Is a space elevator a real possibility?

[Allan]

Having speculated a Space Elevator in my plot I've had to do a lot of exploration of the web to acquaint myself with the needs and pitfalls. I've rewritten those 3-4 chapters at least 10 times. In fact the physics behind the Elevator is what brought me here to this site.

The carbon nono tachnology seems to be the prevalent element for the tether due its its incredible strenth and flexability.

The additional legnth beyond the 22,300 mile ribbon would serve as a counter weight and allow for vehicles to the flung into space without fuel (naturally something will be needed to adjust course heading). Imagine the possabilites of such a sling! Nuclear waste hauled into space and flung toward the Sun! Space craft being give a healthy heave-ho on their way to Mars or more! Satillites being lifted into oribt and flung in the direction they need to so before they unfurl their solar sails and carry on endlessly (potentially, of course).

The elevator itself, if people weren't present, could travel insanely fast and without air. If people were on board it would not be unreasonable for the compartment to travel 33 feet per second (reasonably based on the actual elevator in the Dubai tower) without the need for people to be restrained. A leisurely trip into orbit????

The cost will be steep no doubt, but the elevator will grow to be a cost effective and an ecologically sensible way for man to take his first step into the void. Once established satellites can be easily setup in space and deployed in stages to make way-point.

This stuff is billiant....Yes I know there are problems to solve. But I'm just a writer...a visonary if you would, and all remarkable "stuff" we take for granted today was once in the realm of imagination until folks like you worked out the kinks.

:thumbup:

The potential of this technology is limitless.

 

[NCC-1701]

No burning up either - once it reaches the atmosphere it will be going roughly at the speed of local winds (geostationary).

But by the time that it gets down to the thicker atmosphere it will be falling so fast that it would most likely start to burn. Maybe some kind of parachute...

 

[tori]

(...) allow for vehicles to the flung into space without fuel (naturally something will be needed to adjust course heading). Imagine the possabilites of such a sling! Nuclear waste hauled into space and flung toward the Sun!

[1] In order to achieve escape velocity, an Earth-based elevator would need to release its cargo at roughly R=53 223 km (46 845 km above the surface). Hm... arright

[2] For a deorbit into the Sun (30 km/s delta-v), it would have to be at least 406 151 km long (from the equator up) ... which means the Moon would get in the way, and I can see that causing a problem or two :lol:

[1]

(G = gravitational constant, M = mass of the planet, T = period of its rotation)
[2]

(v = desired tangential velocity)

t will be falling so fast

Why would it be falling at all? I always imagined it to be rolled down slowly, couple m/s. With a little weight on the lower end to battle the winds and keep it straight it could roll as slow as it wants, without deorbiting as long as the system's center of gravity remains exactly at the GSO altitude.

 

[T.Neo]

Nuclear waste hauled into space and flung toward the Sun!

Waste of time flinging it into the Sun; the Dv to get to it is prohibitively high (and is likely above the abilities of the "sling"). If you want to send your nuclear waste to somewhere in space, perhaps use subterranean storage areas on the Moon.

Nevertheless using an elevator to hoist nuclear waste is an interesting concept, and one probably more reliable than a rocket launch (unless something were to happen to the payload on the tether).

Space craft being give a healthy heave-ho on their way to Mars or more!

I'd love to see the actual extra Dv this would allow...

The cost will be steep no doubt, but the elevator will grow to be a cost effective and an ecologically sensible way for man to take his first step into the void.

Studies would need to be conducted on whether the cable itself poses any threat to the global ionosphere, or magnetosphere for example.

Yes, the elevator cars will be emissions free. But rocket designs such as LH2/LOX have exhausts comprised of almost wholly water which does not contribute to atmospheric carbon- although it does, unfortunately, lead to ozone depletion. Perhaps they could, conversely, be used to replenish ozone in the upper atmosphere. (such a program was even proposed for the Energia program).

The problems of micrometeor/debris erosion, atmospheric "short circuiting", radiation exposure, political vulnerability and downright unflexibility of an elevator leads me to believe that conventional surface-launched spacecraft are altogether better.

There are also [ame="http://en.wikipedia.org/wiki/Space_tether"]space tethers[/ame] for slinging payloads, if you wish.

And perhaps rockets could be used to repair the ozone layer, too. AFAIK there was a Russian proposal to do so with the Energia rocket, pretty crazy stuff...

 

[Linguofreak]

The elevator itself, if people weren't present, could travel insanely fast and without air. If people were on board it would not be unreasonable for the compartment to travel 33 feet per second (reasonably based on the actual elevator in the Dubai tower) without the need for people to be restrained. A leisurely trip into orbit????

It's not speed that would be limited by having people aboard, but acceleration (and even then your propulsion system would probably be more of a limit than if you were carrying people). 33 ft/s, by the way, while fast for a building elevator, is slow for anything else (it's about 25 mph), and glacial for a space elevator. You're basically taking a railroad and standing it on end. You'd want at least several hundred miles per hour. (At 300 mph the trip would take 3 days).

 

[Adelanthal]

At 33 ft/sec, you're looking at roughly 10 days to reach GEO.... better be one NICE elevator car...

 

[RisingFury]

Having speculated a Space Elevator in my plot I've had to do a lot of exploration of the web to acquaint myself with the needs and pitfalls. I've rewritten those 3-4 chapters at least 10 times. In fact the physics behind the Elevator is what brought me here to this site.

Rewrite No. 11 coming up... :lol:
(If you don't mind a joke at your expense :thumbup

Nuclear waste hauled into space and flung toward the Sun!

You're dreaming... Change in velocity required is 30 km/s. Though just ejecting nuclear waste away from Earth, into an orbit that won't intersect it, is a good idea.

The elevator itself, if people weren't present, could travel insanely fast and without air. If people were on board it would not be unreasonable for the compartment to travel 33 feet per second (reasonably based on the actual elevator in the Dubai tower) without the need for people to be restrained. A leisurely trip into orbit????

At 10 m/s you're talking a hell of a long rid. More of a ~10 day cruise to geosynchronous altitude. Besides, velocity doesn't really matter if you're traveling in airless environment. Acceleration, change in velocity over time, does. The jolt you feel in the elevator is not the result of velocity.

Now, velocity would definitely be limited on a space elevator, but not because of passengers. The faster you wanna go against the force of gravity, the more power you need (Power defined as change of energy over time) and if you managed to get enough power, there are structural limits to worry about.

The power needed just to go against the force of gravity (not taking into account friction and air resistance) can be expressed this way:

P = F * v (the general equation)
F = m*M*G/r^2 (force of gravity)
P = m*M*G*v/r^2

So if you imagine a 10 metric ton car, traveling at 1 000 m/s. That would still give you a time of about 10 hours to reach geostationary altitude, but just as you left Earth's atmosphere (~100 km altitude), the power requirement would be 10^8 W! The coal fire power plant in my town produces 7 * 10^8 W at it's peak capacity.

Now... that's assuming all of the power goes into propulsion. In reality, there are losses. Large electric motors, beyond 10 kW are just under 100% efficient, so they're not the problem, but you need to get the power to the climbing cart somehow. You could build a power line into the line the elevator uses to climb, but that's thousands of kilometers worth of resistance. A good proposal is to fire a lases onto the car's solar panels. We can probably assume around 30% efficiency in the conversion - solar panels aren't 100% efficient, laser scatters through the atmosphere, creation of a laser beam isn't 100% efficient either,...

So this quickly shows that if you want to run a space elevator, you're going to need a large, dedicated power plant as well...

The cost will be steep no doubt, but the elevator will grow to be a cost effective and an ecologically sensible way for man to take his first step into the void. Once established satellites can be easily setup in space and deployed in stages to make way-point.

I have my doubts that a space elevator could pay for itself. That would probably hold if we don't find a cheaper way to orbit with rockets, but if you take into account the better technology and the resources needed to build an elevator... I must say I doubt it would pay off.

I'd say the more interesting thing to look at with a space elevator is it's safety... if a rocket blows, it can go off like a miniature nuke...


It certainly is an interesting concept and fun to think about.

Good luck with your writing

 

[Allan]

Or 1 day to reach low orbit (540 miles) where gravity is less a factor toward faster acceleration. At that ppoint (if feasabile) you could strap in to haul $$$ for the remaining 21,760 miles. There is no rush.

I've read of proposals to use multiple elevators to offer counter weight for the acenscion as the alternatate elevator lowers. It would also speed the frequency of delivery to orbit and stabalize the line. Not sure how speedy that would be...there is a little rush

Nuclear waste. Even if the prospect of propelling it directly toward the sun is impractical (or dangerous) its still worthwhile to use the Elevator to transport it. Perhaps a "slow" moving barge that sits in space being robotically filled with waste before being given a substantial nudge?

I don't have all the answers but I do find the possabilites intriguing.

---------- Post added at 09:27 PM ---------- Previous post was at 09:18 PM ----------

Rewrite No. 11 coming up... :lol:
(If you don't mind a joke at your expense :thumbup

No worries

Now... that's assuming all of the power goes into propulsion. In reality, there are losses. Large electric motors, beyond 10 kW are just under 100% efficient, so they're not the problem, but you need to get the power to the climbing cart somehow. You could build a power line into the line the elevator uses to climb, but that's thousands of kilometers worth of resistance. A good proposal is to fire a lases onto the car's solar panels. We can probably assume around 30% efficiency in the conversion - solar panels aren't 100% efficient, laser scatters through the atmosphere, creation of a laser beam isn't 100% efficient either,...

I'd say the more interesting thing to look at with a space elevator is it's safety... if a rocket blows, it can go off like a miniature nuke...

Electricity is the key. Not rockets, no fuel.

It certainly is an interesting concept and fun to think about.

Good luck with your writing

Appreciated. I knew even trying to talk in this site I would be at a technical disadvantage but the topic is so compelling. My book uses potential technology as a vehicle for my storyline about mankind. The story isn't centered on technology but at the same time I'd like to appeal to the imagination of SciFi readers!

I do appreciate the input and will seldom take offense. If a Space elevator didn't have serious hurdles it would already be here.

 

[Ghostrider]

At 33 ft/sec, you're looking at roughly 10 days to reach GEO.... better be one NICE elevator car...

Why not, back in the old days when trains and ships took days to reach their destination, they used to make some comfy arrangements. Why not travel in style...

 

[tori]

The first couple years (decades?) it'll be hauling cargo and getting man-rated anyway, so they'll have plenty of time to test and improve it.

 

[Allan]

If/when this mode of transportation becomes commonplace luxury will determine cost more so than speed. The costs will be absorbed, my supposition, by companies wanting to get their materials/people/equipment into orbit less expensively (and more safely) than a rocket.

There could be several elevators that share the tether, one of which could be a pseudo hotel for the 24 hour ascent. Just a possability to consider.

 

[statickid]

but well built rockets can be very reliable!

 

[Ark]

Honestly, the massive up front cost required before any possibility of a profit makes this pretty unlikely in the near future.

 

[fireballs619]

I personally like the concept of a space fountain better .
[ame="http://en.wikipedia.org/wiki/Space_fountain"]Space fountain - Wikipedia, the free encyclopedia[/ame]

 

[Hielor]

Or 1 day to reach low orbit (540 miles) where gravity is less a factor toward faster acceleration. At that ppoint (if feasabile) you could strap in to haul $$$ for the remaining 21,760 miles. There is no rush.

Keep in mind that even if you ride the elevator up to the "low orbit" area, you won't be in orbit. You'd still need quite a lot of horizontal velocity in order to get to a station in LEO from an elevator..

 

[RisingFury]

I personally like the concept of a space fountain better .
Space fountain - Wikipedia, the free encyclopedia

An elegant concept... until there's a problem with the power supply

 

[Richy]

Was [ame="http://orbithangar.com/searchid.php?ID=1891"]Kulch's Space Elevator Addon[/ame] ever mentioned in this thead?

An awesom addon, and nice to experiment and get a feel, what it means, to ride an elevator into space.

 

[Orbinaut Pete]

For any interested & able to attend, a Space Elevator Conference by Dr. Bryan Laubscher will take place from August 13-15 at the Microsoft Conference Center in Redmond, Washington, USA. The conference is free & open to the public (no registration required).

Space Travel: "2010 Space Elevator Conference".

 

[Keatah]

This thread had already been dead for 5 months before your dredged it up...

What is the point of the board archiving threads if folks complain about an old topic being revived? This seems to be a common phenomena both here and elsewhere, getting more intense with the increasing intelligence of the user population.

What if the topic is new to someone else? Someone else might have something to contribute after contemplating topic while on sabbatical..? Maybe we need a forum specifically for old threads? Well I liked this thread enough to subscribe to it!

Anyways, about the space elevator thing. There's a *LOT* of detail that needs to be worked out, far too numerous to mention in lowly messageboard posting. Enough that there could be papers and dissertations written on the subject for years to come.

To me, at first glance, a space elevator is a romantic thing. Nothing could be more serene then sailing out to a lily pad shaped island on a musical sailboat and stepping into a banquet hall sized glass room that rises to the heavens and beyond in total silence, with a view to break the heart of the most hardened poet. Drifting through happy clouds and boundless rainbows. Especially with a sunset and moonrise thrown in! Flower shaped dirigibles wishing you well on your ethereal ascent..

Yeh I could go for that!