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Japan is taking us one step closer to a space elevator.
Elon Musk may not believe in space elevators yet, but Japan is taking a step forward to realise the dream of travelling to space by elevators instead of the traditional rocket.
A team of researchers from Japan's Shizuoka University and other institutions will conduct the first test in space this month as part of a project to build a space elevator, Japan's The Mainichi reported last week. The space elevator essentially ferries people and cargo shipments in an elevator car travelling on a cable connecting Earth to a space station.
This test is the first exploring the movement of a container on a cable in space. Two ultra-small cubic satellites measuring 10 centimeters on each side connected by a steel cable about 10 metres long will be carried from Kagoshima's Tanegashima Space Center to the International Space Station on Sept. 11.
From there, the connected satellites will be launched and a motorised container acting as an elevator car will travel along the cable and have its journey recorded via a camera attached to the satellites.
The project's technical advisor, Japan's construction giant Obayashi Corporation, is also working on a similar project, though it previously said it expects to deliver a space elevator by 2050.
(Score: 2) by Immerman on Tuesday September 04 2018, @03:52PM (3 children)
Hey, we're getting better at the "big gun to launch things into space" bit- heck, we've had some viable ideas for 50 years now - assuming you're willing to spend the cash. And Spinlaunch and others are working on more cost-effective technologies. And we've got a number of "flying cars" in late-stage production, though the price typically puts them well out of range of the masses.
Beanstalk space elevators though... yeah. Multi-walled carbon nanotubes seem to have the strength-to-weight ratio to do the job, barely, once we can mass-produce long lengths of them (could be quite soon with MIT having worked out industrial-scale graphene production). But they'd only have a ~30% safety margin, while considering the risks if the thing broke we probably want something better than the 900% margin commonly used for bridges and the like. And that's probably not possible as graphene appears to be pushing up against the theoretical limits of tensile strength for atom-based matter (and I'm not holding my breath waiting for stable neutronium). Could work great on Mars or the moon though, if/when we eventually get to the point that such a thing would make sense.
Skyhooks though could make great sense as space elevators, and could be made useful using current mass-produced carbon-fiber cable(assuming it survives in orbit okay). They could also complement well with other atmosphere based launching systems - you don't need to reach anywhere near orbital velocity to dock with the lower end, which could even match speed with the atmosphere. Skyhooks plucking cargo pods off of extreme-altitude dark-sky airship platforms?
(Score: 0) by Anonymous Coward on Tuesday September 04 2018, @04:30PM (1 child)
Mars ... perhaps, but Moon? It rotates too slowly, thus lunarstationary orbit would require too large distance, requiring too long tether and the station at top of the tether orbit being unstable, prone to disturbances by Earth's and Sun's gravity.
(Score: 3, Interesting) by Immerman on Tuesday September 04 2018, @05:59PM
You are absolutely correct. However there are still two spots where a Lunar beanstalk is possible - the closest and furthest points on the Moon, where the beanstalk will pass through the Earth-Moon L1 or L2 points with a counterweight somewhere beyond that. In those cases the gravitational dynamics of the Earth-Moon system will keep the cable stable, despite the fact that it wouldn't otherwise be possible.
There's even been talk of a Lunar L1 elevator whose far tip extends quite close to the Earth (relatively speaking) until it's moving at the same 460m/s as the Earth's surface, which would allow for pure-vertical launches to "grab on" to the tether and then climb to the L1 point through (potentially) much more efficient mechanical means.
The outer moon of Mars meanwhile is already at very nearly the right position for a beanstalk counterweight, though the inner moon might have to be eliminated, or some really clever resonances maintained in the beanstalk to keep out of its way.
(Score: 0) by Anonymous Coward on Tuesday September 04 2018, @07:35PM
Assuming you're simultaneously willing to spend the cash, and not on the "civilized world"'s shit-list; else we'll just kill your rocket scientist, and then where will you be?