[isgb]

> Space elevators are actually a possible idea being considered by scientists. > The hard part is making a strong enough cable. And finding enough elevator music...

Most engineers would bring up a lot more issues than just finding a strong cable. Also, most attempts with e.g. carbon nanotubes have been abandoned ages ago https://www.newscientist.com/article/2093356-carbon-nanotube....

- We don't have a good ascent mechanism other than rockets - and then we might just use rockets without building an elevator. - We don't have a good (and safe) descent mechanism. - Maintenance? Protection from space debris? Protection from oscillations? Ground-protection if the elevator collapses?

This is dyson-sphere level of fiction. We can do back-of-the-napkin calcualtions on how things would work, but the practicalities make it completely impossible or impractical.

[seanc]

Kim Stanley Robinson's description of a Martian space elevator falling and wrapping twice around the entire planet convinced me that they aren't a good idea.

https://www.kimstanleyrobinson.info/content/clarke

[indoordin0saur]

A fictional representation of a thing exaggerated for dramatic effect and to create plot tension shouldn't really convince you of many things at all. They're rarely accurate portrayals.

[enraged_camel]

A version of this also happens in the first season of Foundation, the Apple TV series based on Asimov's novels.

[ben_w]

In adition to being fictional, what would happen on Mars does not reflect what would happen on Earth as the Martian atmosphere is so much thinner than ours.

[datadrivenangel]

Skyhooks may allow for much easier access to space within the limits of likely practical carbon nanotube based structures. A rotating tether that orbits the planet could be timed to 'catch and throw' supersonic aircraft into space. Lots of engineering still required, but potentially actually feasible compared to space elevators.

[bombcar]

All we have to do is make the global religion require bringing a rock to a specific location; after long enough we’ll have a mountain so high it extends out of the atmosphere!

[kubanczyk]

This presents a considerable risk of splitting English into several languages, none of them intelligible with the others.

[rigmarole]

Related and recommended: Greg Egan “Phoresis” a sci-fi novel of two twin planets in extreme proximity to each other. (I think I read it in one of his anthologies.)

[hermitcrab]

To get to the Kármán line (100k) a mountain with a 60 degree slope would require a base of 115km. A cone with 115km diameter base has a volume of 3.5×10^5 km^3. Which is 3.5x10^14 m^3, which is about 10^15 kg of rock. So it is going to take you a while!

[honkostani]

The material is actually not a problem, if you consider active structures. https://en.wikipedia.org/wiki/Active_structure https://en.wikipedia.org/wiki/Space_fountain

Then again, when doing mega structures, a launch loop is more plausible.

[mrkickling]

You didn't even mention the music!

[thijson]

I think a space elevator on the Moon would be more practical, pointing towards earth. The gravity force is smaller, so existing materials could work. There's not as much of an atmosphere to deal with. It would go past the L1 point between earth and the moon. It could be extended from the poles, where it's most likely where bases might exist.

[Symmetry]

Impractical on Earth given existing technology, but there are a lot of bodies in the solar system which have enough gravity to make them worth while but where they're small enough that the materials needed are ones we have right now. The Moon in particular.

[michaelbuckbee]

In John Scalzi's Old Man's War, there is a discussion of how the more advanced society that they're interacting with deliberately put a space elevator on Earth, not because it was the easiest or cheapest solution, but as a sort of constant reminder of just how much more technologically sophisticated they were.

[cmpb]

Really great book (and series). Though it's not "hard sci-fi" by any means, the technology feels real enough to keep my brain from focusing on the holes and enjoy the fun philosophical and ethical problems that Scalzi comes up with

[gizmo686]

Isn't the entire point of the space elevator to be the ascent/descent mechanism?

Once you have the cable up, you can grab onto it and pull yourself up.

[bisby]

A space elevator doesnt just take you to the karman line (like in the OP website), to get to orbit, you'd need to get up to geostationary height. That's 22,000 miles.

What's the best way to pull yourself directly vertical along a cable for 22,000 miles?

What's the best way to descend 22,000 miles quickly, but also with a braking mechanism that isn't going to require a heat shield?

Some sort of slow cable car going at 10mph even is going to take 2200 hours... 1000mph is going to take 22 hours still. That's a full day to orbit even going REALLY fast. And getting up to 1000mph vertically, for a sustained 22 hours... that's not an easy feat.

And if the goal is just to get up past the karman line and use the elevator as a stage 1 for a rocket launch and detaching from the elevator while suborbital is fine, then it's a one way trip, and still need to re-enter the old fashion way.

The scale of space makes all of the problems far more complicated (edit: not just the cable strength issue, but traversing the cable)

[kingkawn]

Doesn’t the weight of the cable itself let alone any payload preclude this from becoming real based on all plausible material science

[reaperducer]

Most engineers would bring up a lot more issues than just finding a strong cable.

He did. The elevator music!