Viewing a single comment thread. View all comments

ItsAConspiracy t1_je4ujk1 wrote

Reply to comment by Plate_Of_Soup in What science and technology should be here already (2023) but isn’t? by InfinityScientist

We don't have a cable that can reach to geostationary without breaking under its own weight. It's theoretically possible with nanotubes, but we'd need to mass-produce 7cm nanotubes, line them all up parallel and glue them together, and we're not there yet.

We do have cables that could get to LEO, which would let us build an orbital ring. That'd arguably be even better than an elevator, but it'd take more coordination between countries.

3

Plate_Of_Soup t1_je4wa5s wrote

Halo conspiracy intensifies

Very interesting! Instead of cabling, is there nothing like a high-tech spider silk that could do the do? Or is this equivalent to nanotubes?

1

ItsAConspiracy t1_je593kl wrote

Spider silk is really strong but not as strong as the nanotube cable would be, and not quite strong enough for a space elevator.

With the orbital ring, you only go, say, 150 miles up. You have a ring in any circular orbit around the planet. This ring does not have to be solid; the key is a bunch of hunks of iron, moving at faster than orbital speed. Those are electromagnetically deflected by passing through rings, which are cabled to the ground. The deflection pulls the rings upwards.

Getting to 150 miles altitude is just like a space elevator. After that, you use the momentum of the orbiting metal to launch you to orbital speed. You have to keep accelerating the metal chunks, so you need a bunch of solar panels.

All this can be done with today's technology for a few billion dollars in launch cost, you'd effectively get lots of space elevators instead of just one, and it could get payloads to orbit for $0.05/kg. But you'd need all the countries along a great-circle path around the planet to work together on it.

Before doing all that though we could do a launch loop, same basic idea but it's just a couple thousand miles long, and instead of the metal orbiting the planet it travels in an arc and back along the ground.

2

Plate_Of_Soup t1_je5cnw2 wrote

So 1) geostationary satellites equipped with solar panels from as many points along the great-circle ad possible, 2) spider silk equivalent between the satellites to create the loop, and 3) anchorpoints for payload delivery?

1

ItsAConspiracy t1_je5iiuh wrote

For the orbital ring? Not geostationary. Lots of little rings, say 10 meters wide, with attached solar panels, hanging stationary just 150 miles up, cabled to the ground. They're held up there by the momentum of the iron chunks, circling the earth at faster than orbital speed, each one deflected by the electromagnets of each little ring so it doesn't shoot out to a higher orbit.

Here's a video but that's a more advanced version that's actually solid all the way around the ring.

1

Plate_Of_Soup t1_je5py5y wrote

The narrators combination of drawl and rhotacism is wildly engaging

1

ItsAConspiracy t1_je5rjty wrote

He has a ton of great videos, and there's a subreddit. (And thanks for teaching me a word :)

2