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Graphene at 20: still no sign of the promised space elevator, but here’s how this wonder material is quietly changing the world (theconversation.com)

submitted 3 months ago by [email protected] to c/[email protected]

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[–] [email protected] 16 points 3 months ago (1 children)

We don't need no stinking space elevator!

All we need are SKYHOOKS!

[–] [email protected] 7 points 3 months ago (2 children)

Kursgesat forgets to mention the incredible forces that would put on the payload. NASA funded a study that suggested they start with a jet going mach 10, or 3.5 km/s. The fastest a person has ever gone is mach 6.7 or 2.02km/s. For efficiency sake, you'd want to get up to speed in a reasonable amount of time. I doubt humans can effectively use sky hooks. Could be really good for stuff though

[–] [email protected] 6 points 3 months ago

NASA funded a study that suggested they start with a jet going mach 10, or 3.5 km/s. The fastest a person has ever gone is mach 6.7 or 2.02km/s.

In a jet. In a rocket, just the ISS is going at >7km/s, so obviously it's routine. A (scram)jet would be nicer from a fuel point of view, but you don't need it. In any case, to get to double the velocity with the same acceleration, you just accelerate twice as long - space is always big enough for a pure rocket-type craft (beamed power or gun-type are a different matter).

When it comes to the skyhooks themselves, the study you're thinking of gave a spread of different accelerations for the designs, from <1 G to quite heavy (but manageable for a trained professional).

[–] threelonmusketeers 6 points 3 months ago (1 children)

The fastest a person has ever gone is mach 6.7 or 2.02km/s.

Astronauts on the ISS are currently zipping along at at 7.67 km/s just fine. The issue is acceleration, not speed. Tethers rotate fairly slowly, so the acceleration should be less than that of a rocket launch.

[–] [email protected] 7 points 3 months ago* (last edited 3 months ago) (1 children)

Astronauts on the ISS are currently zipping along at at 7.67 km/s just fine.

And we've all been zipping around the sun at 29.78 km/s since each of our inceptions.

[–] [email protected] 5 points 3 months ago

Our Sun moves around the centre of the Milky Way at a speed of 240 km/s or 864,000 km/h, so do we plus or minus ~30km/s!