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Space Elevator

(neal.fun)
1773 points kaonwarb | 1 comments | | HN request time: 0s | source
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jvanderbot ◴[] No.45643427[source]
Very cool. One thing I wish was better shown: space is close, it's just hard to go up. Our liveable breathable atmosphere is razor thin compared to the size of earth.

In most cases, 100km is less than the distance between sizeable metropolitan areas. It's a day long bike ride. Air runs out less than a bus ride across town. A 15k jog/hike would put you in the stratosphere. Those jet aircraft that seem so high are closer than that. Closer than your friends house or the local stadium probably.

Look at a map or globe with that in mind and everything feels so thin!

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messe ◴[] No.45643658[source]
> it's just hard to go up

Going up is the comparatively easy part, it's not exactly rocket science. Going fast enough sideways so you stay up there is the tricky bit.

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block_dagger ◴[] No.45646224[source]
It's NOT rocket science?
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Retric ◴[] No.45646256[source]
You can reach space using air breathing jets. You can’t stay in space using air breathing jets.
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CobrastanJorji ◴[] No.45646750[source]
I don't think there are any physics reasons why it'd be impossible, but certainly we can't do it with existing technology. You'd need an air breathing jet that could get a vehicle to go about five or six times faster than any current such engine has ever achieved (i.e. around mach 20-30), which is perhaps ridiculous, but I don't think it's necessarily impossible, just something we don't know how to do. There have been some (failed) efforts to get there, like the X-30.
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1. tatjam ◴[] No.45648469[source]
Well you can't reach a high orbit using air breathing engines because your impulse must be given within the atmosphere, and then your trajectory inevitably re-intercepts the atmosphere (unless you achieve an escape trajectory) and would decay quickly. You can get around this by packing a small rocket engine and circularizing on apogee!