a column to provide that in asteroidal microgravity. I guess the big issue is Jeans Escape: the escape velocity of a small asteroid is less than the mean molecular velocity of iron vapour at 1811 K, so Jeans escape will prevent the column of iron vapour from accumulating.
Let's consider an iron asteroid with a density of 7700 kg/m3 and a diameter of 500 m. Escape velocity is Ve = √(2 G M / R) = 0.52 m/s. Meanwhile, root mean square velocity of molecules in a monatomic gas is v(rms) = √(3 R T / M), which for iron (M = 0.056 kg) at 1811 K is v(rms) = 895 m/s — 1720 times escape velocity.
We're going to need 3,180 gee of artificial gravity just to retain the mean molecule. Or a much larger asteroid.
I wonder how fast it boils. With free energy to do the heating we could perhaps afford to let most of it boil away while we were waiting for the centre to melt.
Last edited:
Peter Schutze
SOC-12
{quote}As far as I understand it, asteroids are not solid bodies, and certainly not bodies with structural strength comparable with engineered structures. <snip>
Now, a meteroid is a different story, being a boulder, a coherent chunk of rock bound by its mechanical strength.{/quote}
my thoughts were more related to Vesta, Ceres etc .... the top 10-20 rocks by size which mostly have enough gravity to start to differentiate etc
put 90% of the mass of the belt into close proximity (but not close enough to suffer noticable gravitational effect) in some aesthetically pleasing arrangement and manipulate them to increase their Mk1 eyeball visibility .... clearly artificial and the obvious "capital" of the belt
Now, a meteroid is a different story, being a boulder, a coherent chunk of rock bound by its mechanical strength.{/quote}
my thoughts were more related to Vesta, Ceres etc .... the top 10-20 rocks by size which mostly have enough gravity to start to differentiate etc
put 90% of the mass of the belt into close proximity (but not close enough to suffer noticable gravitational effect) in some aesthetically pleasing arrangement and manipulate them to increase their Mk1 eyeball visibility .... clearly artificial and the obvious "capital" of the belt
My comment, which you quoted, was addressed to Rancke2's suggestion of putting a spin on and asteroid or asteroids to provide pseudogravity. That would certainly not be possible with a large object like Ceres, Pallas, or Vesta. The fact that even their feeble gravity has drawn them into ellipsoidal shape shows that the material that makes them up has practically no rigidity on the scale of their size. If you were to spin one of those objects so as to produce net centrifugal pseudogravity it would surely become indefinitely prolate in shape (i.e. fly apart at the equator).
Last edited:
Enoki
SOC-14 1K
How about something like in the anime Vandread? The "outpost colony" that appears in several episodes is a space station that has a large number of thethered asteroids attached. These are on the end of what appear to be cables sort of like space elevators.
If the whole of this was spinning it would impart gravity on the mass. In addition, the asteroids thethered could be more readily mined using the cables as cable car ways. The station could be part factory, part city.
If the whole of this was spinning it would impart gravity on the mass. In addition, the asteroids thethered could be more readily mined using the cables as cable car ways. The station could be part factory, part city.
far-trader
SOC-14 10K
Thanks for bumping this Enoki... I wonder if this would qualify?
I'm re-reading some classic/golden age sci-fi. Into the middle of Med Ship at the moment and the ship has just come across a bit of an engineering feat. A band of highly reflective dust particles put into position to reflect some of the star's heat back to warm up a cold world in the outer habitable zone. The author notes it might be potassium or sodium, and would only need "tens or scores of tons". It would be light enough to easily seed the band, but massive enough to resist easy dispersal by solar wind. I'd expect it would have to be reseeded over time but it wouldn't take much.
Sounds pretty cool (warm
) and doable at an early tech/colonization level but still valued, needed, and well regarded ages later. Plus it makes one heck of a display in the system and alters the stellar property observed from afar if the band is eclipsing the star, reading cooler/dimmer than normal.
I'm re-reading some classic/golden age sci-fi. Into the middle of Med Ship at the moment and the ship has just come across a bit of an engineering feat. A band of highly reflective dust particles put into position to reflect some of the star's heat back to warm up a cold world in the outer habitable zone. The author notes it might be potassium or sodium, and would only need "tens or scores of tons". It would be light enough to easily seed the band, but massive enough to resist easy dispersal by solar wind. I'd expect it would have to be reseeded over time but it wouldn't take much.
Sounds pretty cool (warm
) and doable at an early tech/colonization level but still valued, needed, and well regarded ages later. Plus it makes one heck of a display in the system and alters the stellar property observed from afar if the band is eclipsing the star, reading cooler/dimmer than normal.FYI, Vesta and Ceres actually are likely to be differentiated:
http://www.nature.com/nature/journal/v437/n7056/abs/nature03938.html
Sedna (and other 'dwarf planets') are likely to have differentiated into at least an icy crust/mantle and rocky core.
Vesta is definitely not spherical, but Ceres and Sedna are big enough to be (Ceres is known to be, from Hubble images).
Enoki
SOC-14 1K
Far-Trader,
I would think that a very large space station that had as many as maybe 50 large asteroids tethered to it at various distances spinning in a stable orbit and a gravity that approached 1G as a result would be a rather impressive sight taking up some considerable amount of space. It might look like almost like a planetoid (the station could of course be a large asteroid itself in whole or part) with an impressive ring circling it.
For a moderate tech level it would be an impressive achievement not to mention a relatively good economic one if extensive mining of minerals was going on with the various asteroids being replaced as they were used up.
I would think that a very large space station that had as many as maybe 50 large asteroids tethered to it at various distances spinning in a stable orbit and a gravity that approached 1G as a result would be a rather impressive sight taking up some considerable amount of space. It might look like almost like a planetoid (the station could of course be a large asteroid itself in whole or part) with an impressive ring circling it.
For a moderate tech level it would be an impressive achievement not to mention a relatively good economic one if extensive mining of minerals was going on with the various asteroids being replaced as they were used up.
Take a large asteroid that is mainly (80% +) iron ore.
Core it out, stuff it full of ice then seal the end.
Heat the asteroid up while also spinning it slowly in 3 directions.
If done properly you will have a large hollow sphere with a very thick iron ore wall.
(from a story in the Analog magazine.)
Dave Chase
Core it out, stuff it full of ice then seal the end.
Heat the asteroid up while also spinning it slowly in 3 directions.
If done properly you will have a large hollow sphere with a very thick iron ore wall.
(from a story in the Analog magazine.)
Dave Chase
far-trader
SOC-14 10K
I guess I wasn't clear enough, my question was directed to my own musings, not yours, and not about the impressiveness but of the suitability for the OPs needs. I agree yours fits the impressive requirement
Take a large asteroid that is mainly (80% +) iron ore.
Core it out, stuff it full of ice then seal the end.
Heat the asteroid up while also spinning it slowly in 3 directions.
If done properly you will have a large hollow sphere with a very thick iron ore wall.
(from a story in the Analog magazine.)
Dave Chase
Can you quote the issue and title? Sounds like an interesting read.
Thanks.
Hmm, heat it enough and it will explode as the steam expands. But really, if you core it you already have a hollow sphere with an iron ore wall...
Nope.
But I can give you another story reference more recent
Live Free or Die by John Ringo
pg 289-292
Dave Chase
Nope.
But I can give you another story reference more recent
Live Free or Die by John Ringo
pg 289-292
Dave Chase
That's one of his I haven't read yet. I'll have to check it out (even though Ringo is really getting predictable and boring... good writer, though.
Thanks again.
