By Sputnik, 80mileshigh, and Nautilus.
Everything you need to play in the universe of 2001: A Space Odyssey. EXCEPT for Discovery, Leonov, and Pod, available from dbartles. New for v3.1: Soviet Gagarin moon lander and Komarov inner-system transport, Korolevgrad Mars base, cargo handling, upper stages, satellites and probes, new bases, new stations, and more. Older features: Orion spaceplane with booster stage or drop tank, Orion II cargo plane, Titov V Soviet Spaceplane, Station V, Aries Ib and others, Moonbus. Includes Clavius, Tycho, Tchalinko, Lunar Observatory, Lowell Base on Mars, and more.
v3.11 Re-compiled for Orbiter 2010. Pod and Leonov not yet available for Orbiter 2010.