Space Elevator

[PMN1]

Quite a lot of the questions regarding the cable falling, generating an electrical charge are in the various links i have posted including...

http://uplink.space.com/showflat.php?Cat=&Board=businesstech&Number=159176&page=0&view=collapsed&sb=5&o=0&fpart

 

[Mr_ Bondoc]

Consider This...

Where are you getting the 2 billion deaths from? If there was a break, most of the ribbon would burn up in the atmosphere and the anchor itself is out in the middle of the Pacific.
As for the Yangtze River Dam, you didn't include the rampant corruption so I wouldn't count that as a resonable comparison.
With the static electricity, part of it depends on what KIND of nanotubes are being used. Some types are conducting and some are insulating.

-Consider that a ton of metal , especially with the nanotube insulation, will be able to disperse the heat effectively like a heat shield. As such, when the ton of metal, traveling at terminal velocity hits the surface of the planet from a near orbital height, the initial force is like a Hiroshima-class nuclear weapon. To make matters worse, consider that you have the object rising to 150 kilometers and 500 m on each side of the object, at least according to NASA models....


-As for delays in construction, consider that the Hoover Dam in the U.S. had construction delayed for 6 months when funding dried up temporarily in 1932. Consider that a similar problem happened with the Aswan Dam when it was finally constructed in 1970, consider that intial construction was delayed for two years, after disagreements erupted between Egypt and the USSR. As such, the delays are a major concern. Also consider the English/French Channel Tunnel suffered over 10 years in construction delays due to American and British financing starting in 1986, until its completion in 1998....

 

[Max Sinister]

One counter-argument:
Oxygen is no matter, since I guess they would rather use remote-controlled robots for the work. Saves a lot of hassle.

 

[Mr_ Bondoc]

Problem...

One counter-argument:
Oxygen is no matter, since I guess they would rather use remote-controlled robots for the work. Saves a lot of hassle.

Consider that each robotic worker will cost at least $750,000 each, based on software, IP techinical training, anti-viral protection, EM protection, stability and motion trackers, corporate liability insurance, and fuel/battery consumption.

Also consider that you would have political and legal pressure to include human workers on the project. Consider that in the United States alone, you would have the AFL-CIO and SEIU launch a major protest over the denial of jobs. In the Third World, consider that organizations like the Sendero Luminoso (Peru) or Al-Qaeda, would use the lack of human workers as a sign of "exploitation of the Third World and the working classes..."

 

[DominusNovus]

Consider that each robotic worker will cost at least $750,000 each, based on software, IP techinical training, anti-viral protection, EM protection, stability and motion trackers, corporate liability insurance, and fuel/battery consumption.

Also consider that you would have political and legal pressure to include human workers on the project. Consider that in the United States alone, you would have the AFL-CIO and SEIU launch a major protest over the denial of jobs. In the Third World, consider that organizations like the Sendero Luminoso (Peru) or Al-Qaeda, would use the lack of human workers as a sign of "exploitation of the Third World and the working classes..."

You know, so much of what you're saying applies only to present conditions. You have no idea how much robots will cost when the elevator is actually built.


AND STOP SAYING CONSIDER!

 

[emperorharry86]

IF the space elevator did fall, it would kill no one...the 2 billion number is ridiculous!

 

[Aldroud]

-Considering the sheer size and the amount of static electricity generated by the elevator, wouldn't one possible danger be the creation of a large electrical storm system that would hover over the region. Consider while the electricity wouldn't damage the tower, a permanent electrical storm system could seriously damage global weather patterns....

Uhhhh...
Didn't I just address that point? Did you even bother reading what I said?

-Considering one ton of metal dropped from space has the same explosive force as a Hiroshima-class nuclear weapon, there are two problems. First, whats to prevent a terrorists from dropping large objects from the top of the tower, killing thousands, if not millions of people? Also, who would want to live around a tower and/or building wherein whether by accident or by terrorist attack, everything for 75 miles could be annihilated?

No, I guess you didn't read what I wrote. What metal tower? And it's 230 miles offshore, so no one living nearby. Tether defended by US Navy, now terrorists are committed, but they're not stupid.

-Consider that if the tower collapses, 2 billion people are going to be killed within 24 hours. As such, who would be willing to take on the insurance liability? Consider that the costs of insurance for the entire project from terrorist attack could bankrupt the entire venture. To make matters worse, what happens when cost overruns cause delays in the construction. Just consider that construction on the Yangtze River Dam was halted at least 6 times , for a total of 8 months due to various lawsuits, labor disputes, and concerns of environmental damage....

Did the monkey pick 2 billion from the crack of its ass and tell you this? What 2 billion? Any catastrophic failure would result in a fine carbon ash wafting to earth.

 

[Mr_ Bondoc]

Uhhhh...
Didn't I just address that point? Did you even bother reading what I said?

Actually I was looking at the basic physics in the natural development of an electrical storm. Just look at Wikipedia:

Lightning has been triggered directly by human activity in several instances. Lightning struck the Apollo 12 soon after takeoff, and has struck soon after thermonuclear explosions. It has also been triggered by launching rockets carrying spools of wire into thunderstorms. The wire unwinds as the rocket climbs, making a convenient path for the lightning to use.

http://en.wikipedia.org/wiki/Lightning

Consider that the construction of the space elevator will cause a similar effect for lightning strikes....

No, I guess you didn't read what I wrote. What metal tower? And it's 230 miles offshore, so no one living nearby. Tether defended by US Navy, now terrorists are committed, but they're not stupid.

Remember the USS Cole (10/12/2000), the last time I checked they had been able to successfully blow a 40'X40' hole into a U.S. naval vessel in Yemen? Or how about the USS Pueblo which was captured by the North Korean military, with 79 Naval officers (1/23/1968)? Or how about the 42 U.S. naval officers killed aboard the USS Stark by Iraqi shoulder-launched missiles (5/17/1987)? Terrorists and rogue states will take whatever steps are necessary to get their point across...

Did the monkey pick 2 billion from the crack of its ass and tell you this? What 2 billion? Any catastrophic failure would result in a fine carbon ash wafting to earth.

For those who are interested, I'll calculate the terminal velocity for a sphere that has a radius of 10 cm. I'll assume the sphere has a density of 1 gm per cubic centimeter, i.e. it is similar to that of water. The physics equation for the force on an object depends on the shape of the object, and so we pick the sphere because the shape has a simple equation. For the sphere, the force is given by

F = (1/2)A r v2

In this equation, F is the force, A is the area of a circle (that's what the sphere looks like to the wind: A =p r2), r is the density of air = 0.001 gm per cubic cm, and v is the velocity.

The force of gravity is given by F = mg, where m is the mass and g is the gravitational constant. For typical physics units, we will use A in square centimeters, p in grams per cubic centimeter, v in centimeters per second. For these units, g = 980 = 1000 (approximately). The object falls faster and faster until the force of gravity equals that of the air. So we take the equation above and set it equal to F = mg. This gives

(1/2)A r v2 = mg

Now we substitute m = (volume)*(density), take the density of food = 1 gram per cubic centimeter, and use volume of sphere = (4/3)pr3. This gives the following equation:

(1/2)(p r2)r v2 = (4/3)pr3g

Plugging in the numbers, and solving for the velocity v, gives v = 5000 cm/sec. Using the fact that there are 3600 seconds in an hour, 100000 cm in a kilometer, and 1.6 km in a mile, we convert this velocity, and get that it is approximately equal to 100 miles per hour.

An object falling from a height of 30,000 ft would reach a velocity close to 1000 miles per hour, i.e. ten times faster. (And at 10x the speed, it would carry 100x the explosive energy. Considering you have metal hitting the surface at terminal velocities, you have your near-nuclear explosion and consideringt the amount of metal to hold up such a structure, and the area of the world chosen (e.g. Singapore), that's how you get 2 billion people killed....

So if you don't like the numbers...Do the friggin math!!

 

[Max Sinister]

2 million, ok, but 2 billion? 2,000,000,000? That's one third of the world population. Would the falling elevator cause a nuclear winter or something like that?

 

[Aldroud]

Oh God, I have a headache already.

Actually I was looking at the basic physics in the natural development of an electrical storm. Just look at Wikipedia:

Not the most reliable nor factual reference you could come up with considering it's open sourced information. I know of several instances where Wikipedia information turned out to be spoofed or altered.

The wire unwinds as the rocket climbs, making a convenient path for the lightning to use.

NO THAT"S NOT HOW IT WORKS. The wire decends to earth from space, not trailed by a rocket!!!

Remember the USS Cole (10/12/2000), the last time I checked they had been able to successfully blow a 40'X40' hole into a U.S. naval vessel in Yemen? Or how about the USS Pueblo which was captured by the North Korean military, with 79 Naval officers (1/23/1968)? Or how about the 42 U.S. naval officers killed aboard the USS Stark by Iraqi shoulder-launched missiles (5/17/1987)? Terrorists and rogue states will take whatever steps are necessary to get their point across...

Actually I do, I was in the middle east at the time of the Cole. So, lets see, you are equating an incident that takes place in a supposedly friendly port, a factually incorrect statement about Iraqi shoulder fired missiles (Exorcet missile is French made, launched from an aircraft, and weighs a quarter ton, not exactly man portable, but I digress) In open water, NO ONE gets near a U.S. aircraft carrier without being tracked for hundreds of miles. The one constant about American warfighting capabilities is 'if you can see it you can hit it and if you can hit it you can kill it'.

For those who are interested, I'll calculate the terminal velocity for a sphere that has a radius of 10 cm. I'll assume the sphere has a density of 1 gm per cubic centimeter, i.e. it is similar to that of water. The physics equation for the force on an object depends on the shape of the object, and so we pick the sphere because the shape has a simple equation. For the sphere, the force is given by

F = (1/2)A r v2

In this equation, F is the force, A is the area of a circle (that's what the sphere looks like to the wind: A =p r2), r is the density of air = 0.001 gm per cubic cm, and v is the velocity.

The force of gravity is given by F = mg, where m is the mass and g is the gravitational constant. For typical physics units, we will use A in square centimeters, p in grams per cubic centimeter, v in centimeters per second. For these units, g = 980 = 1000 (approximately). The object falls faster and faster until the force of gravity equals that of the air. So we take the equation above and set it equal to F = mg. This gives

(1/2)A r v2 = mg

Now we substitute m = (volume)*(density), take the density of food = 1 gram per cubic centimeter, and use volume of sphere = (4/3)pr3. This gives the following equation:

(1/2)(p r2)r v2 = (4/3)pr3g

Plugging in the numbers, and solving for the velocity v, gives v = 5000 cm/sec. Using the fact that there are 3600 seconds in an hour, 100000 cm in a kilometer, and 1.6 km in a mile, we convert this velocity, and get that it is approximately equal to 100 miles per hour.

An object falling from a height of 30,000 ft would reach a velocity close to 1000 miles per hour, i.e. ten times faster. (And at 10x the speed, it would carry 100x the explosive energy. Considering you have metal hitting the surface at terminal velocities, you have your near-nuclear explosion and consideringt the amount of metal to hold up such a structure, and the area of the world chosen (e.g. Singapore), that's how you get 2 billion people killed....

So if you don't like the numbers...Do the friggin math!!

Okay, your first mistake is assuming a sphere. Why? As I've said REPEATEDLY we're talking about something the width of a sheet of paper. So, let us examin the mathematics for terminal velocity of paper, shall we?

Terminal velocity, the point where air drag counters the force of gravity and velocity becomes a constant is achieved when:

V(t)=sqrt[2mg/pS(ref)C(d)]

where

V(t)=terminal velocity
m=mass (Kg)
g=force of gravity (9.81m/sec(sqrd))
p=air density (kg/m3)
V=velocity (m/s)
S(ref)=reference area (m(sqrd))
C(d)=coeffiecient of drag

Lets use a penny, that's close to the same mass as your example. Actually a penny is 2.5 grams, has a diameter of 19mm, so it's maximum surface area is 0.00028m(sqrd)witha coeffiecient of drag no greater than 1.17. Now, the atmospheric density decreases as you increase height, but lets take the measurement of the density at sea level as the increasing drag will continue slowing the penny as it falls throughout it's drop path. Air density at sea level is 1.225 kg/m(cubed).

Doing some math shows that the maximum terminal velocity of a penny is 40km/hour (11m/sec). Seems to be a bit less than 100 miles per hour.

The kinetic discharge of a penny striking at 40 km per hour is, as you pointed out:

KE = 1/2 m V(sqrd)

So the Kinetic discharge is 151 gram meters/sec(sqrd)
or
0.3 Joules. For comparison, a BB gun hits at about 20 Joules.

Well, we did some friggin math. Have I mentioned I got my undergrad in applied mathematics with an aerospace discipline?

 

[Alchemist29]

The other aspect that doesn't quite jive with the apocolyptic visions of 2 billion deaths is where is where is this deadly projectile coming from?
The ribbon? nope, the upper part would burn up and the lower part would fall to the ocean (although we could consider a tsunami if you want to)
The climber? I would like to think that redundant (parachute) safety systems would be involved.
The upper anchor? It would also have safety systems as well as emergency rockets to keep it in orbit while a recue operation is sent.

So at worst we have a tsunami, but calculating that is beyond my mathematical ability.

 

[wkwillis]

The easiest way to drop steel from orbit is to foam it and dump it out the back end of a linear accelerator. Then it falls down through the atmosphere at a terminal velocity of twenty miles an hour and floats around on the ocean till you pick it up and take it away to be melted and rolled. This also works for platinum group metals and gold.
What is the terminal velocity of a one pound beach ball?
Hey, don't flame each other, chill.