[ot] Mars colonization

[Storminator]

Not indestructible - hard to destroy. Running an airplane into the cable won't sever it. <SNIP>

What is the cable made of? There's nothing made right now that can hold up to those stresses. Can you imagine the forces acting on that cable? An ariplane just might sever the cable, depending on the strain it's under to begin with.

The danger to the elevator is a meteor hitting the cable near the station, or hitting the station itself. Then the cable, anchored at the base, lays down. Remember, a space elevator has the station in geosync orbit...40000+ km away. The cable wraps the equator!

All that aside, the real deterrent to a space elevator is cost. I've seen estimates of 10 billion USD, assuming we invent new materials, have no unforeseen engineering problems, and no redesigns. All that says to me: closer to half a trillion dollars. You need to lift a LOT of material into space to make that money back.

PS

 

[Sir Hawkeye]

OK, let's see, how about some replies to points brought up thus far.
Commo: Always gonna be problem. "I canna change the laws of physics, Cap'n!" Nuff said.
Shipping: From the moon to earth is actually pretty easy. It's called magnetically fired shipping containers with parachutes. Real tough. The moon has a substancially lower speed requirement for breaking of it's gravity.
Earth to other places: That's where we are going to have to expand technology, or do some good thinking. It can be done, and many people far smarter than I ahve theorized ways to do this.
Budget: Oh yes. Slash the Defense Budget. Why is that always the first answer to everything? How about slashing other budgets instead of slashing a budget on something that is [edited to remove politics] What about cutting politicians pay? Big savings there. I can think of plenty of places to cut, and the Defense Department would be last. Why? Simple. We'll still need American soldiers and military technology advancements here on Earth.
Going there: I'll go. I'll take my kids and wife. You sit on earth and suffocate from the over-population. Give me a base gene pool of 150 couples (That's 300 people) and as far as I'm concerned, we'll never allow anyone else to show up! But I'm greedy! A lot of us would go there, thrive off of the hardship and conditions, and rise to the challenge.

Here's one problem though: If some dummy dies, when we're trying to colonize Mars, how quick do you think the program would be shut down in America?
Can you say: Lightspeed?

On the Defense Budget: all politics aside, the military budget is by far the largest portion of the US budget. e.g, $30 billion is 10% of the defense budget, but it wipes out other categories of spending. General government is the second largest cost, but vast payroll cuts to civil service workers could be difficult.

Granted, I don't know what percentage of military spending is pure maintenance as compared to research, nor do I know the relevancy of all the projects being researched. Theoretically, modest cuts to military research (and I do mean modest: I am a firm believer in maintaining technological superiority) would produce more capital than most other single methods.

 

[Umbran]

the thickness of a common rope that was strong enough to survive an atomic attack

Methinks this is vastly overstated. Even carbon nanotubes are held together by mere chemical bonds. Direct application of nuclear weapon energies is enough to dissociate any such bonds quite easily. We're talking the temperatures reached within the core of a star, where matter is all ionized - you have no nanotube if none of those carbon atoms have electrons.

Remember - tensile strength and ability to abosrb energy are not the same thing.

 

[tleilaxu]

personally, i think we should practice putting some asteroids into earth orbit before we start building space elevators.

Also, i disagree with Wil who stated terrorism was not a good reason to not build a space elevator. NO ONE has ANY idea what kind of damage a falling elevator would cause, not only locally around the equator, but also globally and environmentally.

 

[Wil]

Also, i disagree with Wil who stated terrorism was not a good reason to not build a space elevator. NO ONE has ANY idea what kind of damage a falling elevator would cause, not only locally around the equator, but also globally and environmentally.

My contention is that any terrorist group capable of mounting an operation that would take down a construct like an orbital elevator is one that we should be afraid of PERIOD. This isn't three people piloting planes, this is an organized, well equipped army that is intent on mass devastation of the planet to accomplish their goals. That's an organization that I'd be concerned about, space elevator or no.

As for no one having any idea about the impact

http://www.highliftsystems.com/faq.html

 

[Storminator]

On the Defense Budget: all politics aside, the military budget is by far the largest portion of the US budget. e.g, $30 billion is 10% of the defense budget, but it wipes out other categories of spending. General government is the second largest cost, but vast payroll cuts to civil service workers could be difficult.

Granted, I don't know what percentage of military spending is pure maintenance as compared to research, nor do I know the relevancy of all the projects being researched. Theoretically, modest cuts to military research (and I do mean modest: I am a firm believer in maintaining technological superiority) would produce more capital than most other single methods.

I believe the US spends roughly 80% of the worlds' military R&D (some of it to pay my salary ). Consider how much countries like India and Pakistan are spending to replicate very old US technology: US military research is much more fruitful than anyone elses.

Research spending still isn't that big a share of military spending. Buying equipment and paying troops are still the lion's share of spending.

And FYI, the 4 biggest categories of the US gov's budget are military, interest on the debt, Social Security, and Medicare. The order varies from year to year. Note that none of the those categories are very flexible.

PS

 

[Storminator]

<SNIP>
As for no one having any idea about the impact

http://www.highliftsystems.com/faq.html

I'm rather skeptical of the claims of these people. They seem rather dismissive of risks and enthusiastic about benefits. For example, this mythical cable can withstand the impact of a 2 inch meteor, yet will completely disintegrate if the cable falls.

PS

 

[Wil]

The impact of a two inch meteor doesn't come anywhere near the force of 20 tons of cable slamming into the Earth's atmosphere at a tremendous velocity [edit: make that "tremendous velocity" 7km/s]. The friction by itself would disintegrate the cable. Once it started to come unwound, the actual fibers themselves are about the thickness of a hair.

Real world example: a two inch meteor would punch a hole in the space shuttle. On the other hand, the space shuttle hitting the Earth's atmosphere at too flat of a trajectory would cause it to completely disintegrate. The cable will weigh only 20 tons. The dry weight of a space shuttle is 90 tons, and I can assure that little would survive to hit the ground.

 

[tleilaxu]

Also, I don't think a space cable will be built on earth until we have a permenant presence on the moon or mars. Where should we send all this stuff we shuttle to space? There has to be a destination, a back and forth. We need a colony on mars and space cables on each planet.

Re: Terrorism

With the current proliferation of WoMD more and more groups will have access to ballistic missles or something else to attack the elevator. In 1945, one country had nuclear missles, these days a third-rate country like North Korea is almost there. In 2050 a country as small as Jamaica could conceivably have them (ok, that's a stretch).

tleilaxu imagines the "Rasta Bomb"

 

[Wil]

Not necessarily. The elevator drastically reduces the cost of getting materials into orbit. This includes prefab parts for spacecraft. An elevator may be what's needed to economically get a colony on Mars or the Moon.