One of the status windows dinged. Guppy was starting the spin-up of Farm-3. After a lot of debate filled with discussion of gyroscopes, compressed-air propulsion, and traditional JATO units, Homer had settled on a very old-school system for spinning up the orbital farms, which we were still using. We tethered four drones to the rim with cables, ninety degrees apart, and had them fly in circles until we achieved the proper RPM. Primitive, but effective.