6 ms·
What cable weighs less than half a pound per mile? 200,000 miles 88,000 lb cable No friggin way.
by 34679 7y ago
What cable weighs less than half a pound per mile?
200,000 miles
88,000 lb cable
No friggin way.
- binarymax 7y agoWell since it's in pounds, that's an earth gravity weight measurement. Maybe they're talking about moon weight :) Actually, not using a measurement of mass is a bit of a red flag. EDIT: Perhaps I should read the paper and not rely on science-journalism. At first glance paper looks pretty good in terms of mass measurement and estimation.
- mkl 7y agoYes, that seems to have been misunderstood. The cable that weighs 88,000lb (in the paper, 40,000kg), has a cross-sectional area of 10⁻⁷m²! That won't stand up to much use. If I'm reading (skimming) right, they say "this would only allow transport of weights up to 100kg".
- jandrese 7y ago100kg seems like a barely usable amount of lift. It means you need an in-orbit assembly system for most things you want to launch and I'm pretty sure you're not going to be able to launch a person with life support gear.
- mkl 7y agoYes, it's hard to imagine a cable-crawling machine and its power source being under that mass limit, let alone a payload.
- jandrese 7y agoI had assumed the cost of the crawler was already included in that 100kg figure, but if not then yeah, that's even more marginal. It really can't bring its own fuel source along, it needs to work on beamed power or maybe a current between two parallel tethers.
- perl4ever 7y agoSo, uh...if it can transport 0.25% of its weight, then that kind of implies that the safety margin is of the same approximate order, doesn't it?
- deleted 7y ago[deleted]
- TallGuyShort 7y agoThe paper uses some pretty exotic materials. The one with the lowest density has a strength-to-weight ratio only 8 times that of steel...
- Verdure 7y agoThe linked paper does the math, and suggests Kevlar and Dyneema are strong enough. That said, moon gravity is only 1/7th that of earth.
- senectus1 7y agoI have questions about stuff like, how they stop it icing up... how this magic material handles the temp gradients from the cold of space to the relative warmth of of earth and then when it gets hit by unfiltered sunlight.