Re:Japan starts space elevator experiments
by zamadatix on Sunday September 02, 2018 @10:40PM
(#17899917)
Then you have an enormously large tower held up by nothing but its own strength instead of being naturally pulled into space. Also takes additional delta-v to get satteliges into common orbits post release.
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Re:Japan starts space elevator experiments
by angel_j on Monday September 03, 2018 @03:03AM
(#17900944)
This is arguably more doable than cables. I've been told that it's completely possible to build steel structures several miles tall (and the main reason we don't is b/c elevators become a problem).
Re:Japan starts space elevator experiments
by chriswarbo on Monday September 03, 2018 @03:20AM
(#17901009)
We can build massive steel towers (e.g. https://en.wikipedia.org/wiki/X-Seed_4000 would be 4km tall), but they would still be nowhere near space (one common definition of reaching space is https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line which is at 100km).
A space elevator would reach at least 36,000km to hit geostationary orbit ( https://en.wikipedia.org/wiki/Geostationary_orbit ). Most designs are even longer, to provide a counterweight.
No known material could support a tower that tall (towers need compressive strength; elevators need tensile strength). It would need to rely on 'active support' or 'dynamic structures', like a space fountain ( http://www.orbitalvector.com/Orbital%20Travel/Space%20Founta... )
Re:Japan starts space elevator experiments
by asib on Monday September 03, 2018 @04:38AM
(#17901300)
A friend of mine who studies engineering told me that masonry has infinite compressive strength meaning, in theory, it's possible to build monumental structures out of stone.
Re:Japan starts space elevator experiments
by chriswarbo on Monday September 03, 2018 @04:52AM
(#17901359)
The base needs to be large enough to support the weight, so you get less of a tower and more of a mound (like the great pyramids).
We can get to about 9km using stone by climbing Mount Everest.