Rotating Skyhook

For my last blog post, I wrote about a problem with space travel. This problem was fuel. For this blog, I will be writing my opinion about an idea proposed by scientists in 1976 and 1994 for getting an object into space, which is the main reason for the need for so much fuel and for such powerful engines. This idea is the rotating skyhook.

The idea behind a rotating skyhook is a massive space station in orbit that has a tether, or hook, attached to it that rotates in the direction opposite of the orbit of the station. The orbiting station will allow the hook to stay suspended “from the sky”, hence the name. The opposing orbital spin and tether spin will have the effect of making the hook travel in an epicycloidal pattern around the planet. This means that the hook would be momentarily stationary relatively low in the atmosphere, allowing it to travel deeper into the atmosphere without drag, and allowing the object to be attached to the hook at very low speeds. It also will have the interesting visual effect from the ground of a hook on a tether suddenly descending vertically from the sky, slowing, stopping, and reversing to leave. The hook would lift the object away from the planet and accelerate it so that when it is the farthest distance from the planet, it would be moving very fast, allowing it to enter orbit or leave the planet very efficiently.

There are some problems however. The force of lifting the object into orbit would have an equal and opposite effect on the station. This means that every time an object was lifted, the station would move to a lower orbit. This is not as bad as it sounds, the station could have a small amount of thrust over a large amount of time, balancing to the force to lift the object. This can be achieved by more efficient but less throughput propulsion methods that I will be writing about in some upcoming blog posts. The other problem is that the station would have to be many multiples of the mass of the object being lifted. The tether would also have to be very light and strong, but nothing past what we are capable of. These two problems would lead to an extremely large cost to build.

Overall, in my opinion, this is one of the less outrageous methods of getting to space more efficiently. I feel as though the costs would be massive to build and require cooperation of nations, but that the benefits outweigh the costs.