Globus IMP navigation indicator
Mechanical position indicator
On display
Before onboard computers, navigation was solved mechanically: a clockwork drove a globe about eight centimetres across at the orbital period, while a differential accounted for the Earth's rotation. A separate scale showed where landing would occur if the retro-rocket were fired immediately.
The instrument served on Vostok, Voskhod and Soyuz spacecraft until 2002 and outlasted many of the electronic systems meant to replace it. Accuracy was modest, but fault tolerance was absolute.
On display is the instrument with its cover removed: the globe, differential and clockwork are visible.
