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Tom Kalbfus

Banned

Registered: 2006-08-16

Posts: 4,401

The Rama Starship: Can we build it?

http://www.bing.com/videos/search?q=Ram … &FORM=VIRE
This is not the Rama from Arthur C Clarke's Rendezvous with Rama, that Rama was built by Aliens, the Rama shown in the video above was built by humans, and was built for humans, it is much greener than Clarke's Rama, and there was an island in the Cylindrical Sea that reminded the protagonist of Manhattan, so he called it "Manhattan" but that was just because it had a bunch to tall buildings, it wasn't modeled exactly on Manhattan as shown in this video. Rama has a shape of cylinder of length 54 km and internal diameter 16 km. The Rama in the video has those dimensions, but the particulars are human oriented, there is an actual replica on manhattan, their are trees and highways etc, as if it were designed and build for humans.

This is the Rama of Clarke's Novel. Looks a bit spare doesn't it. Has a metal floor where nothing can grow, no trees, no highways etc, and the Manhattan there is obviously not our Manhattan.

So lets assume we build it according to these specifications, but design it for humans. First question is it big enough? Can it get us there? Aside from the magical engine described by Clarke, what would be a realistic engine for this thing? This thing would rotate once every 4.23 minutes to produce 1 gravity. How fast would you want it to go? Clarke's Rama accelerated unrealistically hard for a starship this size, in fact it accelerated so hard, it didn't need to be an Ark Ship! A realistic Rama would accelerate gradually, probably a fraction of a gee. The primary gravity is produced by spin, you don't want to tear up the landscape with hard accelerations, do you.

Antius

Member

From: Cumbria, UK

Registered: 2007-05-22

Posts: 1,003

Re: The Rama Starship: Can we build it?

Basically an O'Neill colony and a fusion power supply to provide energy during transit.  We cannot build it because we cannot build O'Neill colonies at present technology sets or fusion power supplies.

Tom Kalbfus

Banned

Registered: 2006-08-16

Posts: 4,401

Re: The Rama Starship: Can we build it?

I think mainly its because we could not get the required mass into orbit at present. It is 54 km by 16 km in diameter, in terms I'm more familiar with its 34 miles long and 10 miles wide. if we unroll this cylinder we have a rectangle that is 34 miles long and 31.42 miles wide, that is 1068.28 square miles. An O'Neill Island Three Cylinder is 20 miles long and 4 miles wide, giving us 251 square miles per cylinder before you subtract half for the Solar windows to let in sunshine, So basically a pair of two Island Three Cylinders equals one quarter the land area of a single Rama Starship. The folk at NSS say that a Titanium hull would be strong enough to hold the cylinder together under that centrifugal force. The Light Source for the Rama Cylinder looks to be artificial, essentially they are giant light bulbs of some sort, something that can deliver the equivalent of sunshine to the interior of the cylinder, they also take up less land area than O'Neill's windows. I imagine would would not want to be standing next to these giant light sources when they are on, as they would generate a lot of heat. I imagine that for safety you might want to build reflective walls around them s they shine most of their light into the opposing landscape. Air is mostly transparent to visible light, so the light will pass through that, reflect off of clouds, and when it I absorbed by some surface, such s the ground, it will be reradiated as heat.

This picture shows the light sources, they look like giant plasma tubes. I think they would not be as bright to look at as staring directly at the sun, since their total illumination has to add up to the Sun as seen from Earth, and that brightness is spread our over long tubes instead of one round disk in the sky. The Cylindrical sea is a break in that lightning, but enough light spills over to illuminate it and the replica of the island o Manhattan. I suspect most of the residents would live on than Manhattan replica, the surrounding country side would b used to grow food. Every street and avenue on Manhattan Island has its counterpart in the Manhattan replica. I think if you or I were walking around among those buildings, some things would look familiar, some things would look different. You have for instance the Twin Towers still standing, the floors of those buildings would probably be used for different purposes than the original, as there would not be as much "World Trade" inside the Rama Cylinder.

I think there may be a Grand Central Station on 42nd street, there maybe trains to other parts of the cylinder from there, I think they would mostly be subway trains though. No use in having rail road crossings if the entire landscape is artificial. There would be a Brooklyn Bridge, although it would lead to farmland instead of Brooklyn. The Outer Boroughs are entirely missing, so the population would be less than the Greater New York Area, and consequently that means less traffic in the streets. In this New Manhattan, it would be easier to find a parking spot, and you spend less time stuck in traffic jams. The Automobile would only supplement a mass transit system that runs the entire length and breadth of the cylinder, with subway stations popping up amongst farms and the like. But if one likes to travel those roads in one's car, one can do so. I sort of doubt those cars would run on gasoline, probably on hydrogen fuel cells or electric batteries. Recharging stations should be quite plentiful, all the energy ultimately comes from the starship in any case.

Probably the ship would accelerate at a fraction of Earth's gravity, possibly by under 1 percent, buildings and structures would have to be buttressed with withstand this acceleration, the landscape will seem to tilt slightly when the ship is accelerating. The cruse velocity would be between 1% and 5% of the speed of light. One has to take into consideration the potential population increase within the cylinder during this journey, so it can't be allowed to stretch past a couple of centuries. the Ship will probably maintain contact with Earth during this time, it certainly is big enough to receive radio signals. Propulsion would probably be fusion, larger fusion reactors would be more efficient, maybe even pulse fusion.