Wasserfall was essentially an en.wikipedia.org/wiki/Anti-aircraft development of the en.wikipedia.org/wiki/V2_rocket , sharing the same general layout and shaping. Since the missile had to fly only to the altitudes of the attacking bombers, and needed a far smaller warhead to destroy these, it could be much smaller than the V2, about 1/4 the size. The Wasserfall design also included an additional set of fins located at the middle of the fuselage to provide extra maneuvering capability.Guidance was to be a simple en.wikipedia.org/wiki/Radio_control en.wikipedia.org/wiki/MCLOS system for use against daytime targets, but night-time use was considerably more complex because neither the target nor the missile would be easily visible. For this role a new system known asRheinland was under development. Rheinland used a en.wikipedia.org/wiki/Radar unit for tracking the target and a en.wikipedia.org/wiki/Transponder in the missile for locating it in flight, read by a en.wikipedia.org/wiki/Radio_direction_finder on the ground). A simple en.wikipedia.org/wiki/Analog_computer guided the missile into the tracking radar beam as soon as possible after launch, using the transponder 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 exhaust stream of the combustion chamber, and (once high airspeeds had been attained) by the four air rudders mounted on the rocket tail. The original design had called for a 100 kg warhead, but because of accuracy concerns it was replaced with a much larger one (306 kg) based on a liquid explosive. The idea was to create a large blast area effect amidst the enemy bomber stream, which would conceivably bring down several airplanes for each missile deployed. For daytime use the operator would detonate the warhead by remote control.