The test with a live weapon came on 2 February 1956, with the successful launch of the design for an 80 kT warhead over a 1200 km range - from Kapustin Yar. Area 4N to a point near Priaralsk Karakum, 150 km north-east of the Aral Sea. It was heavily classified that the prototype warhead was a fizzle when it exploded - planned yield was 70 kT, but actual yield was 300 metric tons. The problem was traced to a failed heating element on the warhead.