Wasserfall

The Wasserfall Ferngelenkte Flakrakete (German for Waterfall Remote-Controlled A-A Rocket, also known as Aggregat 5) was a World War II guided surface-to-air missile developed at Peenemünde, Germany. One of the German Wunderwaffen, the Wasserfall design was used as a basis for both the American Hermes-A1 missile and a Soviet research programme under the codename R-101 after World War II.

Guidance was to be a simple radio control MCLOS, Manual Command to Line Of Sight, system for use against daytime targets, but for night-time use a new system known as Rheinland was under development. Rheinland used a transponder in the missile for locating it in flight (as read by a RDF, radio direction finder, on the ground) and a radar unit for tracking the target. A simple mechanical computer guided the missile into the tracking radar beam as soon as possible after launch, using the transponder and RDF to locate it, at which point the operator could see both "blips" on a single display, and guide the missile onto the target as during the day. Steering during the launch phase was accomplished by four graphite rudders placed in the muzzle of the combustion chamber, and (once high airspeeds had been attained) by the four air rudders mounted on the rocket tail.