Completely off-topic, but what's the latest thinking on space-elevators? Is there any active research on them? I thought that carbon nanotubes or diamond nanothreads were likely candidates for the cable material.
Toray carbon fiber to carry SpaceX's Mars ambitions
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Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#12My only issue with carbon fiber is that it is not very easily recycled. Aluminum, on the other hand, is quite trivially recycled. So while spaceships made from CFRP are great in the short-to-medium term (a single spaceship can get a lot more use), I hope that we figured out how to recycle CFRP sooner rather than later.
Why would you be worried about recycling spacecraft at this point in history? Up until the last 2 years, practically all spacecraft either burned up in the atmosphere, crashed into the ocean or land, landed permanently on another body, or are now sitting in a museum somewhere if they were designed to return. Recycling the material in spacecraft is simply a non-issue.
Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#13Completely off-topic, but what's the latest thinking on space-elevators? Is there any active research on them? I thought that carbon nanotubes or diamond nanothreads were likely candidates for the cable material.
Materials science isn't there yet, and the investigation is still in the more general material research phase.
We're decades off. You're asking about the state of supersonic air travel while researchers are still figuring out how to smelt aluminum.
Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#14My only issue with carbon fiber is that it is not very easily recycled. Aluminum, on the other hand, is quite trivially recycled. So while spaceships made from CFRP are great in the short-to-medium term (a single spaceship can get a lot more use), I hope that we figured out how to recycle CFRP sooner rather than later.
Aerospace aluminum isn't as easily recycled as beer cans.
If you're building a space ship you have very tight tolerances and specifics needed for the alloying of the metals you use. The aluminum in aircraft is full of strange things that need to be removed for general use aluminum and definitely need to be removed for building new aircraft.
You're right that melting and re-casting aluminum is really cheap and efficient for beer cans, it's not so much the same for aerospace aluminum.
When it comes down to spaceships, the energy used to produce them is usually a very small portion of the total cost of the mission and we don't make very many of them – recycling isn't and shouldn't be a priority.
The Falcon 9 burns 110,000 liters of kerosene every launch, if it were made of carbon fiber, maybe it wouldn't matter how the structure was disposed.
Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#15Completely off-topic, but what's the latest thinking on space-elevators? Is there any active research on them? I thought that carbon nanotubes or diamond nanothreads were likely candidates for the cable material.
Still a lot of active research going on. The biggest issues that need to be resolved are currently with the cable material. There has been a surprising amount of progress in the last few years with creating longer carbon fibers, but its still nascent and has a minimum of 5-10 years of work. Probably much more.
Then even when the cable strength and length issues are satisfactorily resolved, there are lots of other logistics to deal with.
I think any future barriers to the elevator(s) will be more regulatory than technological in the future.
Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#16My only issue with carbon fiber is that it is not very easily recycled. Aluminum, on the other hand, is quite trivially recycled. So while spaceships made from CFRP are great in the short-to-medium term (a single spaceship can get a lot more use), I hope that we figured out how to recycle CFRP sooner rather than later.
Maybe, we need to think about recycling carbon fiber as.. In recycling the fibers get shorter.. Could not that be re-applied to a different industry as far as re-using the carbon fiber? Body Armour for soldiers as the shorter fibers would be of use there?
The problem isn't fiber length. The problem is that the fibers are impregnated with resin, with strong chemical bonds.
Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#17Completely off-topic, but what's the latest thinking on space-elevators? Is there any active research on them? I thought that carbon nanotubes or diamond nanothreads were likely candidates for the cable material.
Probably the biggest barrier to space elevators is exactly what SpaceX and Blue Origin are doing - safe, reliable, and eventually (relatively) inexpensive rockets will make the large fixed costs of setting up a space elevator uneconomical.
Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#18Completely off-topic, but what's the latest thinking on space-elevators? Is there any active research on them? I thought that carbon nanotubes or diamond nanothreads were likely candidates for the cable material.
Still a lot of active research going on. The biggest issues that need to be resolved are currently with the cable material. There has been a surprising amount of progress in the last few years with creating longer carbon fibers, but its still nascent and has a minimum of 5-10 years of work. Probably much more. Then even when the cable strength and length issues are satisfactorily resolved, there are lots of other log…
I'm not sure what "future barriers to the elevator(s) will be more regulatory than technological" means. Like, right now, the barriers are firmly technological.
From the perspective of a hypothetical future in which all the technological problems have been solved, the barriers might be regulatory. But that seems tautological.
Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#19Completely off-topic, but what's the latest thinking on space-elevators? Is there any active research on them? I thought that carbon nanotubes or diamond nanothreads were likely candidates for the cable material.
The issues are huge and probably insurmountable. For example: where would you site it? It has to be equatorial so it can be below the geostationary counterweight. Just the motion of the cable from the eccentricity in the earth's rotation and orbit would probably tear the cable apart (imagine what the foundation of the base station would have to be, and how it would buckle and lift as the earth rotates).
The space elevator is an idea that sounds cool but is fucking dumb if you think about it for more than ten minutes, like the idea of accelerating ships to near light speed, when every hydrogen atom in the void will shred your hull like a cosmic ray.
Re: Toray carbon fiber to carry SpaceX's Mars ambitions
#20Completely off-topic, but what's the latest thinking on space-elevators? Is there any active research on them? I thought that carbon nanotubes or diamond nanothreads were likely candidates for the cable material.
Probably the biggest barrier to space elevators is exactly what SpaceX and Blue Origin are doing - safe, reliable, and eventually (relatively) inexpensive rockets will make the large fixed costs of setting up a space elevator uneconomical.
It seems like there is a wall in reliability with getting chemical rockets much more reliable than about 99% - 99.5%. SpaceX and Blue Origin are doing cool things, but I don't see them being any more reliable than previous generations of chemical rockets.
If an elevator could provide more 9s of reliability, that could be huge.