Compact jump ships do not enter hyperspace proper; they aim at a star and "glide" along the so-called "interface" between space and hyperspace until the mass at the other end of the jump goal makes them drop out. They exit at light speed and must dump velocity with help of the same jump engine; a ship failing to do so is doomed, and usually a high hazard. There is a limit on maximum jump distance, depending on the ship's drive power and mass; a ship overstretching a jump may "fade", never exiting it. A jump takes several weeks of objective time. Subjectively it can take hours or even several days; this tends to exhaust the body, and the crews need to take rest between jumps. Hani and mahendo'sat stay marginally conscious during jump, but unable to act; usually, they dream. Stsho must drug themselves unconscious to survive jump. Humans can survive it undrugged, but it is a terrible experience to them. No one knows what the other species feel during it, though it is hinted that kif maintain more of their faculties than hani during jump. Jumps can be strung together, but at a commensurate increase in crew discomfort. Ships and space stations communicate by radio, which poses time-lag difficulties. To alleviate them somewhat, heavily trafficked systems usually keep buoys near the jump exit points that serve incoming ships with system-wide scan and traffic information, and also mail. The space stations are universally built as huge doughnuts, the spin maintaining artificial gravity provided by centrifugal force; the Compact has no gravitational-control technology. The spin poses a difficulty when docking, as the ship must precisely coincide with the rotating station wheel. When docked, two sets of grapples, its own and the station's, hold it in place and in mutual clinch: a ship can undock forcibly, but that is bound to damage the station and is subject to substantial fines. Tankers and miners dock at the central hub for the transfer of materials. Dockside transport is mostly electric carts and trucks of all sizes, but many move around on the docks on foot. Different species build ships in different fashions; the methane-breather ships seem haphazardly constructed to the oxygen breathers. Hani ships such as "The Pride of Chanur" are based on mahendo'sat technology. The dock grapples are at the prow of the ship. Behind it is the habitat area with a rotating carousel which provides "gravity" during inertial flight and in jump; the bridge, galley and living quarters – including crew and passenger quarters – are all located in that ring.