ot----------10 million pound rotary table

the Soviet Union and Russian Confederation relies upon launch complex at Baikonur
as primary departure point for orbital lift vehicles

unlike US heavy lift rocket launches which undergo a takeoff rotation--thruster actuated---until recently russian spacecraft required constant launch azimuth adjustment up to the moment of lift off

this was accomplished by what is likely to be the largest rotary table --specifications of which appear to be protected--but with certain capacity of 5000 metric tonnes


two clips

50 year old footage of Baikonur rotational mechanism --

YouTube


brief footage of launch day platform motion---scroll to 6:30

YouTube

Early "Space Launch Vehicles" (LVs) were essentially variants of Intermediate Range Ballistic Missiles (IRBMs) and Inter-Continental Ballistic Missiles (ICBMs). For warfighting, their flight paths were intended to be along a spiral arc in a Great Circle plane defined by the launch site and target locations; for a spaceflight launch, in a Great Circle plane containing the launch site.

Guiding the LV along its intended fight path required both 1) a Missile Guidance Set (MGS) able to determine the LV's location and orientation during flight, and 2) an ability to control the attitude of the LV as it flies.

A typical MGS would contain a 3-axis gyroscopically-stabilized Stable Platform (to provide a reference for LV attitude sensing) carrying 3 mutually-perpendicular accelerometers, allowing LV location to be derived.

To simplify calculations performed by the in-flight MGS, 1) the innermost Stable Platform gimbal wants to be perpendicular to the Great Circle containing the flight path, and 2) one of the attitude-control actuators wants to influence LV rotation around the innermost Stable Platform gimbal axis.

To satisfy these wants, the LV would be aligned before launch so that 1) the LV control planes are orthogonal to the intended flight path, and 2) the innermost gimbal of the MGS is perpendicular to the intended plane of flight and local vertical.