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APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 5:07 am
by APOD Robot
Image A Tether in Space

Explanation: One of the greatest unrequited legends of outer space is the tether. Tethers, long strands of material, hold the promise of stabilizing satellites, generating electricity, and allowing easy transportation. Possibly the most ambitious vision of the space tether is the space elevator popularized by Arthur C. Clarke, where a tether is constructed that connects the ground to geosynchronous orbit. One problem is strength - it is difficult to make a long useful tether that does not snap. Pictured here is the deployment of the Tethered Satellite System 1 (TSS-1) by the space shuttle Atlantis in 1992. Like other tested tethers, TSS-1 failed to live up to its promise, although many valuable lessons were learned.

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Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 5:13 am
by neufer
Click to play embedded YouTube video.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 5:26 am
by Boomer12k
Learning all the time....

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Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 9:55 am
by heehaw
Tethers have a long unhappy history in space.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 12:24 pm
by distefanom
I ever wondered why, this kind of scientific investigations (Tethered satellites), NEVER have had a "sequel" of any kind....
Also, even if I'm not prone to the so called cospiration theories, I wonder why this experiment has been readily spread as "unsuccessful" and stopped.
I.e. the cable itself, has been said to containing "bubbles" that may have endangered cable functionality causing the "snap" after a while it was unrolling into space....
Or maybe too many amps (current) passed trough it and, just like a thunder strike, vaporized the metal...
Personally I don't think that engineers, while working and assembling this kind of probe, could have underestimated electrical aspects ... All the appliances at home have a protection against static electricity of some sort...
I understand that scientific investigations usually "jumps into the unknown" but, even with ONE suspect that the satellite tether could have been traversed by so much electrical current, should have triggered the idea on how this suspected dynamo could work and how it could be used in space for various purposes... like satellite propulsion and/or orbit stabilization; nor electrical power source.
I think, instead, that something like "new weapons" could have, instead, triggered the military interest on all this and, this way explaing all this "cover up".
mmmh! It's definitely NOT CLEAR to me.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 1:43 pm
by Dr. Work
The space shuttle's name is Atlantis, not Altantis. Whoever writes these blurbs often doesn't do the greatest job spell-checking his or her work. If APOD ever wants help with that, I'm available!

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 1:45 pm
by Dr. Work
neufer wrote:
Click to play embedded YouTube video.
This reminds me of a limerick:

Imagine a tetherball game.
Centrifugal force is the name
Of the notional thing
That pulls on the string
In a rotating reference frame.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 1:59 pm
by E Fish
I remember reading Clarke's book that they mention here, Fountains of Paradise, when I was in high school. The whole concept of a space elevator was fascinating to me and I always hoped that there might be something to it.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 2:01 pm
by cbarnbau@valdosta.edu
Check into carbon nanotubes as possible construction material for
a Clarke tether.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 2:13 pm
by heehaw
Dr. Work wrote:The space shuttle's name is Atlantis, not Altantis. Whoever writes these blurbs often doesn't do the greatest job spell-checking his or her work. If APOD ever wants help with that, I'm available!
Or maybe Atalantus? Surprised that Atalantus does not have a Wikipedia entry!

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 2:15 pm
by heehaw
E Fish wrote:I remember reading Clarke's book that they mention here, Fountains of Paradise, when I was in high school. The whole concept of a space elevator was fascinating to me and I always hoped that there might be something to it.
https://en.wikipedia.org/wiki/Space_elevator

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 3:06 pm
by Chris Peterson
E Fish wrote:I remember reading Clarke's book that they mention here, Fountains of Paradise, when I was in high school. The whole concept of a space elevator was fascinating to me and I always hoped that there might be something to it.
Given the potential for causing widespread destruction, as well as being a target for the unstable (whose numbers are ever on the rise), I'm glad we are still a long ways from being able to make such a thing.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 3:08 pm
by Chris Peterson
distefanom wrote:I ever wondered why, this kind of scientific investigations (Tethered satellites), NEVER have had a "sequel" of any kind...
I think it's because the use cases aren't that strong, so these experiments end up being quick and cheap exercises shoehorned into existing missions by those able to negotiate such things. There are actually quite a few experiments like that which get flown and never really followed up on.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 4:13 pm
by rstevenson
Chris Peterson wrote:
E Fish wrote:I remember reading Clarke's book that they mention here, Fountains of Paradise, when I was in high school. The whole concept of a space elevator was fascinating to me and I always hoped that there might be something to it.
Given the potential for causing widespread destruction, as well as being a target for the unstable (whose numbers are ever on the rise), I'm glad we are still a long ways from being able to make such a thing.
In Kim Stanley Robinson's Mars trilogy just such an event takes place, to catastrophic consequences. It's all too clear just how vulnerable such a device would be, though it would be incredibly handy if we could build it.

Rob

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 4:37 pm
by Fred the Cat
rstevenson wrote:
Chris Peterson wrote:
E Fish wrote:I remember reading Clarke's book that they mention here, Fountains of Paradise, when I was in high school. The whole concept of a space elevator was fascinating to me and I always hoped that there might be something to it.
Given the potential for causing widespread destruction, as well as being a target for the unstable (whose numbers are ever on the rise), I'm glad we are still a long ways from being able to make such a thing.
In Kim Stanley Robinson's Mars trilogy just such an event takes place, to catastrophic consequences. It's all too clear just how vulnerable such a device would be, though it would be incredibly handy if we could build it.

Rob
I agree. Although terraforming was the main plot driver in Kim Stanley Robinson's Mars trilogy, it was the space elevator that enabled much of the action. And indeed - disruption of its function was the method of choice for the 'terrorists" of day. If we do ever create such technology you'd hope our social issues would have been equally addressed by then. Of course you'd need an actual method for social "science" advancement too. :yes:

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Sun Jan 07, 2018 5:05 pm
by neufer
Fred the Cat wrote:
rstevenson wrote:
Chris Peterson wrote:
Given the potential for causing widespread destruction, as well as being a target for the unstable (whose numbers are ever on the rise), I'm glad we are still a long ways from being able to make such a thing.
In Kim Stanley Robinson's Mars trilogy just such an event takes place, to catastrophic consequences. It's all too clear just how vulnerable such a device would be, though it would be incredibly handy if we could build it.
I agree. Although terraforming was the main plot driver in Kim Stanley Robinson's Mars trilogy, it was the space elevator that enabled much of the action. And indeed - disruption of its function was the method of choice for the 'terrorists" of day.

If we do ever create such technology you'd hope our social issues would have been equally addressed by then. Of course you'd need an actual method for social "science" advancement too. :yes:
  • We've had a few of those, too, from time to time:
https://en.wikipedia.org/wiki/Arthur_C._Clarke#Sexuality wrote:
<<Sir Arthur Charles Clarke, CBE, FRAS (16 December 1917 – 19 March 2008) was close to a Sri Lankan man, Leslie Ekanayake (13 July 1947 – 4 July 1977), whom Clarke called his "only perfect friend of a lifetime", in the dedication to his novel The Fountains of Paradise. Clarke is buried with Ekanayake, who predeceased him by three decades, in Colombo's central cemetery. In his biography of Stanley Kubrick, John Baxter cites Clarke's homosexuality as a reason why he relocated, due to more tolerant laws with regard to homosexuality in Sri Lanka.>>

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Mon Mar 19, 2018 5:35 pm
by Chris1985
A new patent I just read about, will allow space elevators to be built with current materials.
It has multiple tethers at its center ( for greatest strength ) and fewer tethers
as you move away from center  ( for lesser amounts of mass ).
Liftport has plans to build a Lunar elevator from current material.
Using that same material for an Earth based elevator would reach the lunar gravity center
(about 9,000 km AGL) approx. 1/6 G. Add this new concept and you could reach Earth's surface.
We can do this now. Let's get started. What do you think?

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Mon Mar 19, 2018 5:47 pm
by Chris Peterson
Chris1985 wrote: Mon Mar 19, 2018 5:35 pm A new patent I just read about, will allow space elevators to be built with current materials.
It has multiple tethers at its center ( for greatest strength ) and fewer tethers
as you move away from center  ( for lesser amounts of mass ).
Liftport has plans to build a Lunar elevator from current material.
Using that same material for an Earth based elevator would reach the lunar gravity center
(about 9,000 km AGL) approx. 1/6 G. Add this new concept and you could reach Earth's surface.
We can do this now. Let's get started. What do you think?
I think I don't want anything with that destructive potential given our current engineering, maintenance, oversight, and criminal situation. We can't reliably build a pedestrian bridge over a road.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Mon Mar 19, 2018 9:08 pm
by Chris1985
How about a Chinese space station coming down? Sometimes you need to take a risk to make any real progress.
The material must be super light so it would flutter down like a kite. Parachutes could be attached. It will be
stationed to the west of Galapagos Islands and if broken, would fall to the west into open ocean.
$100/lb. to G.E.O. nothing else comes close. Above G.E.O. you get a free ride to the Moon or Mars etc.
Too many positives to not give it a shot if it will work.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Mon Mar 19, 2018 9:50 pm
by Chris Peterson
Chris1985 wrote: Mon Mar 19, 2018 9:08 pm How about a Chinese space station coming down? Sometimes you need to take a risk to make any real progress.
The material must be super light so it would flutter down like a kite. Parachutes could be attached. It will be
stationed to the west of Galapagos Islands and if broken, would fall to the west into open ocean.
$100/lb. to G.E.O. nothing else comes close. Above G.E.O. you get a free ride to the Moon or Mars etc.
Too many positives to not give it a shot if it will work.
A space station falling down is trivial. Worst case, a building or two destroyed and a few people killed. A falling space elevator cable could cause damage across the whole world. No way are we ready for that, and certainly not until humans evolve beyond wars and terrorists.

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Tue Mar 20, 2018 2:47 am
by neufer
Chris1985 wrote: Mon Mar 19, 2018 5:35 pm
A new patent I just read about, will allow space elevators to be built with current materials.
It has multiple tethers at its center ( for greatest strength ) and fewer tethers
as you move away from center  ( for lesser amounts of mass ).
Liftport has plans to build a Lunar elevator from current material.
First build a radio telescope at the L2 Lagrangian point 16.8% beyond the Moon
(where the Moon is ~ 1.75 [~1.168/(4 x 0.168)] the size of the Earth).

And then build a Lunar elevator down to the surface to built an even better protected radio telescope.
https://en.wikipedia.org/wiki/Lagrangian_point wrote:
<<For the Moon, L1 Lagrangian point is located 15.1% in front of the Moon;
the L2 Lagrangian point is located 16.8% beyond the Moon.>>

Re: APOD: A Tether in Space (2018 Jan 07)

Posted: Tue Mar 20, 2018 5:25 pm
by Chris1985
I would love to see those things happen, and with an earth based space elevator,
we could do those things and much more at a very low cost.