Editing Known Space (section)

===Stepping disks===
Stepping disks are a teleportation technology. They were invented by the [[Pierson's Puppeteers]], and their existence is not generally known to other races until the events of ''[[The Ringworld Engineers]]''.

The stepping disks are an outgrowth and improvement of the [[transfer booth]] technology used by humans and other Known Space races. Unlike the booths, the disks do not require an enclosed chamber, and somehow can differentiate between solid masses and air, for example. They also have a far greater range than transfer booths, extending several [[astronomical unit]]s.

Several limitations to stepping disks are mentioned in the ''[[Ringworld]]'' novels. If there is a difference in [[velocity]] between two disks, any matter transferred between them must be accelerated by the disk accordingly. If there is not enough energy to do so, the transfer cannot take place. This becomes a problem with disks that are a significant distance apart on the [[Ringworld]]'s surface, as they will have different velocities: same speed, different direction.