I was being very simple. I used skyhook as informal and humorous and did not know that it had a technical meaning in this context. I was thinking more of what is commonly called a space elevator but did not look up the details, e.g., synchronous orbit or some such.

Really I was just commenting on the spider silk with carbon fibers that might add some of the needed strength and also permit sending power to whatever was crawling up the string of the elevator.

Again, I was just commenting on the OP and the fiber and not trying to get into space elevators in detail.

Oh, I figured you meant it. In that case carbon fiber is stronger, more conductive, and cheaper. Why bring up space elevators if you have no interest in saying or learning something about them?

> Why bring up space elevators if you have no interest in saying or learning something about them?

Because when I looked into space elevators, the main problem was getting the cable strong enough for its weight. So, with spider silk, already amazingly strong, with carbon, a first guess, or hope, for an application would be for a space elevator.

So, in response to the OP, I mentioned the cable, string, whatever, for skyhooks, space elevators, or whatever.

Again, my understanding is that space elevators are well enough understood and the main issue is just the cable. So, given the OP, I mentioned the cable, mostly just the cable, without digging into the well understood details of space elevators. I wasn't trying to discuss space elevators in general, just the cable and just in response to the OP.

If there was a big counterweight out at the far end of the cable, and it was sufficiently long enough, wouldn't the centrifugal force acting on the weight counteract the kilos lifted?

No, that doesn't work for anything less than a space elevator or the other devices I mentioned. A space elevator is tied down to the earth, and constantly trying to fly off into space. A skyhook is basically nothing more than a LEO satellite with a very, very long rope hanging off it. If you pull on the rope, you pull the satellite down since there is no centrifugal force besides the inertia keeping it in orbit.

If you make a very heavy counterweight, it just delays the inevitable pulling down, and its that much harder to get into orbit. There's no point.

While the energy imparted to the object being leunched is the same, you would be able to use high-ISP thrusters like ion engines to boost the counterweight back up. They can't be used lower down though, due to not having enough thrust for use in the atmosphere. This would have the advantage of raising the average ISP during the launch, thus having to use less propellant overall.

It might even be possible to use tether-based propulsion for the counterweight, which wouldn't need any propellant at all but push against the Earths' magnetic field.

Landing on the moon also pulls it down, also landing on existing satellites. There is no special nature of ropes that "pulls down". Secondly there's no reason why we couldn't take a space object and use it as the very heavy counterweight.