Author Topic: Space Elevator Development  (Read 23778 times)

Offline markbulmer

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Space Elevator Development
« on: 01/05/2017 10:49 pm »
Hey guys,

New to this forum. Just was researching some interesting things regarding space elevators: https://en.wikipedia.org/wiki/Space_elevator

It seems like the cost of launching to space is a lot and having a space elevator would reduce the cost of putting something into space for ~$20,000/lb to ~$200 a lb. Wouldn't having this kind of cost advantage to launches be worth developing an elevator-style launch system ?
« Last Edit: 01/06/2017 12:25 am by Chris Bergin »

Offline nacnud

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Re: Space Elevator Development for Space-X ?
« Reply #1 on: 01/05/2017 11:04 pm »
Yes space elevators could be cheaper, but they are basically impossible to build.

Offline Robotbeat

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Re: Space Elevator Development for Space-X ?
« Reply #2 on: 01/05/2017 11:10 pm »
Funny thing is that if you believe SpaceX's numbers, space elevators aren't even cheaper even if we had good enough materials. ITS tanker is supposed to achieve a tenth that cost, less than $20/lb to LEO.

If you got really good at chemical rockets like SpaceX proposes, it gives basically every alt-launch concept a run for its money.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline AncientU

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Re: Space Elevator Development for Space-X ?
« Reply #3 on: 01/05/2017 11:17 pm »
Funny thing is that if you believe SpaceX's numbers, space elevators aren't even cheaper even if we had good enough materials. ITS tanker is supposed to achieve a tenth that cost, less than $20/lb to LEO.

If you got really good at chemical rockets like SpaceX proposes, it gives basically every alt-launch concept a run for its money.

Even undercuts the cost of ISRU propellant production from the Moon... 
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline russianhalo117

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Re: Space Elevator Development for Space-X ?
« Reply #4 on: 01/05/2017 11:33 pm »
Yes space elevators could be cheaper, but they are basically impossible to build.
It would function the same as a deorbit tether for a satellite if long enough.

Offline Chris Bergin

Re: Space Elevator Development
« Reply #5 on: 01/06/2017 12:27 am »
Welcome Mark. Moved it out of general and made it a more specific title (everything's not about SpaceX ;))

Space Elevators are very 2005.
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Offline colbourne

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Re: Space Elevator Development
« Reply #6 on: 01/06/2017 01:03 am »
Space elevators would be very slow. Probably only able to have one shuttle on the cable at once. Any material we can dream of means that they will be very heavy and this all has to be launched in to space before it can be used.
On Earth I see no future for them. On other smaller planets and moons they could be of use.

I do see a potential for rotating tethers (bolo) to pick up small craft and move them to different orbits.

Offline Robotbeat

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Re: Space Elevator Development
« Reply #7 on: 01/06/2017 03:02 am »
Welcome Mark. Moved it out of general and made it a more specific title (everything's not about SpaceX ;))

Space Elevators are very 2005.
Yeah, this is 2017. The only elevators we care about is this one that's one tangentially related to SpaceX:
http://forum.nasaspaceflight.com/index.php?topic=41017.msg1623401#msg1623401
:D
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline SEI

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Re: Space Elevator Development
« Reply #8 on: 05/28/2018 07:56 am »
Here is a new train of thought to come up
with a theoretical solution to a Space Elevator:



The aim of these brainstorm videos is to visualize
a potential solution to a Space Elevator.

As the videos progress, they build upon the previous videos
refining the content with new research and taking into account
feedback and comments.

Please subscribe and share with anyone you think may be interested
to contribute to this initiative.

Offline A_M_Swallow

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Re: Space Elevator Development
« Reply #9 on: 05/28/2018 12:25 pm »
100 km - are you suggesting a space elevator or just a very tall tower?

Height is relatively easy it is orbital velocity that causes the difficulties. This is why the space elevator cables have their centre of gravity at GEO.

Offline SEI

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Re: Space Elevator Development
« Reply #10 on: 05/29/2018 06:51 am »
the 100 km first stage is just to put pay-loads higher up in the atmosphere.
(this 100 km might actually be lowered as the research progresses)
It then switches to the OPUM (ORBITAL PICK-UP MODULE) stage which act more
as pick up drones. Then to the SPACE DOCK, then to the SUMMIT.

This is still just the general concept, a lot of refinements still to come as the research
progresses

Offline Nibb31

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Re: Space Elevator Development
« Reply #11 on: 05/29/2018 11:35 am »
So you get your payload to 100km altitude with a speed of 0.

Now all you need is an orbital drone equivalent to a fueled Falcon 9 or Ariane to push your payload from 0 to orbital speed (without losing altitude).

How does this make the job any easier?
« Last Edit: 05/29/2018 11:39 am by Nibb31 »

Offline scienceguy

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Re: Space Elevator Development
« Reply #12 on: 05/29/2018 04:43 pm »
It would have more than a speed of 0 because the Earth rotates with the elevator.
e^(pi*i) = -1

Offline A_M_Swallow

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Re: Space Elevator Development
« Reply #13 on: 05/29/2018 05:30 pm »
It would have more than a speed of 0 because the Earth rotates with the elevator.

The top of the tower would move at 1 revolution per day, same as the Earth's surface.

Offline SEI

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Re: Space Elevator Development
« Reply #14 on: 05/29/2018 06:06 pm »
Yes, at the top of the 'FLOATING DOCKS', the OPUM or Orbital Pick-Up Module would have to hook the pay-load from it's orbital speed.
This is I think the hardest challenge to overcome. Having said that, I believe this is less of a challenge than achieving a 100,000km elevator cable.

Here are  a few of the thoughts that I will try and showcase in the next videos:

-the OPUM is separated into 2 with the 'pick-up' device accelerating ahead of the orbital speed and then
slowing down to allow for a certain pick-up time. This is a damper so that when the pay-load is hooked, there
is a dampening of the acceleration.
-A ramp at the FLOATING DOCK level that free-falls the pay-load which then accelerates along
a mag-lev rail. (bearing in mind the atmosphere is thinner and hence there is less air resistance)
-this rail (we're talking a few kilometers long here) has a curve that coincides with the OPUMs trajectory

The idea being that the pay-load is accelerated and the OPUM pick-up head is slowed down along similar trajectories..
When both are aligned which will probably be at a speed in the order of a few thousand kilometers per hour,
they can attach.

There is definitely a challenge there, no doubt.

Offline RonM

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Re: Space Elevator Development
« Reply #15 on: 05/29/2018 07:12 pm »
Yes, at the top of the 'FLOATING DOCKS', the OPUM or Orbital Pick-Up Module would have to hook the pay-load from it's orbital speed.
This is I think the hardest challenge to overcome. Having said that, I believe this is less of a challenge than achieving a 100,000km elevator cable.

Here are  a few of the thoughts that I will try and showcase in the next videos:

-the OPUM is separated into 2 with the 'pick-up' device accelerating ahead of the orbital speed and then
slowing down to allow for a certain pick-up time. This is a damper so that when the pay-load is hooked, there
is a dampening of the acceleration.
-A ramp at the FLOATING DOCK level that free-falls the pay-load which then accelerates along
a mag-lev rail. (bearing in mind the atmosphere is thinner and hence there is less air resistance)
-this rail (we're talking a few kilometers long here) has a curve that coincides with the OPUMs trajectory

The idea being that the pay-load is accelerated and the OPUM pick-up head is slowed down along similar trajectories..
When both are aligned which will probably be at a speed in the order of a few thousand kilometers per hour,
they can attach.

There is definitely a challenge there, no doubt.

How does a 'floating dock' supposed to work, especially at 100 km? That's almost double the record for a high altitude balloon. Unless you have a very clever idea and have done an engineering study with numbers, this is just fantasy.

Offline SEI

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Re: Space Elevator Development
« Reply #16 on: 05/29/2018 07:33 pm »
Yes RonM,

The numbers in this video are only a beginning of the brainstorm and I agree that 100 km is too high.
As I mentioned in my previous post:
'(this 100 km might actually be lowered as the research progresses)'

The idea behind this brainstorm is to adjust and build upon the skeleton I'm providing to hopefully come up with a theoretical solution. this is only video 003. The final video may come to a dead-end or may not look at all like this first draft of a proposed solution.
I call it a ping-pong game. Visuals are very helpful to understand what needs to be done. There are many unknowns and unanswered questions and a degree of fantasy. This is why I'm sharing it, to gather thoughts and come up with a solution.

Since this video was published, I have found out that the record for balloons is 53 km and that the optimal height potentially would be more around the 80 km mark. The floating technology that I'm interested in is the Airlander 50.

Of course, the tech that exists today is just a beginning of what will be required and probably just about every tech that will be needed to pull this off will be pushed to their limits.

Thank you for your comments and please feel free to post numbers and facts so that we can lock down what the realistic height of the FLOATING DOCKS should be.



Offline aceshigh

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Re: Space Elevator Development
« Reply #17 on: 06/05/2018 04:16 am »
it's not brainstorming if it's pure nonsense. Nor it is a space elevator if it's 100km high.

I think you entirely miss the concept of a Space Elevator. I also think you may not have a good clue of the difference between getting to space (and falling down as soon as fuel runs out) and reaching ORBIT.


Orbit is not about altitude. If Earth had no air (like the Moon) and was a perfectly smooth sphere, you could achieve orbit floating 1 meter above the ground. Or even 1 cm.

Orbit is about horizontal velocity. The ground must be getting away from you due to curvature at the same rate you are pulled towards it due to gravity.

Offline SEI

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Re: Space Elevator Development
« Reply #18 on: 06/05/2018 10:24 am »
aceshigh,

To begin with, the height of the FLOATING DOCKS will now be more around the 60-80 km mark. I've added
that as a comment on the video after feedback I've received.
I have failed to mention in video 003 that the FLOATING DOCKS will actually be supported by blimps.
They are meant to be floating balloons, hence the name. I will definitely address that in the new video to make sure there is no confusion, thank you.

The 'space elevator' name is more to stay in line with the existing concept of 'not using rockets' essentially.
I've labelled this a 'multi-stage approach elevator' for now as the ultimate goal is to get to space as efficiently as possible.

and FYI regarding where space begins:
https://www.popsci.com/where-does-space-begin?con=TrueAnthem&dom=tw&lnk=TATW&src=SOC&utm_campaign=&utm_content=5b1278c200bd4700073e9461&utm_medium=&utm_source=


Offline IRobot

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Re: Space Elevator Development
« Reply #19 on: 06/05/2018 01:36 pm »
Sometimes I think we are just feeding Youtube conspiracy theorists/trolls/etc.

Offline Kansan52

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Re: Space Elevator Development
« Reply #20 on: 06/06/2018 11:03 pm »
Relying on memory but it says that each trip on the elevator would be days. That strikes me as very limiting.

Offline A_M_Swallow

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Re: Space Elevator Development
« Reply #21 on: 06/07/2018 03:26 am »
Relying on memory but it says that each trip on the elevator would be days. That strikes me as very limiting.

The elevator is thousands of miles long and you are basically in a car. This limits you to the speeds of fast car. So the journey takes several days.

Offline CameronD

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Re: Space Elevator Development
« Reply #22 on: 06/07/2018 04:28 am »
Relying on memory but it says that each trip on the elevator would be days. That strikes me as very limiting.

The elevator is thousands of miles long and you are basically in a car. This limits you to the speeds of fast car. So the journey takes several days.

So... even if Space Elevator technology was feasible (and it isn't), it'd be a bit like saying:  "Let's not fly from one side of America to the other - that's sooo routine. There's this great new tech called a car.. let's drive instead!!!"  ???

Really?!? Wow!
« Last Edit: 06/07/2018 04:31 am by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline aceshigh

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Re: Space Elevator Development
« Reply #23 on: 06/12/2018 02:09 am »
aceshigh,

To begin with, the height of the FLOATING DOCKS will now be more around the 60-80 km mark. I've added
that as a comment on the video after feedback I've received.
I have failed to mention in video 003 that the FLOATING DOCKS will actually be supported by blimps.
They are meant to be floating balloons, hence the name. I will definitely address that in the new video to make sure there is no confusion, thank you.

The 'space elevator' name is more to stay in line with the existing concept of 'not using rockets' essentially.
I've labelled this a 'multi-stage approach elevator' for now as the ultimate goal is to get to space as efficiently as possible.

and FYI regarding where space begins:
https://www.popsci.com/where-does-space-begin?con=TrueAnthem&dom=tw&lnk=TATW&src=SOC&utm_campaign=&utm_content=5b1278c200bd4700073e9461&utm_medium=&utm_source=


I know where space begins. The question is if you know the difference between space and orbit.

Tell me... what happens if you go up and reach space at an altitude of 300 km at a speed of 5000 km/h and turn off your engines?

Offline colbourne

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Re: Space Elevator Development
« Reply #24 on: 06/13/2018 03:32 am »
If you combine a high altitude base, with an orbital "bolo" type rotating elevator there is potential possibilities of putting something into a high orbit with minimal energy expenditure.

I see no future of the standard bean stalk space elevator on Earth because it is too slow , has too little mass transfer capability and requires the use of unobtainium to be feasible. The mass of the elevator with current materials is so high, all of which needs to be launched with rockets, that it makes no sense.

If we do find an indestructible material so a light weight elevator is possible, there may be potential.

Offline aceshigh

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Re: Space Elevator Development
« Reply #25 on: 06/13/2018 03:52 am »
I see no future of the standard bean stalk space elevator on Earth because it is too slow

for passengers, yes. For bulk cargo? No.

Quote
has too little mass transfer capability

source? 5 store tall elevator... several of them per cable... it all depends on the thickness of the cable, which in theory can be expanded by robot weavers going up and down the cables and adding new threads...

Quote
and requires the use of unobtainium to be feasible.

or just a breakthrough in carbon nanotubes or graphene?

Quote
The mass of the elevator with current materials is so high, all of which needs to be launched with rockets, that it makes no sense.

needs to be launched with rockets?

Offline hkultala

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Re: Space Elevator Development
« Reply #26 on: 06/13/2018 06:16 am »

has too little mass transfer capability

source? 5 store tall elevator... several of them per cable... it all depends on the thickness of the cable, which in theory can be expanded by robot weavers going up and down the cables and adding new threads...

Not very easy ;)

And, always when anything is lifted from the ground to the terminal station, the system loses angular velocity. (which it cannot afford to lose). Need to have (very high isp) thrusters in the terminal station to offset this.

Quote
Quote
and requires the use of unobtainium to be feasible.

or just a breakthrough in carbon nanotubes or graphene?

Mass-manufacturing these in the required scale can be considered unobtainium.

Quote
Quote
The mass of the elevator with current materials is so high, all of which needs to be launched with rockets, that it makes no sense.

needs to be launched with rockets?

It cannot be built ground-up like tower. Most of it has to be built from from up to down. So most of the mass has to be first lifted to GEO.

« Last Edit: 06/13/2018 06:17 am by hkultala »

Offline colbourne

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Re: Space Elevator Development
« Reply #27 on: 06/18/2018 07:08 am »
I dont think many people realise how high a space elevator has to be. GEO is at approximately 35,786 km (22,236 mi) above mean sea level, and this is the minimum height for a space elevator, using a large counterweight. Most designs use extra cable above  GEO height requiring a total length around 70,000km (43,750 mi).
Traveling at train speeds a shuttle is still going to take weeks to get to orbital height. Using current materials a tapered cable is required which will be probably miles thick at the GEO point as it has to support the mass of cable, plus shuttle.

Offline J2m1s

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Re: Space Elevator Development
« Reply #28 on: 06/24/2018 03:51 pm »
I figured out a indirect way to make a smaller space elevator, doesen't need to be 36000km, but a few hundreds, I am really happy to explain my method so others would develop it based on it, but I am afraid of plagiarism, so please tell me how to protect and publish my method.

Offline alexterrell

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Re: Space Elevator Development
« Reply #29 on: 06/24/2018 04:16 pm »

It cannot be built ground-up like tower. Most of it has to be built from from up to down. So most of the mass has to be first lifted to GEO.
Many proposals have the first strand lowered from GEO. Once that is anchored, climbers take ever more strands up from the surface.

Offline meberbs

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Re: Space Elevator Development
« Reply #30 on: 06/25/2018 06:18 am »
I figured out a indirect way to make a smaller space elevator, doesen't need to be 36000km, but a few hundreds, I am really happy to explain my method so others would develop it based on it, but I am afraid of plagiarism, so please tell me how to protect and publish my method.
Patents are designed for exactly this situation, though in theory you won't get one unless the idea actually could work and hasn't been thought of before.

If you just want attribution and aren't trying to make money off of it, then there is no need for a patent. Posting online creates an effectively permanent record, so depending on your preferences you can just post a paper, including just on this forum, with however much identifying information you want to share, at least your name, and maybe a picture or basic biographical information such as where you went to school. (Up to you to balance how much detail vs. your own privacy)

You most likely have not thought of a novel working idea here. Wikipedia has a summary of many of the alternative launch concepts that could theoretically work. https://en.wikipedia.org/wiki/Non-rocket_spacelaunch There are probably some others out there, but generally just variations on things from that article. If your idea is not already on that page, it is likely that your idea couldn't work and you are missing something.

Offline alexterrell

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Re: Space Elevator Development
« Reply #31 on: 06/25/2018 09:24 am »
Now that we have boosters that are smart enough to land and perform sub orbital manouvres, is it time to revist the rotovator, or momentum exchange tether concept?

This was described by Zubrin in
Hypersonic Airplane Space Tether
Orbital Launch (HASTOL) System

It relied on a suborbital Mach 12 place to transfer the payload to a tether, which would then whip it up to a Geostationary or Lunar transfer orbit.

According to the abstract:
Quote
The tethers can be built today using presently available commercial fibers. The tethers are long, typically 400 to 1600 km (1300 to 5300 kft) in length. The total mass of the space tether plus the Tether Central Station typically will be 30-200 times the payloads being handled.

That probably doesn't make it suitable for a BFR - too big. But it would be ideal for smaller payloads like a Dragon capsule.

Could the Falcon 9 booster reach Mach 12?

Offline aceshigh

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Re: Space Elevator Development
« Reply #32 on: 06/28/2018 01:06 am »
Relying on memory but it says that each trip on the elevator would be days. That strikes me as very limiting.

The elevator is thousands of miles long and you are basically in a car. This limits you to the speeds of fast car. So the journey takes several days.

So... even if Space Elevator technology was feasible (and it isn't), it'd be a bit like saying:  "Let's not fly from one side of America to the other - that's sooo routine. There's this great new tech called a car.. let's drive instead!!!"  ???

Really?!? Wow!

Really? So you never heard of SHIPS travelling from the west to the east coast much slower than a car and having to go south to go through the Panama Canal?

Or about ships transporting cargo from US to China, China to South America, etc, etc?

Why not do all of that by AIRPLANE?


When you need to transport LOTS and LOTS of cargo, you can´t pay the price of an airplane. Too expensive. And even a BFR would be tooooo expensive to transport for example 100 thousand tons of Earth food and tech in exchange for Asteroid metals.


Space Elevators have that in mind. Expensive to build (like the Panama canal) but once it's built, objetive is the cost of transport to be in the order of a few cents of a dollar per kilogram (cargo itself, even food, must be more expensive per it's weight than the transport of the same weight)

Offline CameronD

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Re: Space Elevator Development
« Reply #33 on: 06/28/2018 03:07 am »
When you need to transport LOTS and LOTS of cargo, you can´t pay the price of an airplane. Too expensive. And even a BFR would be tooooo expensive to transport for example 100 thousand tons of Earth food and tech in exchange for Asteroid metals.


Space Elevators have that in mind. Expensive to build (like the Panama canal) but once it's built, objetive is the cost of transport to be in the order of a few cents of a dollar per kilogram (cargo itself, even food, must be more expensive per it's weight than the transport of the same weight)

You describe a system that not only requires large amounts of unobtainium to build but defies all known laws of nature to be "expensive" to build (I admire your optimism) but then say that, once built, the objective is the cost to "be in the order of a few cents of a dollar per kilogram"??  ???

If you could perhaps kindly explain how something impossible to construct at any time in the foreseeable future could possibly be cheaper to operate than tech that already exists, then I'll reconsider my point of view.
« Last Edit: 06/28/2018 03:09 am by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline TrevorMonty

Re: Space Elevator Development
« Reply #34 on: 06/28/2018 03:28 am »
Issac Arthur has excellent Youtube channel with video on Space Elevators plus whole lot more grand ideas on lowering cost of space access.

NB He's added a lot new videos over last few months.

Offline gbpfan12

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Re: Space Elevator Development
« Reply #35 on: 06/28/2018 03:28 am »
How about Issac Arthurs favorite Orbital Rings. Their much better then space elevators.



Edit: lol just posted then saw the above post.
« Last Edit: 06/28/2018 03:30 am by gbpfan12 »

Offline A_M_Swallow

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Re: Space Elevator Development
« Reply #36 on: 06/28/2018 08:25 am »
When you need to transport LOTS and LOTS of cargo, you can´t pay the price of an airplane. Too expensive. And even a BFR would be tooooo expensive to transport for example 100 thousand tons of Earth food and tech in exchange for Asteroid metals.


Space Elevators have that in mind. Expensive to build (like the Panama canal) but once it's built, objetive is the cost of transport to be in the order of a few cents of a dollar per kilogram (cargo itself, even food, must be more expensive per it's weight than the transport of the same weight)

You describe a system that not only requires large amounts of unobtainium to build but defies all known laws of nature to be "expensive" to build (I admire your optimism) but then say that, once built, the objective is the cost to "be in the order of a few cents of a dollar per kilogram"??  ???

If you could perhaps kindly explain how something impossible to construct at any time in the foreseeable future could possibly be cheaper to operate than tech that already exists, then I'll reconsider my point of view.


Using current materials space elevators can be built on the Moon, Mars and large asteroids. It is Earth that has the material strength problem.

Offline aceshigh

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Re: Space Elevator Development
« Reply #37 on: 06/29/2018 02:31 am »
When you need to transport LOTS and LOTS of cargo, you can´t pay the price of an airplane. Too expensive. And even a BFR would be tooooo expensive to transport for example 100 thousand tons of Earth food and tech in exchange for Asteroid metals.


Space Elevators have that in mind. Expensive to build (like the Panama canal) but once it's built, objetive is the cost of transport to be in the order of a few cents of a dollar per kilogram (cargo itself, even food, must be more expensive per it's weight than the transport of the same weight)

You describe a system that not only requires large amounts of unobtainium to build but defies all known laws of nature to be "expensive" to build (I admire your optimism) but then say that, once built, the objective is the cost to "be in the order of a few cents of a dollar per kilogram"??  ???


even the strenght needed to build it on Earth is FAR from being unobtainium. No need to be as strong as scrith (Ringworld fantasy material, tensile strenght similar to strong nuclear force).

Carbon nanutubes, graphene and diamond nanothreads are all candidates. Making them of good quality at macroscopic level is an ENGINEERING problem, not a physics problem.

If it's not a physics problem, it's not unobtainium.


Quote
If you could perhaps kindly explain how something impossible to construct at any time in the foreseeable future could possibly be cheaper to operate than tech that already exists, then I'll reconsider my point of view.

expensive infrastructure. Once in place, not much energy should be needed to move very large amounts of cargo.

Just like ships and the panama canal are expensive, but end up being cheaper for bulk transportation than the much faster airplanes.

On the other hand, moving a huge cargo ship to transport a few people would be very expensive.

ships become cheap because of the sheer amount of cargo they can transport.


that is the vision for the space elevator. As you thicken the cable and as you use same infrastructure (including counter weight) you can get more and more cargo into space. Slowly but cheaply. Rockets still being used for moving people and urgent cargo.

Offline LMT

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Re: Space Elevator Development
« Reply #38 on: 07/09/2018 04:02 am »
When you need to transport LOTS and LOTS of cargo, you can´t pay the price of an airplane. Too expensive. And even a BFR would be tooooo expensive to transport for example 100 thousand tons of Earth food and tech in exchange for Asteroid metals.


Space Elevators have that in mind. Expensive to build (like the Panama canal) but once it's built, objetive is the cost of transport to be in the order of a few cents of a dollar per kilogram (cargo itself, even food, must be more expensive per it's weight than the transport of the same weight)

You describe a system that not only requires large amounts of unobtainium to build but defies all known laws of nature to be "expensive" to build (I admire your optimism) but then say that, once built, the objective is the cost to "be in the order of a few cents of a dollar per kilogram"??  ???

If you could perhaps kindly explain how something impossible to construct at any time in the foreseeable future could possibly be cheaper to operate than tech that already exists, then I'll reconsider my point of view.


Using current materials space elevators can be built on the Moon, Mars and large asteroids. It is Earth that has the material strength problem.

We found the martian case quite approachable.  A "Mars Lift" could be the first proof-of-concept, and a first commercially viable space elevator. 

Notably:

The martian tether is much shorter than a lunar tether (20,000 km vs. perhaps 80,000-200,000 km). 

Short length and low gravity allow for construction with materials having specific strength in the same order-of-magnitude as existing CNT film. 

The need for one-way cargo delivery to Mars justifies an unpowered elevator system, a simplified "rappeller" delivering cargo to the surface, only. 

Also Dr. Lades successfully demonstrated that an off-equator tether avoids Phobos, passively and always; as illustrated at left.

« Last Edit: 07/09/2018 06:00 pm by LMT »

Online JonathanD

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Re: Space Elevator Development
« Reply #39 on: 09/10/2018 03:04 pm »

Dunno if they've been brought up, but Liftport has some interesting stuff on their site: http://www.liftport.com/lunar-elevator.html

If NASA is determined to build the Deep Space Gateway, which in its current incarnation is pretty useless, why not scale it up and use it as a counterweight for a lunar space elevator?  The lunar case makes the most sense to me for a number of reasons:

1) dV requirements for conventional lunar landing really suck, a lunar space elevator would make delivering tonnage to the lunar surface way more realistic (either to an equatorial region or to an alternative polar tether as per this graphic https://upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Lunar_space_elevator.svg/760px-Lunar_space_elevator.svg.png)

2) And obviously gets resources from the lunar surface back up to an easy-to-get-to orbit (He3, water, or LH2/LOX).

3) If the counterweight stored LH2 and LOX, you would have a legit refueling station for interplanetary travel.  This would be an enabler for a lot of different cycler-type spacecraft that would make regular trips to Mars and back, for instance.  This would reduce fuel requirements for something like BFS, or give greater fuel margin to allow BFS to slow down upon Mars approach and save the wear & tear on the thermal protection system.

4) While the moon's slow rotation would mean either a pretty long cable or a pretty big counterweight, from the materials side it's very much something that is within manufacturing capabilities of today thanks to low gravity and lack of atmosphere. 

5) Because of the relatively small gravity well, the lunar space elevator tether would not need to be tapered at all, either in terms of size or strength - that means you could have a dramatically simpler system in terms of repair and maintenance, and even a large "pulley" system which would allow cargo to move in both directions simultaneously.

This seems like a no-brainer for a permanent presence on the moon.  Yes it would be expensive, but over the long run would more than pay for itself compared to making direct conventional landings on the moon and other planetary bodies on an ongoing basis.

Offline TrevorMonty

Re: Space Elevator Development
« Reply #40 on: 09/10/2018 03:57 pm »
The elevator cables are vunerable to meteoroid impact damage. Even thin cable stretched over 100,000s kms has large surface area. A meteoroid big enough to break it would be very rare but lots of little hits from specs of dust adds up to lot of accumulated damage over a year.


Online JonathanD

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Re: Space Elevator Development
« Reply #41 on: 09/10/2018 04:28 pm »
The elevator cables are vunerable to meteoroid impact damage. Even thin cable stretched over 100,000s kms has large surface area. A meteoroid big enough to break it would be very rare but lots of little hits from specs of dust adds up to lot of accumulated damage over a year.

There would definitely need to be a specialty car that inspects and repairs the cable as it transverses it.  Or in a pulley scenario it could be done at either end.  Also would mean in the unlikely event of a significant impact on one of the cables, the endpoints could "brake" the cable and other half could be used to maintain the connection.

Offline A_M_Swallow

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Re: Space Elevator Development
« Reply #42 on: 09/11/2018 12:55 pm »
Due to the low rotational speed of the Moon the lunar elevator would have to be enormous. Going through EML-1 the ribbon would be 230,000 km + 56,000 km = 286,000 km long. More than half way to Earth.

Offline CuddlyRocket

Re: Elon Musk: glass geodesic domes
« Reply #43 on: 02/09/2019 10:01 pm »
Unlike on Earth, where an elevator to geosynchronous orbit is just marginally physically possible, putting in an elevator to areosynchronous orbit has no technical issues ...

Apart from Phobos, which is in a lower orbit and which crosses the equator four times a day.

Offline Jcc

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Re: Re: Elon Musk: glass geodesic domes
« Reply #44 on: 02/09/2019 11:11 pm »
Unlike on Earth, where an elevator to geosynchronous orbit is just marginally physically possible, putting in an elevator to areosynchronous orbit has no technical issues ...

Apart from Phobos, which is in a lower orbit and which crosses the equator four times a day.

According to Arthur C. Clarke, you can oscillate the tether and make Phobos jump rope. No problem!

Offline Paul451

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Re: Space Elevator Development
« Reply #45 on: 02/10/2019 06:23 am »
Unlike on Earth, where an elevator to geosynchronous orbit is just marginally physically possible, putting in an elevator to areosynchronous orbit has no technical issues
Apart from Phobos, which is in a lower orbit and which crosses the equator four times a day.

However, Phobos makes a great anchor-mass for an orbital tether to the top of the atmosphere. Much. much shorter than an elevator, much less loading on the tether allowing a higher safety factor and payload/tether mass ratio. You still need to fly from the surface up to the bottom of the tether, but that's ~700m/s. Trivial. Likewise, when landing on Mars: by descending from the tether, you eliminate orbital re-entry entirely. A small ground-to-Phobos shuttle would thus allow a huge payload mass, and could service any number of sites around the equator.

Adding a similar sized tether to the outward side of Deimos means you can capture incoming ships from Earth, or throw them into Mars-Earth transfer without propellant. (Or out to the asteroid belt.) A pair of tethers on the inboard sides of the moons allows propellantless transfer between them too. So launching ships from Mars surface to Earth would take 700m/s delta-v, ditto capturing ships from Earth. And the total length of such a tether network would still be less than a single "elevator", and still stronger for a given tether thickness.

(with credit to Hollister David)
« Last Edit: 02/13/2019 02:29 pm by Lar »

Offline rarchimedes

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Re: Re: Elon Musk: glass geodesic domes
« Reply #46 on: 02/13/2019 04:31 am »
Off-topic:
However, Phobos makes a great anchor-mass for an orbital tether to the top of the atmosphere. Much. much shorter than an elevator, much less loading on the tether allowing a higher safety factor and payload/tether mass ratio. You still need to fly from the surface up to the bottom of the tether, but that's ~700m/s. Trivial. Likewise, when landing on Mars: by descending from the tether, you eliminate orbital re-entry entirely. A small ground-to-Phobos shuttle would thus allow a huge payload mass, and could service any number of sites around the equator.

Adding a similar sized tether to the outward side of Deimos means you can capture incoming ships from Earth, or throw them into Mars-Earth transfer without propellant. (Or out to the asteroid belt.) A pair of tethers on the inboard sides of the moons allows propellantless transfer between them too. So launching ships from Mars surface to Earth would take 700m/s delta-v, ditto capturing ships from Earth. And the total length of such a tether network would still be less than a single "elevator", and still stronger for a given tether thickness.

(with credit to Hollister David)

It would seem cheaper to push a large asteroid or even Phobos itself into an areostationary  areocentric orbit, permanently solving the anchoring issue for your tethering series. A great deal of work on these subjects has been done by a little company called Tethers Unlimited and whose web site has much information on that and on additive manufacturing in space, all fodder for discussions such as we are having here.

With an areostationary elevator to the surface, there will be no need to expend fuel to access the elevator and follow on in your tether series. Since skipping off the atmosphere seems a chancy process with such a thin atmosphere, using Phobos and/or Deimos as catchers and throwers for craft from Earth seems to cut the risk factors involved and provide basically free delta-V.

One of the big problems on Mars will be point to point transport over long,dry, dusty and rocky distances. With an anchor in a semi-areostationary orbit, moving slowly enough to be manageable, a tether could pick up objects and drop them in far away places. Otherwise, we will need to constantly use rockets to move stuff around, which strikes me as about as inefficient as you can get. A tether can be given slack to allow attaching and detaching loads before the tether accelerates back to its orbital speed, which could be below 200 klicks.

Offline rarchimedes

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Re: Space Elevator Development
« Reply #47 on: 02/13/2019 04:36 am »
Just remembered an odd question that comes to mind. What is the periodicity of Phobos crossing any particular part of the equatorial line?
« Last Edit: 02/13/2019 02:29 pm by Lar »

Offline Paul451

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Re: Re: Elon Musk: glass geodesic domes
« Reply #48 on: 02/13/2019 04:55 pm »
However, Phobos makes a great anchor-mass for an orbital tether to the top of the atmosphere. Much. much shorter than an elevator, much less loading on the tether allowing a higher safety factor and payload/tether mass ratio. You still need to fly from the surface up to the bottom of the tether, but that's ~700m/s. Trivial.
It would seem cheaper to push a large asteroid or even Phobos itself into an areostationary  areocentric orbit,

Hell no. The mass of Phobos is ten trillion tonnes. You aren't moving that anywhere.

With an areostationary elevator to the surface, there will be no need to expend fuel to access the elevator

As I said, 700m/s is trivial. It's less than required to hop between sites on Mars' surface. (Which means that hopping up to the tether, ferrying to another site on the equator, and dropping off to land, requires less fuel than a direct point-to-point hop.

Since skipping off the atmosphere

Not sure what that refers to.

One of the big problems on Mars will be point to point transport over long,dry, dusty and rocky distances. With an anchor in a semi-areostationary orbit, moving slowly enough to be manageable, a tether could pick up objects and drop them in far away places.

That's what a Phobos tether is.

A tether can be given slack to allow attaching and detaching loads before the tether accelerates back to its orbital speed, which could be below 200 klicks.

That's doesn't work with orbital mechanics.

Offline LMT

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Omaha Trail
« Reply #49 on: 02/25/2019 07:45 pm »
Passing Phobos

Unlike on Earth, where an elevator to geosynchronous orbit is just marginally physically possible, putting in an elevator to areosynchronous orbit has no technical issues ...

Apart from Phobos, which is in a lower orbit and which crosses the equator four times a day.

According to Arthur C. Clarke, you can oscillate the tether and make Phobos jump rope. No problem!

Martin Lades demonstrated that an off-equator tether terminus solves that problem.  You can simply drive the tether terminus away from the equator and thereby shift the entire tether poleward.  So repositioned, the tether avoids Phobos passively forever.  A transporter weighted with rock could do the job.

Base displacement as little as 10 degrees -- ~ 600 km -- could be adequate to ensure passive Phobos avoidance.  (Working assumption is CNT tether film having effective specific strength slightly higher than current best CNT film specific strength.)

Previous post.

More info:  2017 British Interplanetary Society presentations:  Space Elevator Feasibility and the Omaha Trail.

« Last Edit: 02/26/2019 02:56 am by LMT »

Re: Space Elevator Development
« Reply #50 on: 01/12/2021 12:43 pm »
Looks like I'm reviving this thread after a while. Does anyone know if serious space elevator development initiatives are underway as of 2021? I  know companies like LiftPort are working on this, but these companies have been around for more than a decade with little sign of progress. Realistically is there any chance of a company unveiling a space elevator in the near future?

Offline Frogstar_Robot

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Re: Space Elevator Development
« Reply #51 on: 01/12/2021 02:15 pm »
Looks like I'm reviving this thread after a while. Does anyone know if serious space elevator development initiatives are underway as of 2021? I  know companies like LiftPort are working on this, but these companies have been around for more than a decade with little sign of progress.

I was in LiftPort's Kickstarter which raised $110,000, but no rewards were ever sent out.

Quote
Realistically is there any chance of a company unveiling a space elevator in the near future?
Realistically, no. Space elevators are likely to exist only in the province of dreamers for a long time.

If we have cheap rockets, I think the business case for space elevators disappears.
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Offline Genial Precis

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Re: Space Elevator Development
« Reply #52 on: 01/14/2021 06:13 pm »
Looks like I'm reviving this thread after a while. Does anyone know if serious space elevator development initiatives are underway as of 2021? I  know companies like LiftPort are working on this, but these companies have been around for more than a decade with little sign of progress. Realistically is there any chance of a company unveiling a space elevator in the near future?
The basic material properties to make a space elevator possible on Earth are orders of magnitude off, and even if they weren't, the business case for a many-billion megaproject that takes a long time to build and can't make very much revenue even when it's finished is more orders of magnitude off. Also, Starship is much more imminent than anything you could do even if the first two weren't true, and Starship is very likely to further murder the business case.

Space elevator companies are grift. Let me put this in context. They would need to build an object much larger than the Three Gorges dam, out of materials that don't exist but would surely be much more expensive than concrete, before they could earn a cent of revenue.

Offline Seamurda

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Re: Space Elevator Development
« Reply #53 on: 01/28/2021 09:40 pm »
Quote from: Frogstar_Rob
Realistically, no. Space elevators are likely to exist only in the province of dreamers for a long time.

If we have cheap rockets, I think the business case for space elevators disappears.

To a degree cheap rockets make most of the infrastructure heavy non-rocket spaceflight systems more achievable. They also create uses which build the demand that could conceivably allow such a structure to be financed.

Also rockets hit various limitations on access to population centres, emissions, noise, light pollution before they get as common as airliners.

An orbital ring would for example massively useful as a global transportation, power generation and transmission system.

Offline aceshigh

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Re: Space Elevator Development
« Reply #54 on: 01/30/2021 01:47 am »
wrong topic. ANd I don´t know how to delete this.
« Last Edit: 01/30/2021 01:56 am by aceshigh »

Offline Paul451

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Re: Space Elevator Development
« Reply #55 on: 01/30/2021 06:39 am »
wrong topic. ANd I don´t know how to delete this.

Top right side of your own comment. (Quote, Modify, Remove.)

Offline daedalus1

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Re: Space Elevator Development
« Reply #56 on: 01/30/2021 07:01 am »
Quote from: Frogstar_Rob
Realistically, no. Space elevators are likely to exist only in the province of dreamers for a long time.

If we have cheap rockets, I think the business case for space elevators disappears.

To a degree cheap rockets make most of the infrastructure heavy non-rocket spaceflight systems more achievable. They also create uses which build the demand that could conceivably allow such a structure to be financed.

Also rockets hit various limitations on access to population centres, emissions, noise, light pollution before they get as common as airliners.

An orbital ring would for example massively useful as a global transportation, power generation and transmission system.

Space elevators can only service the equator, so even more restricted than rockets.

Offline Seamurda

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Re: Space Elevator Development
« Reply #57 on: 01/30/2021 10:19 pm »
Quote from: Frogstar_Rob
Realistically, no. Space elevators are likely to exist only in the province of dreamers for a long time.

If we have cheap rockets, I think the business case for space elevators disappears.

To a degree cheap rockets make most of the infrastructure heavy non-rocket spaceflight systems more achievable. They also create uses which build the demand that could conceivably allow such a structure to be financed.

Also rockets hit various limitations on access to population centres, emissions, noise, light pollution before they get as common as airliners.

An orbital ring would for example massively useful as a global transportation, power generation and transmission system.

Space elevators can only service the equator, so even more restricted than rockets.

They can only get to an equatorial orbit but if you use multiple strands those strands can come down pretty much anywhere on earth.

If you wish to use a space elevator to reach a none equatorial orbit you can get there by doing a plane change from geo which needs much less delta V and can use low thrust engines and/or aero breaking.

I was also mainly talking about orbital rings and feathers which can go to any orbit you want.

Offline Paul451

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Re: Space Elevator Development
« Reply #58 on: 01/31/2021 09:32 am »
An orbital ring would for example massively useful as a global transportation, power generation and transmission system.
Space elevators can only service the equator, so even more restricted than rockets.

Orbital rings aren't space elevators. They can be built at any inclination and eccentricity.

However, pedantically, even space elevators can be made non-equatorial. However, it increases the stress on the tether, increasing the material strength requirements. Of course, if you are worried about boring things like material strength requirements, then space elevators aren't possible for Earth, so the subject is moot.

Online darkenfast

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Re: Space Elevator Development
« Reply #59 on: 01/31/2021 11:09 am »
How do the space elevator proposals plan to deal with traffic in LEO moving at very high relative velocity? Sooner or later there would be a conflict between the tower and a satellite that has lost control or is being used deliberately as a weapon.
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Offline Paul451

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Re: Space Elevator Development
« Reply #60 on: 02/01/2021 06:14 am »
How do the space elevator proposals plan to deal with traffic in LEO moving at very high relative velocity? Sooner or later there would be a conflict between the tower and a satellite that has lost control or is being used deliberately as a weapon.

In general, just removing them. If you have a space elevator, you can build enough infrastructure to target and remove any satellite that threatens the tether.

Offline Paul451

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Re: Space Elevator Development
« Reply #61 on: 02/01/2021 06:16 am »
I was also mainly talking about orbital rings and feathers which can go to any orbit you want.

Feathers?

Offline daedalus1

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Re: Space Elevator Development
« Reply #62 on: 02/01/2021 06:26 am »
Once you have cheap reusable rockets to orbit, which is happening now. The impossible dream of space elevators to GEO becomes even more impossible.

Offline Seamurda

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Re: Space Elevator Development
« Reply #63 on: 02/02/2021 01:14 pm »
I was also mainly talking about orbital rings and feathers which can go to any orbit you want.

Feathers?

Tethers - Skyhooks et al.

Offline spacenut

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Re: Space Elevator Development
« Reply #64 on: 02/20/2021 01:30 pm »
A space elevator might work on the moon, or even Mars, but on earth the gravity well as well as sometimes extreme weather conditions might make a space elevator very impractical.

I could see the moon as a possible space elevator first location.  Gravity is lower, no atmosphere.  It could possibly run from LL1 to the Moon's surface. 

As someone said, new large cheap rockets might make a space elevator unnecessary, as well as large SEP tugs for large bulk non-perishable cargo. 

Offline aceshigh

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Re: Space Elevator Development
« Reply #65 on: 02/22/2021 06:20 pm »

As someone said, new large cheap rockets might make a space elevator unnecessary, as well as large SEP tugs for large bulk non-perishable cargo.

I still see large cheap rockets akin to cheap airplanes.

You will still want to have ports and railroads to move very large amounts of cargo, even if the infrastructure to build a port for shipping containers is more expensive than building a 2km tarmac runway.

Offline Paul451

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Re: Space Elevator Development
« Reply #66 on: 02/23/2021 04:50 am »
I still see large cheap rockets akin to cheap airplanes.
You will still want to have ports and railroads to move very large amounts of cargo, even if the infrastructure to build a port for shipping containers is more expensive than building a 2km tarmac runway.

Problem is that, given how difficult it is to build a space elevator from Earth (likely impossible with known materials, given any kind of engineering safety factor), even if atomically-perfect nanotube-woven-ribbon was capable of supporting its own weight over that length, the amount of cargo that could pass up the tether each year would be low. It isn't really a "bulk transport".

In a way, it's rockets that are the cargo ships. Space elevators are supersonic maglev trains in undersea vacuum tunnels.

Online darkenfast

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Re: Space Elevator Development
« Reply #67 on: 02/23/2021 08:12 am »
I would think that a tower would be vulnerable to any LEO object that cannot be kept under active control. All these orbits cross the equator.

To me, space elevators are one of those sci-fi ideas like building a monorail on pylons across, or a tunnel under, the ocean: maybe you can someday solve the challenges, but is it really going to be better than all the container ships and airliners that you will have at the time?
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Offline daedalus1

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Re: Space Elevator Development
« Reply #68 on: 02/23/2021 09:34 am »
It certainly won't be for humans. If you could send it up at 40 mph (which is faster than any lift on earth, and they're mains powered..these certainly wont be) it would take a month. But on the bright side, you won't be weightless until you get there.

Offline aceshigh

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Re: Space Elevator Development
« Reply #69 on: 02/23/2021 04:41 pm »
I still see large cheap rockets akin to cheap airplanes.
You will still want to have ports and railroads to move very large amounts of cargo, even if the infrastructure to build a port for shipping containers is more expensive than building a 2km tarmac runway.

Problem is that, given how difficult it is to build a space elevator from Earth (likely impossible with known materials, given any kind of engineering safety factor), even if atomically-perfect nanotube-woven-ribbon was capable of supporting its own weight over that length, the amount of cargo that could pass up the tether each year would be low. It isn't really a "bulk transport".

In a way, it's rockets that are the cargo ships. Space elevators are supersonic maglev trains in undersea vacuum tunnels.

No, then rockets would still be airplanes, and space elevators would be supersonic maglev trains in undersea vacuum tunnels.

Meaning... one is expensive to transport cargo, not efficient, and to VAST VAST columes, quite polluting.

And the other is for the moment, technologically unfeasible.

Offline Frogstar_Robot

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Re: Space Elevator Development
« Reply #70 on: 03/10/2021 03:11 pm »
FYI


MARCH 9 - MARCH 11, 2021

ELEVATORS
S P A C E   E D I T I O N

From Icarus to Jack and the beanstalk, to ancient Anasazi legends – we have dreamed of ascending to the heavens. Usually, these are cautionary tales. “Don’t tempt the gods.” “Don’t rise above your station.” And yet, we rise. First, we dreamed of flying - we achieved it. Then we dreamed of launching - done. The next step was a “giant leap” on the Moon. Now what? Elevators.

Blue Marble Week | March 2021 will explore:
- Gravitational Elevators (Lunar Space Elevator Infrastructure) and
- Centripedal Elevators (Space Elevators from Earth)

We’ll look at both through the lenses of
1) Hardware, 2) Business, 3) Outreach, and 4) Framework

Join us for a host of speakers discussing the topics of:
1) Workforce Development
2) Infrastructure and Space Hardware
3) The Linkage of Cyber and Space
4) Transportation and Industrial Bases

Online, free to register. I didn't get any notice of this event, so missed a day already.
« Last Edit: 03/10/2021 03:12 pm by Frogstar_Robot »
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Offline Lodrig

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Re: Space Elevator Development
« Reply #71 on: 03/17/2021 06:38 pm »
A space elevator might work on the moon, or even Mars, but on earth the gravity well as well as sometimes extreme weather conditions might make a space elevator very impractical.

I could see the moon as a possible space elevator first location.  Gravity is lower, no atmosphere.  It could possibly run from LL1 to the Moon's surface. 

As someone said, new large cheap rockets might make a space elevator unnecessary, as well as large SEP tugs for large bulk non-perishable cargo.

Agree with one amendment, now that our interest in the moon is focused on the poles a Y shaped elevator that brackets the moon at 2 point near the poles would be ideal.  On decent you can choose which pole to arrive at and arrive on the surface close to said pole without having to make a long trek from the equator to the poles.  Lastly the attachment point is now tangent to the surface rather then vertical which should make logistics much easier as the elevator climber can be a horizontal train.

Offline Vultur

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Re: Space Elevator Development
« Reply #72 on: 03/17/2021 07:20 pm »
Once you have cheap reusable rockets to orbit, which is happening now. The impossible dream of space elevators to GEO becomes even more impossible.

I am skeptical of space elevators, but very-high-infrastructure-cost/low-cost-per-kg alternative launch schemes in general (space elevators, space fountains, launch loops, etc.) probably require a much larger launch market than currently exists to make sense.

So reusable rockets might actually be a necessary intermediate step (lowering costs enough to greatly increase the size of the market).

Offline Frogstar_Robot

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Re: Space Elevator Development
« Reply #73 on: 03/17/2021 07:33 pm »
Some videos from the Blue Marble week on Space Elevators are hosted on the Liftport Group youtube page https://www.youtube.com/c/Liftport/videos. I watched some of the Day 2 proceedings.

I have to say, I am disappointed with the quality of work here. The guy hoping to build the Voyager space station didn't understand that the elevator goes to GEO, not LEO. That lead to a very confusing exchange with the elevator guy.

The guy presenting a business case for Space Based Solar to mitigate Global Warming, which he said could only be done with 6 space elevators. However, in his comparison with Starship, he was 1000 times out on his numbers (yes, 3 OOM!). In questions, he revealed he was "going off Elons tweets". He apparently missed the tweet where Elon said there would be a fleet of Starships, not just one!

So these are the guys hoping to spend billions on space infrastructure. I remain highly confident that a Space Elevator for Earth will never be built, let alone 6.
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Offline Vultur

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Re: Space Elevator Development
« Reply #74 on: 03/19/2021 05:58 pm »
The guy presenting a business case for Space Based Solar to mitigate Global Warming, which he said could only be done with 6 space elevators. However, in his comparison with Starship, he was 1000 times out on his numbers (yes, 3 OOM!).

Yeah - given modern thin film solar cells, I wouldn't be surprised if space-based solar power could be done with vastly less mass than the 1970-era O'Neill estimates suggested.

And if a fleet of a thousand Starships ever actually exists (which is far from certain - but way more practical and near-term than a space elevator), that's a *lot* of launch capacity.

Quote
I remain highly confident that a Space Elevator for Earth will never be built, let alone 6.

I think you are probably right. In addition to the inherent difficulty/huge cost, more space development would mean more satellites able to collide with the elevator.

If there is a post-chemical-rocket launch-from-Earth system, I'd think laser launch might be a more plausible one.

Offline Frogstar_Robot

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Re: Space Elevator Development
« Reply #75 on: 03/19/2021 06:19 pm »
And if a fleet of a thousand Starships ever actually exists (which is far from certain - but way more practical and near-term than a space elevator), that's a *lot* of launch capacity.

That is something that favors chemical rockets massively : scalability. Elon can start making a return on investment as soon as he has built one ship.

OTOH, a $20 billion space elevator doesn't make a cent until it is finished. That means a long pay back time, which investors are not keen on.

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Offline Genial Precis

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Re: Space Elevator Development
« Reply #76 on: 03/19/2021 10:49 pm »
A space elevator on Earth would be the largest megaproject ever built and the primary material of construction would be 100 times beyond the strength/weight performance of any existing materials. It's not even remotely competitive with other forms of infrastructure-to-orbit, much less viable on its own.

That's presumably why no one remotely competent to execute is discussing it.

Offline Frogstar_Robot

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Re: Space Elevator Development
« Reply #77 on: 03/20/2021 10:09 am »
Of course, if such a magic super-strength material was developed, which could be manufactured economically in large quantities, that would probably benefit many industries, including chemical rockets.

Obayashi who are at least a major construction company, have a "construction concept" https://www.obayashi.co.jp/en/news/detail/the_space_elevator_construction_concept.html. They estimate the cost at $90 billion, assuming a material is available to build it. Tbh, I think it is just one of those paper exercises large companies do for a bit of publicity.
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