Space elevator ? How can it work?

LURCH

I have no doubt that a strong enough material will be developed. However, for a space elevator to be possible around the earth, we would have to first eliminate all of the sattelites in low earth orbit. There is no point on the equator over which these sattelites will not eventually pass. When they do, they will strike the elevator shaft at about 15,000 miles per hour. If we hadn't done sattelites first, a space elevator would be possible. But as far as I have seen, no one has ever addressed this situation adequately. And, as the situation currently stands, a space elevator is simply not possible.

DaveC426913

This is an area of lively study. The cable is heap big flexible and can be maneuvered. Simulations have been done that show the cable can be moved out of the way of any satellites. (Don't assume that it is as simplistic as I describe. There's a lot more to it.)

dr dodge

IMHO, It'll never happen.
for gosh sakes, we can't even agree on putting up wind towers without some group pitching a hissy fit about "issues"
I have real problems with all current nano tech. there ia a lot of it going on, but very little health and safety understanding. nano fibers pass right thru most living tissue. now, string a massive amount of it together, hang it in the air, subject it to intense light, heat, wind and radiation and tell me it won't sluff nano particles into the air.
another thing that no one has addressed is the electrical charge that it would pick up. anyone remember the shuttle experiment with dragging the cable?
http://istp.gsfc.nasa.gov/earthmag/wtether.htm
from what I heard, they almost blew the whole electrical system due to the massive emf ramp up
think on big long carbon resistor.
how many golfers and fishermen get hit by lightening thru their carbon graphite accessories?
that thing would probably drag lightening in on an unbelievable scale.
spend the $$$ on the aircraft industry, with their proven track record of slow, but positively forward advancement
best bang for the buck and absolutely the safest

dr

DaveC426913

Other than the VentureStar, what is the aircraft industry's solution to achieving orbit?

The industry's delta vee is shy by a factor of 10. (2,500mph vs. 25,000mph)

Space shuttle doesn't count; it's just a rocket.

dr dodge

all I was saying is that some technology that generally works well, exists in the aircraft/aerospace industry
its a lot closer than a 200 mile vertical cable, built out out of untried material by a technology that we don't have. (I like the nanobot idea best)

personally, I think its gonna be real hard to beat the rockets for quite some time

dr

DaveC426913

Rockets are rapidly reaching a point of diminishing returns. You don't see any more Saturns going up do you?

dr dodge

the rockets weren't/aren't good for heavy lift, and thats where the real need is.
but for most mid to small stuff they will probably be used for many years

dr

chayced

I don't really like the idea of a space elevator. Lots of technical challenges, lots of cost, in the end you have an untested expensive system that you put into some sort of geosynchronous orbit, and if it crashes down after a week you have nothing to show for it.

Why not focus on a space gun? We have the technology to launch projectiles into orbit, and having the majority of the propulsion system on the ground where it is easily repairable is a definite benefit. I guess the idea is just not trendy enough to be researched.

LURCH

Not true, not true! You have a huge, trench-shaped impact crater that goes almost all the way around the equator!!

Mech_Engineer

Like in the book Green Mars!

mgb_phys

It is researched.
the research goes something like:
V² = U² + 2as

Assume a 100m long barrel, and an escape velocity v of 11km/s
a = V²/2s = 11,000²/200 = 600,000m/s²
a = 62,000g
There is also the small matter of air resistance when the payload leaves the (presumably evacuated) barrel and enters the ground level atmosphere at > Mach30.

mugaliens

Agreed.

Non-sequitor. While it's true that rockets are providing diminishing returns, that has nothing to do with the lack of current viability in the tether arena. Rockets are here and now. Tethers are several decades away, if not a century.

LURCH

Please tell me they don't propose a space elevator on Mars?!

mgb_phys

It has certain advanatges, you don't have to wait for the butterflies

chayced

At this point putting a space elevator on mars is the equivilent to putting a Starbucks there. When it does become possible it will probably be ancient technology.

dr dodge

ok, I have been thinking about this (I know, VERY dangerous)

Wouldn't surface tension of the gases of the earths atmosphere follow the cable higher up the cable. That could potentially cause odd plasma reactions when it got to space. transmitting power up it would require it to either be 2 cables next to each other, or some sort of induction/coax kind of deal. and it would have to be like trying to push massive megawatts thru a tera-ohm resistor.
OK, we make the cable, how are we supposed to get it to the earth. upper atmosphere winds would drag it around all over while we are trying to get it to the ground. think about lowering a piece of fishing line off your roof to touch a 1/4 inch square a basketball on the ground. even on a zero wind day, you'd have to send out so much extra cable just to finally get a grip on it to drag it back to the point of attachment. at the point in time that we were just ready to attach it to the earth, the static on that thing would be...well
How much slack would it need to allow for the wobble of the earth? The pulling on the cable would try to pull the satelite out of orbit on the way up, and shove it out on the way down. you'd need a spool of cable the size of the moon, and a tensioner the size of rhode island to keep the cable tension correct.
IMHO, the following formula applies:

elevator idea+(many$$$$$$$$)=stick and deceased equestrian

dr

Gfellow

"Space Elevator" has been in my Google Alert for quite some years now, and I have noticed a tenfold increase in the chatter on the subject. It would appear that the concept is rapidly becoming part of the collective consciousness.
It is notable that the Japanese are looking to spend 8 billion on such a project, and while that might seem an insignificant fraction of the final cost, it makes for interesting seed money.

Whether building a space elevator is feasible can be an arguable subject, but IMHO there is little doubt that someone will try. The rewards are just too big to ignore. I won't go into the mass/lift ratio advantage here, but considering the relatively small resource outlay, the political stature and military advantage that a space elevator will afford, will ultimately be too tempting for any number of powerful nations.

As a real-estate speculator, my focus of interest is where it might be located. For logistical, physical and political reasons, my bet is the island nation state of Nauru. The island is on the equator, minimum security issues, harbor installations, commercial runway, tarmacked road rings the island.

The only other places available on, or near the equator are either politically insecure, or have no infrastructure.