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The scale, it boggles

In doing some writing recently, I decided to check a few things with a friend and with Google. And with a calculator. I've known the time scale of Traipah's civilization for over a decade, but I found some stuff today that boggles my mind... Given that the Reformation happened 10 thousand years before 3232 AD, that means that the underground cities that the early Yahgahn church built all around the planet Traipah prior to the Reformation were built in about the 6700's BCE. The train system interconnecting these cities was built within 1000 years after the Reformation, and hasn't significantly changed in terms of technology in all that time, with the exception of the crystalanium tunnels they built under the oceans to connect the continents. The underground train system predates not only the fall of Rome, it predates the rise of Rome as well! And since that happened *after* the Reformation, it means that Traipahni people were regularly mining asteroids for metal while the civilization of Ancient Egypt was still young.

What's more, I looked at that, and then looked again at the scale of the rest of Traipahni civilization. I did some Googling, and found out that the Ah'Koi Bahnis and Duenicallo would have been building cities and making systems of writing before Homo sapiens even evolved! Their civilization predates our entire species.

Now I'm even more determined to write a scene or a short story wherein some human is being superior to the Traipahni people for re-introducing them to space travel, because now I can have the AKB defending her people dropping bombshells like that! "Fuck you! My people were mining asteroids when yours were just beginning to invent the mud brick! My people were building cities to rival Rome before your species even evolved!" :-D

Pretty much the only reason they took so long to go back into space after the Reformation was because they were stuggling to find a way to get into orbit without using dangerous, pollution-causing chemicals.

This was cross-posted from http://fayanora.dreamwidth.org/1089621.html
You can comment either here or there.

Comments

( 6 comments — Leave a comment )
wizwom
Jun. 8th, 2012 03:17 am (UTC)
Orbit without chemical rockets is easy, just use nuclear electric resistojets.
kengr
Jun. 8th, 2012 05:25 am (UTC)
Nuclear heating (done directly by the reactor) is going to be a lot more efficient.
wizwom
Jun. 8th, 2012 02:43 pm (UTC)
Well, yes - if you can control radioactivity.
you can use the waste heat from the power plant as a preheater for the exhaust, and recover close to 90% of the enthalpy.
But a heating chamber can reach much higher temperatures than a nuclear core, since you don't have to worry about the nuclear material properties. So you actually end up with better thrust to weight and better ISP from resistojet.
kengr
Jun. 8th, 2012 04:41 pm (UTC)
Converting heat from the reactor to electricity and back again is a *major* loss of efficiency.

As for temperature, even the old NERVA reactors operated at quite high temps with few problems. When the reactor is essentially a sold block of ceramics with gas channels thru it for the hydrogen to flow thru you can reach some pretty high temps.

As I recall, they had more problems avoiding erosion of the gas channels from the high fuel flow rates than from temperature. Since he plutonium was in the form of plutonium oxide, rather than metallic Pu, they didn't have to worry about it melting.

There are plans for liquid core reactors and even gaseous core ones to get even higher temps. Dunno if anybody has actually built test models, though.

And, of course, magnetic confinement fusion reactors would give insanely high temps. Old NASA chart gave an estimate of 600,000 for the ISP of a fusion rocket.
fayanora
Jun. 9th, 2012 12:14 am (UTC)
Wouldn't that be dangerous and a potential environmental hazard?
kengr
Jun. 8th, 2012 05:25 am (UTC)
Depends on what you consider pollutants.

Hydrogen/oxygen rocket engines produce water vapor as the exhaust. Ones using hydrocarbons as fuel add CO2 to the mix.

The solid rocket boosters that the space shuttle used had aluminum in the fuel as well. The thick white smoke was aluminum oxide. White will precipitate out of the atmosphere without too many problems. Of course, solid fuel rockets aren't recommended for manned space craft. Only reason the shuttles used them was that Congress wouldn't pay for the liquid fueled booster design.

Various nuclear powered designs exist. They'd give better performance, and frankly, even if sabotage made them blow up, you'd have large chunks of *very* non-reactive ceramics as the radioactive debris. And the fuel would be hydrogen. Which would react with the atmosphere to form water *after* leaving the engine.

An air-breathing nuclear "jet" (look up the old USAF Project Pluto) could be used as a booster, but that might result in *some* radioactive nitrogen & oxygen. But not a lot.

If you've got fusion reactor that are continuous high temp fusion, not one of the "low temp" things like a Farnsworth Fusor, or one of the pulsed inertial confinement designs, you get an even more efficient rocket using the reactor to heat hydrogen fuel.

The nuclear rockets (fission or fusion) heat hydrogen. Which mostly winds up as water. The chemical rockets using oxygen & hydrogen also have water as the exhaust. Since the hydrogen in all of those comes from water, that means they aren't pollution.

The chemical rockets burning hydrocarbons, do release CO2, but that's only pollution if the hydrocarbons are from fossil sources. If they are from plant sources, then they are carbon neutral.

Besides rockets, there are several launch methods that just require a lot of electrical power on the ground, launch loop, space fountain, and laser launch.
( 6 comments — Leave a comment )

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