Why aren't we shooting supplies into space?

yea the accelerator would be better but like you said drilling holes into a mountain isn't gonna be fun. and your not thinking of this, America doesn't have too many tall mountains. so this project would have to be a joint project but there is too much global tension for this to be accomplished right now.

How about through the Earths elecrotmagnetic grid, will be used for the propulsion system through a long flexible tube, probably more of non-earthly material.

Los Alamos talked about a vacume system I believe or propulsion.

Sounds like they took out their OLD PLANS, and stuck in some NASA b.s to silence the crowd, the nano-technology they had previously spoke of talked about it being ready in 2025.

It sounds like they doctored up a more recent format to fit COMMOM SOCIETY BELIEF SYSTEM.

Originally posted by N. Tesla
space elevators are impractical and impossible. there is no metal currently known to man that something like that can be built. watch the 3 part series called the 2057: city, 2057: health, and 2057 : world. the 2057: world part talks about space elevators but at this point they are still an impossibility.

Thanks for the reference to the series thing, but I know something about this technology.

You are correct in that, at present, a space elevator is impossible. However just over 100 years ago it was impossible to fly in a heavier than air machine, just over 60 years ago it was impossible to fly faster than the speed of sound, just over 50 years ago it was impossible to fly outside earths atmosphere, just under 40 years ago, it was impossible to land a man on the moon...are you seeing the pattern?

A space tether/elevator will not always be impossible, and when it becomes possible (based on materials strength and economics to build it) it will be the most practical method possible for escaping earths gravity...at least until someone develops a gravity drive system.

reply to post by ngchunter

was outliving his usefulness.

That would make no sense.
They ended up with it half built and it turned to junk.
Iraq is not that stupid and if they wanted him dead they would have done it in Iraq.
They could kill anyone they want, in their own country and get away with it.
And I guess Israel is not going to blow up nuclear plants in Iran, either.

I would like to propose a hybrid solution.
Indeed the amount of Gs resulting from using the currently available explosive compound can be quite high which would make designing circuitry and avionics of the payload to be delivered into orbit quite challenging, not to mention the types of advanced materials required to withstand the after effect of firing a larger scale projectile.
Also for the payload to remain in obit, to sustainably escape or counter the earth's gravitational pull by means of centripetal forces the payload will need to attain very high speeds while in outer space (initially as speed decay is not so significant as there is no much drag out there).
Attaining very high speeds while in the muzzle or even after leaving the muzzle but still in low altitude can lead to challenging side effects. The sonic boom for one while the large payload is still traveling in the confines of the muzzle. Low altitude means, higher pressure (more air molecules in a given volume) which translates to higher drag probabilities.
In a nutshell the challenges are (this is just a subset)
1)High Gs – effect on payloads circuitry (we are not sending dumb shells up there)
2)High pressure generated from initial blast – effect on payload and muzzle
3) Supersonic(even hypersonic) side effects (especially at low altitudes) – sonic boom
4) Significant recoil


Perhaps a solution may involve derivatives of the following.
1)A catapult system consisting of a very long rail, cables, piston driven by steam, slow acceleration, maintain payload friendly Gs. More like the catapults used on the aircraft carriers, but in this case, a larger more powerful, and faster one with a much longer run. The rail may be positioned at some comfortable incline perhaps along a mountain sloop.
2)Payload to consist of stage 2 propellant – this will kick in when projectile is attained some predefined altitude. - The aim of this burn in to quickly increase altitude then speed with the aim of attaining speeds required for gravitational pull escape and finally get projectile to space.

-Allan

reply to post by Anonymous ATS


i could actually see that working but the problem is how big would this catapult need to be?

and as for the recoil of the cannon, the cannon could be placed on springs or held in place by low tension wires.

Originally posted by N. Tesla
hmm a giant tube sticking out of the Earth, or a cable hanging from space. well the tether from space just seems so... dumb

.... snip.....

what is this tube or tether going to be attached to in space?

You didn't read the info i provided you, did you? It "attaches" to centrifugal force.

what i meant was that how would it be attached to the space station. or are you saying that the elevator would only be used to shoot things into orbit? the way i see it is that the elevator would still have to attached to the space station so that it could transport astronauts and supplies.

and i still don't see something of that magnitude being built and staying there.

Originally posted by jmdewey60
reply to post by ngchunter

 

was outliving his usefulness.

That would make no sense.
They ended up with it half built and it turned to junk.
Iraq is not that stupid and if they wanted him dead they would have done it in Iraq.
They could kill anyone they want, in their own country and get away with it.
And I guess Israel is not going to blow up nuclear plants in Iran, either.

Who was Iraq fighting at the time? Iran. I didn't say the Iraq possibility was particularly likely, I said it was proposed. Unless they had reason to believe he was about to take his knowledge elsewhere I doubt they would have offed him. When Israel takes out the Iranian nuclear facilities it will be because they refused to halt their ambitions at the demand of the rest of the world, but Israel was not the most immediate target for Iraq at that time, Iran was.

[edit on 16-7-2008 by ngchunter]

reply to post by N. Tesla


Synchronous orbit.

You have to change your thinking. If there is a long tether, with one end in space and the other on earth, then you have centrifugal force causing one end to lock into orbit. Put the ISS in synchronous orbit. The key is not attaching the tether to the ISS, as you would then transfer the energy of the centrifugal force and gravitational pull to the ISS. Unless you can adjust the stabilizers to keep it in a stable orbit.

Edit to add:

I found some info for you on space tethers. Please read it. The interaction of gravity, centrifugal force, and momentum really provides some exciting possibilities:

en.wikipedia.org...

A couple of highlights:

Skyhooks
Main article: Skyhook (structure)
A tidal stabilized tether is called a "skyhook" since it appears to be "hooked onto the sky". This term was introduced by the Italian scientist Giuseppe Colombo. Skyhooks rotate precisely once per orbit and hence are always oriented the same way to the parent body.

Some are called "hypersonic skyhooks" because the tip nearest the earth travels about Mach-12 to 16 in typical designs. Longer tethers would travel more slowly. At the limit of zero ground speed, it would be re-classified as a space elevator or beanstalk.

An aircraft or sub-orbital vehicle transports cargo to one end of the skyhook.

Skyhook designs typically require climbers to transport the cargo to the other end (like a beanstalk).

Robert Raymond Boyd and Dimitri David Thomas (with Lockheed Martin Corporation) patented the Skyhook idea in 2000 in a patent titled "Space elevator"[1].

The company Tethers Unlimited Inc (founded by Dr. Robert Forward and Dr. Robert P. Hoyt) has called this approach "Tether Launch Assist".

and this one:



Momentum exchange tethers
A momentum exchange tether is a high speed rotating tether, spinning so that the tips have a significant speed (~1-3 km/s).

The maximum speed is limited by stress tolerances of the tether but this can be greatly increased if it is of thicker cross-section in the middle and tapers and is lighter, thinner at the tips.

A spacecraft could rendezvous with one end of the tether, latch to it, and be accelerated by the tether's rotation. The tether and spacecraft would then separate at a later point when the spacecraft's velocity has been changed by the rotovator.

This is not free. The tether's momentum and angular momentum is changed, and this costs energy that must be recouped. The idea is that the recharge could be done with some form of energy (for instance solar panels generating current for electromagnetic propulsion) that is far cheaper than multi-stage-rocket fuel.

Rotovators can also be used to slow down incoming spacecraft, thus increasing the rotovator's momentum. If the average momentum gained from inward traffic equals that imparted to outward traffic, there is no net energy cost, and thus nothing to recoup.



basically are what i referred to earlier. Read the whole article. It is very interesting. Perhaps Matyas will explain it better for us if he comes by here.




[edit on 16-7-2008 by bigfatfurrytexan]

reply to post by ngchunter

Israel was not the most immediate target for Iraq at that time, Iran was.

Almost everything I know about it comes from tv, so they may have had their own slant.
Israel was probably very curious about what he was doing, in an open sort of way.
Iran would have been just as curious, but did not leave any evidence of how they were satisfying their curiosity.
Israel made a better story, for tv.
I do not know, and you could be right.

i will not even try to pretend that i understand the complex physics involved in this but i think i get the general idea. i see how the skyhook works and if it works as described then it could be very useful for launching things into deep space as well(attaching a space shuttle to it and using the skyhook momentum to launch itself farther.).

but as i understand 50miles of the surface counts as space(correct me if I'm wrong) how do you imagine a structure of that size being built?

reply to post by N. Tesla


Have you looked at the STS-75 video? It is known as "The Tether Incident".



Everyone has seen it, and likes to talk about the "critters" that are seen floating around. But, just as interesting, is the tether, its length, and what happened to it.

From NASA

At approximately 7:30pm CST, after TSS-1R had deployed 19.7km of tether and had almost reached full deployment, the tether broke.

I will mention that the tether (at about 20 km long) broke only because it was fried by electrical arcing. It was not the physical stress.

10miles and 50miles is a big difference. and you still need something to build the tether out of.

Originally posted by N. Tesla
but as i understand 50miles of the surface counts as space(correct me if I'm wrong) how do you imagine a structure of that size being built?

If you find a 50 mile structure hard to imagine, I hate to have to tell you that a space elevator or tether would need to be 22,000 miles high. It needs to terminate in geosynchronous orbit (22.something, 000 miles).

It needs to be this high because this is the distance at which an orbiting body's velocity matches the rotational velocity of the earths surface. And you can see how important it would be for the top of the elevator to remain in the same position directly above the base of the elevator at all times...right?

It won't be as dificult as it seems however. Most if it will be a non-rigid cable-like material constructed of bukminsterfullerenes, carbon nano-tubes, or some other exotic, yet-to-be developed material.

Now...this whole geo-synchronous thing can be ignored if you build an actual tower-like structure (imagine a rerally really big Empire State buiding, or CN the tower if you're Canadian), but believe me.....building a rigid tower-like structure 100 miles tall is way, way, way, beyond the technology and materials needed to deploy a tethered elevator system.

Soething else you might not be seeing. When I say elevator. I don't mean a compartment inside a tall tube being raised and lowered by cable and pulleys. I'm talking about a self powered compartment that climbs up the tether under its own power using gears, or magnetic attraction/repulsion technology, or other more complicated means.

Hope this helps.

i meant 50miles off the ground. and i figured the elevator would be pushed up with rockets or a rail gun sort of thing.

reply to post by N. Tesla


sigh...didn't i already provide info on tether building material? Carbon Nanotubes.

Now, i am not saying that there is a 50 mile tether out there. If there was, we would be using it. But we are getting VERY close (and not using nanotubes yet, either):

YES2 Team Claims Space Tether Record

“By looking at the data from the tether deployment speed sensors, we are able to determine how much of the tether was unwound and how quickly it deployed,” said Michiel Kruijff, lead system engineer for Delta-Utec. “We can tell that the deployment was accelerating in the later stages, rather than slowing down as we first believed. We have also found that the tether deployed to a minimum of 29.5 km, or more likely to its full length of 31.7 km, at high speed.”

I'm not saying anything about the tethers. I'm saying that there is not enough of the material to build it. and how will the elevator get back to the ground? I guess rockets will slow it but then how much fuel will this thing be using or what kind of braking system will there be. and i still don't think that they will be able to get that much tether into space. maybe in 50 years but not any sooner.

reply to post by N. Tesla


i would recommend you begin researching this so that you can abate any gaps in your understanding. What do you mean there is not enough material to build it? They aren't building it from He3. Carbon nanotubes can be grown en masse, and current Raman measurements show that we can grown about 1.3 to 1.6 nm per second. I don't think production is going to be a problem.

Search terms like "Tether". There is a wonderful link i provided you above about tethers.

I would also recommend you start digging into materials science. Everyday that goes by see's about 10 years worth of advancement. Nowhere does Moore's Law seem more apparent than in nanotech.

It will do you no good to sit on a forum, get spoon fed information, and guess as to how it may or may not work. You need to roll up your sleeves and go find your answers at some point.

I will tell you that you don't grow a single strand of carbon nanotube. I suppose it can be done eventually (we aren't there yet).

here is an article discussing one company's attempt in 2006:

space.newscientist.com...

To make the cable, researchers sandwiched three carbon-fibre composite strings between four sheets of fibreglass tape, creating a mile-long cable about 5 centimetres wide and no thicker than about six sheets of paper.

"For this one, the real critical test was making a string strong enough," says Michael Laine, president of LiftPort. "We made a cable that was stationed by the balloons at a mile high for 6 hours…it was rock solid."

A platform linking the balloons and the tether was successfully launched and held in place during the test. LiftPort calls the platform HALE, High Altitude Long Endurance, and plans to market it for aerial observation and communication purposes.

[edit on 16-7-2008 by bigfatfurrytexan]

not only are carbon nanotubes still being tested but they are extremely expensive. at 50-100$ a gram how much would it cost to make a mile? how much would it cost to make something like that. and i still dont think something that big could just be shot into space. and it still needs a counterweight at the other end.

I'm not saying that space elevators are always going to impossible. but for the next 50 years it is. a cannon is doable now and would cost so much less to make .