Cosmonauts on board the Soviet Soyuz spacecraft needed to know their position over the Earth to plan contacts with ground stations which were mostly located in the Soviet landmass. In addition, in case of emergency, they had to predict where a retrofire would cause them to land, as it would be embarrassing to come down on the White House lawn.
Today, such navigation displays are integrated into flight software and displayed on “glass cockpit” panels but in the 1960s and 1970s no such wonders existed. So how did the Soviets do it? Gears—lots of gears.
Ken Shirriff had the opportunity to reverse-engineer a Globus unit recently and figure how it coped (or didn’t) with the details of orbital mechanics. Details are posted in “Inside the Globus INK” on his Web log. Interestingly, this unit apparently played a part in the Apollo-Soyuz mission, as its globe display shows U.S. ground stations as well as Soviet ones.