Japan starts space elevator experiments • Hacker News Board

Re: Japan starts space elevator experiments

#11

Post by newnewpdro » Sun, Sep 02, 2018, 7:45 PM UTC

sandworm101 wrote: post #5

ourmandave wrote: post #3

The cars would travel at up to 200kph and arrive at the space station eight days after departure from Earth. These early cable experiments are important, but someone should also be working on the composing an 8 day Elevator Muzak score that won't drive you insane.

Music? The first four days will be safety announcements. The last four will be debates as to who is responsable for cleaning up all the vomit. A week of near-zero-g in a room with 30 people will not be fun.

Is humor against HN rules? I regularly see such posts being downvoted and it doesn't make sense to me.

Re: Japan starts space elevator experiments

#12

Post by robotrout » Sun, Sep 02, 2018, 7:47 PM UTC

tarzip wrote: post #7

rietta wrote: post #4

The experiment sounds great. But should this work and a real cable to orbit is built, what happens when the cable snaps!? Can such a structure be made failsafe?

That's what safeties are for! We already have a lot of engineering around making elevators safe. TLDR the elevator will clamp on to the rails to slow the free fall. Neat info below on snapping elevator cables and some of the things that would help you. https://science.howstuffworks.com/science-vs-myth/everyday-m...

The rails? The car will travel over a stationary structure, not be pulled up by a pulley like a conventional elevator is. So it is failure of that stationary structure that we are talking about.

Re: Japan starts space elevator experiments

#13

Post by KineticLensman » Sun, Sep 02, 2018, 7:47 PM UTC

rietta wrote: post #4

The experiment sounds great. But should this work and a real cable to orbit is built, what happens when the cable snaps!? Can such a structure be made failsafe?

Kim Stanley Robinson [0] explores some of the failure modes when bad actors are involved. Bad actors with serious weapons. People on the satellite end get flung off into space, the cable wraps itself around the equator, and people on the elevator had better hope that there are nearby spacecraft to pick them up.

[0] https://en.wikipedia.org/wiki/Mars_trilogy

Re: Japan starts space elevator experiments

#14

Post by Torkel » Sun, Sep 02, 2018, 7:48 PM UTC

sandworm101 wrote: post #2

Carbon nanotubes are cool, but i will believe space elevators possible once someone shows me a carbon nanotube rope i can climb with. I'd settle for a bike or motorcycle chain. A nanotube-based shoelace would be worth a noble prize or two.

Given strength and size and other properties that carbon nanotube ropes would need have... Wouldn't a carbon nanotube shoelace be like the worst idea ever? ...strong as a steel cable, but so thin as to be hard to see and handle. And brittle and not so good at bending. => First it slices up your hands when you tighten it and then it breaks when you tie it :)

Re: Japan starts space elevator experiments

#15

Post by yohann305 » Sun, Sep 02, 2018, 7:49 PM UTC

i remember reading here on HN someone explaining why space elevators are not possible. I can't recall why, but he/she had very convincing arguments.

Anyone here remember that thread and can link it back here? Thanks

Re: Japan starts space elevator experiments

#16

Post by pier25 » Sun, Sep 02, 2018, 7:49 PM UTC

I know nothing about physics... but wouldn't the space station need to counter the cable tension?

Re: Japan starts space elevator experiments

#17

Post by DoreenMichele » Sun, Sep 02, 2018, 7:50 PM UTC

newnewpdro wrote: post #11

sandworm101 wrote: post #5

Earlier quoted context omitted.

Music? The first four days will be safety announcements. The last four will be debates as to who is responsable for cleaning up all the vomit. A week of near-zero-g in a room with 30 people will not be fun.

Is humor against HN rules? I regularly see such posts being downvoted and it doesn't make sense to me.

Most humor can be categorized as "insubstantive comments" and those are discouraged.

It is possible to crack a joke here and get it upvoted, but it's hard to pull it off. I even once had a joke upvoted by quite a lot,* like 50 points or something, but most jokes are downvoted not because humor is forbidden, but because insubstantive comments are discouraged.

Some humor is downvoted for being uncivil because a lot of humor is basically poking fun at people or mocking them. A lot of humor is not nice at all. HN tries to meet a very high bar for civility.

* Under my old handle and it hit 59 points:

https://news.ycombinator.com/item?id=14996229

Re: Japan starts space elevator experiments

#18

Post by ghaff » Sun, Sep 02, 2018, 7:50 PM UTC

jessaustin wrote: post #10

tarzip wrote: post #7

Earlier quoted context omitted.

That's what safeties are for! We already have a lot of engineering around making elevators safe. TLDR the elevator will clamp on to the rails to slow the free fall. Neat info below on snapping elevator cables and some of the things that would help you. https://science.howstuffworks.com/science-vs-myth/everyday-m...

What rails? They're not going to run more than one of these difficult-to-build structures up for each elevator. There will be a single cable, and the car will climb it. What happens if the cable snaps will depend on how far up the car is. Low enough, and it will descend to the surface on a builtin parachute. High enough, and it will perform some portion of an orbit, before descending on its parachute.

Presumably you could have redundant cables. But two almost adjacent cables would still be exposed to many single points of failure, especially any caused by a deliberate attack on the system.

And just a cable falling could be a significant disaster by itself.

Re: Japan starts space elevator experiments

#19

Post by arethuza » Sun, Sep 02, 2018, 7:50 PM UTC

sandworm101 wrote: post #5

ourmandave wrote: post #3

The cars would travel at up to 200kph and arrive at the space station eight days after departure from Earth. These early cable experiments are important, but someone should also be working on the composing an 8 day Elevator Muzak score that won't drive you insane.

Music? The first four days will be safety announcements. The last four will be debates as to who is responsable for cleaning up all the vomit. A week of near-zero-g in a room with 30 people will not be fun.

"near-zero-g"

Why would it be "zero-g" you're not in orbit?

Re: Japan starts space elevator experiments

#20

Post by sandworm101 » Sun, Sep 02, 2018, 7:52 PM UTC

arethuza wrote: post #19

sandworm101 wrote: post #5

Earlier quoted context omitted.

Music? The first four days will be safety announcements. The last four will be debates as to who is responsable for cleaning up all the vomit. A week of near-zero-g in a room with 30 people will not be fun.

"near-zero-g" Why would it be "zero-g" you're not in orbit?

You are moving from ground (1g) to geostationary orbit at zero. It will be a slow progression from one to the other (with a very slight lateral acceleration) but imho once below .5g anyone who is going to get air/sea/space sick wont see much difference.