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3 of these wires anchored to one spot, and constant pull upward
would prevent the rope from bending down, and would save
much energy.
The structure relies only on tensility and would collapse without
being continuously pulled up. But still, only a tiny rocket is then
needed to send the last
stage into space.
Next rockets reach the wire top independently, and reuse it.
Launch loop
https://en.wikipedia.org/wiki/Launch_loop
mentioned in my anno [notexactly, Feb 26 2017]
My idea's better. See anno
https://www.youtube...watch?v=J1MAg0UAAHg
notexactly's Launch Loop link explained in a video [pashute, Jan 25 2018]
[link]
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@pashute,
If the wire was wrapped around a helium-filled tube to make it weightless, it wouldn't need the planes. [+] |
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If the wire was instead a looped iron pipe of diameter ~50
mm and length ~4 Mm, half of which was covered by
another slightly wider non-ferrous pipe, that half of which
was arched up to ~80 km above ground, and the other half
of which was at ground level, and the entirety of which was
pushed along at ~14 km/s by a station at each end, it
wouldn't need the planes. It also wouldn't need the rocket
until apogee (for circularization/perigee raising). [link] |
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This idea is better than a launch loop, since it uses tension
only, and no length structure. So until some height you would
be using much cheaper airlift technology (or even LTA) and
once at the top you have a triangular tether to pull you out. |
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This seems promising but it's a little unclear. Are
the 3 wires almost vertical? Can electric planes fly
that high? Do they use propellers, or electrically
heated jet turbines, or ion wind thrusters, or
something else? |
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Or are there 3 107 km wires at the top forming a
triangle, and 3 more connecting the corners of the
triangle to a common anchor on earth? In which
case they're still pretty high, and can they still fly? |
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A related idea:
Have something the shape of a launch loop, but
instead of super fast wire holding it up, have a
series of electric planes tethered very closely to it
to hold it up. Or maybe attached like a maglev
train. They fly along it from one end to the other. |
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They definitely need their wings, to generate lift.
They might not need steering, they can be
attached to the loop for that. Or maybe it would
help stabilise things. And they might not need a
propeller, maybe they can pull forward on the
loop, I'm not sure. |
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The maglev has a second track, for payloads to be
shot into orbit (which need to go much faster than
the planes). The top of the loop has a lower
pressure atmosphere, hopefully enough to support
the plane but not enough to obstruct the payload. |
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I read that the SR-71 Blackbird can reach altitudes
over 90,000 feet when fuel is low. That may be as
much as we can do with a jet engine, so something
else is needed. |
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A better reference point than the SR-71 is the Helios solar
electric plane. That sustained fight over 96000 feet for 40
minutes. Of course that's not 107km, and it wasn't trying to
hold up a very long tether. |
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