History, Politics And Current Affairs

Yup, although the space elevator faces a more fundamental issue than materials - energy/power. You have to accelerate the cabin up to orbital speed.

That I understand is actually the easy part--like an electrified train power can be carried from ground generators, no need to haul fuel along.

They should be able to figure out away to generate power from the cars going down.

With those new room temperature ambient pressure superconductors, the power problem feels like a lot less of an issue now.

Luigil101 wrote: ↑Thu Aug 03, 2023 3:17 pm With those new room temperature ambient pressure superconductors, the power problem feels like a lot less of an issue now.

Still not confirmed as of yet. Don't count your chickens before they're hatched.

Kunkmiester wrote: ↑Thu Aug 03, 2023 12:33 am https://scitechdaily.com/scientists-cre ... han-steel/

Not quite there yet. And as always, the trick is in the manufacturing. "You've produced 6.7 grams of this wonder material by hand that has the required properties. That's great. When can we get 127 tons of it, with no flaws and properties at least as much as your test sample?"

jemhouston wrote: ↑Thu Aug 03, 2023 10:41 am They should be able to figure out away to generate power from the cars going down.

That's right. Send a car down as a car is going up. Then the mass of the payload is the only thing that needs to added. Once they have lunar or asteroid mining going, send down a cargo that masses the same as the one going up and the only thing needed is to make up efficiency and friction losses.

Even without that, a poor comparison puts a raptor engine at a bit over 6 gigawatts. That's just a large nuclear power plant. A dedicated plant with a few dozen GW would cover it, and probably be a fraction of the cost of the whole thing.

The $/kg to Geosynchronous Orbit of a fully-reusable Starship Super-Heavy and other launch vehicles of its type will be the Space Elevator’s competition to beat.

If I remember the numbers correctly, Starship can lift about 25t into GTO -1800m/s, but for direct GEO you need at least two extra refuelling flight for any decent payload size. And probably 4 to 5 tankers for the full 100t+ to GEO.

Assuming a long-term marginal launch cost of $4m * 5 total flights, nets $20m per 100t+ to GEO, or $200/kg. Currently, I believe the total cost invested into Starship is in the $4b range.

I cannot imagine what it would take to get a Space Elevator to be even remotely competitive with that. Especially given all of the disadvantages and restrictions that are inherent to the concept.

"...room temperature ambient pressure superconductors,..."

As yet, un-verified: No-one has been able to duplicate the uncertain material, no-one has reported robust superconductivity...

'Extraordinary claims require extraordinary evidence', it is not there yet...

But, still, this stuff may contain a trace of 'thin end of wedge', open 'new science', just as buckyballs and skewed graphene did...

Here's my estimate of the rate of collisions between the tether and low orbiting satellites

How's this for an estimate? Assume the satellites fly at 6500 km from the Earths's centre. There are 10000 satellites, with an orbital period of 90 minutes, hence cross the equatorial plane 32 times a day 365 days a year. Say a strike consists of getting within 5m of the centreline of the tether.

So in a year we cover 10000*32*365*2*5 m of the 'orbit' of the tether, which is 2*pi*6500*1000 m long

Every part of the orbital plane of the tether in LEO is struck 28 times a year by a satellite. Current losses of satellites from collisions is about 1 per year.

Obviously some satellites are maneuverable. Also see https://en.wikipedia.org/wiki/Kessler_syndrome

Fun thought, the tech invented by ACC is destroyed by another tech invented by ACC!