[seer]

If you somehow manage to get magnetic fields involved, so you are not afraid of friction with the cable itself, at 1.3 max apparent acceleration/deceleration (after a turnover) and including earth’s gravity you get 116min to geostationary.

If you account for various inefficiencies like taking it slow in the lower atmosphere Ant whatnot, it still should be in the matter of hours. So totally feasible and even comfortable.

[adwn]

> If you somehow manage to get magnetic fields involved, so you are not afraid of friction with the cable itself, at 1.3 max apparent acceleration […]

This means that half-way after 58 minutes, the climber is traveling at 0.3 * 9.81 m/s² * 60 * 58 ~= 10.2 km/s ~= 36,720 km/h (!!!) relative to the cable. A tiny imperfection or wobble is going to make the climber crash into the cable, destroying both.

A climber with a mass of 10 tonnes requires 10^4 kg * 1.3 * 9.81 m/s² ~= 127.5 kN of force to accelerate at 1.3 g. At the ~56 minute mark, the climber reaches a speed of ~9,888 m/s. This means it requires a power output of 127.5 kN * 9888 m/s = 1.26 GW (!!!) to achieve this acceleration, plus overhead for the power electronics and transmission. Even at a voltage of 1 kV, that's around 1,500,000 A (!!!) of current that you have to transmit and invert.

If you have a way to reliably transfer that amount of power without touching the cable which is moving at 10 km/s relative speed, or with touching but without immediately melting the cable or the collector, let me know :-)

> So totally feasible

lol no

[ben_w]

> A tiny imperfection or wobble is going to make the climber crash into the cable, destroying both.

A maglev train is several centimeters from the rail; if someone made the carbon nanostructures (the only known material strong enough are atomically precise carbon nanotubes or graphene, but the entire length has to be atomically precise you can't splice together the shorter tubes we can build today) this badly wrong, the cable didn't survive construction.

> Even at a voltage of 1 kV, that's around 1,500,000 A

Why on earth would you do one kilovolt? We already have megavolt powerlines. That reduces the current needed to 1500 A. 1500 A on a powerline is… by necessity, standard for a power station.

We even already have superconductor cables and tapes that do 1500 A, they're a few square millimeters cross section.

[ben_w]

A more relevant criticism of that peak velocity is that it significantly exceeds Earth escape velocity (and is 6/7ths of solar EV from here) and therefore wastes energy: https://en.wikipedia.org/wiki/Escape_velocity#List_of_escape...

[adwn]

Oh, and 10 tonnes is bus-sized. For infrastructure at that scale, you want trains at the very least, and those are on the order of 1,000 tonnes. Multiply force, power, and current by 100 accordingly.