He described the rings as being for decelerating a ship returning to the Ringworld. For those who don't know, the Ringworld is a ring 93 million miles in radius - one Earth orbit - which would make it 600 million miles long. It started with the mass of a Jupiter sized planet, and it's a million miles wide, about a thousand meters thick. It has three million times the surface area of the Earth. It was built by my species (literary spoiler reference to my screen name).
More precisely the rings would actually have been for accelerating or decelerating any returning space ship, as needed, to match the Ringworld spin rate (770 miles/second). The ship would then just maneuver over to a landing platform once it's matched the spin rate. For "launching" the ship, already traveling at the Ringworld spin velocity while sitting on the platform, would just be "dropped" through a trap door, ala one of these satellites being flung into space and float away at roughly 1 gravity.
The superconducting rings were made from scavanged parts of the original designs steering jets, needed to keep the ring stable with it's star at the center of it's spin. The Ringworld inhabitants who built the system didn't realize that they were endangering the entire Ringworld when they stole the parts for their system and for their Bussard Ramjet space ships, which also used the superconductors. That stuff gets covered in Ringworld Engineers, Ringworld Throne and Ringworld's Children. He also talks about the engineering of Ringworld in a neat essay, Bigger Than Worlds.
Can you tell I'm a bit obssessed? <g>
Protectors were some bad dudes alright,Puppeteers
were terified of them.
That Ringworld is a stunning conception and
creation.Not to mention the sunflowers,floating cities etc
No,protectors didn`t create sunflowers did they?
You mentioned an essay Niven wrote, "Bigger than worlds"
If you would,where do you find it? I can`t locate it.
Thanks