The aircraft to be used was a Navy version of the Army's B-24 Liberator, reclassified by the Navy as the PB4Y-1. This unusual naval aircraft was powered by four engines that gave it a maximum speed of 300 mph, had a wingspan of 110 feet, and could deliver a payload of 8,000 pounds.
The squadron took heavy casualties while flying missions in the enemy infested Bay of Biscay, but by May 1944 Joe Kennedy had flown his quota of combat missions and was eligible to go home. Instead, he persuaded his crew to remain through June and July, flying more missions as the D-Day invasion took hold in Europe. By the end of July, he felt it was unfair to ask his crew to remain any longer, and they returned to the United States. Kennedy remained, however, and volunteered for a very different kind of mission.
V-2 rockets had been raining down indiscriminately on England, and a daring plan was devised to destroy one of their launch sites in the Normandy area. Lieutenant Kennedy and his co-pilot, Wilford "Bud" Willy, were to fly a Liberator that had been packed with nearly 11 tons of Torpex, a volatile explosive that was nearly twice as powerful as TNT. Two Lockheed Venturas would serve as "mother planes," taking remote radio control of Kennedy's aircraft after he and Willy had armed the explosives and bailed out. The "unmanned air vehicle" would then be steered into a crash dive onto the V-2 site to destroy it.
The mission began at 1800 on 12 August. Filming the mission in a small Mosquito aircraft was the son of the President, Colonel Elliott Roosevelt. He had just recorded some footage showing the pilots in the Liberator's cockpit when a massive explosion hurled debris at the filming aircraft, nearly destroying it. Where the Liberator had been an instant before, there was only a great cloud of smoke and flame with wreckage raining down to the earth below. While several theories were offered for the cause of the explosion—including being triggered by enemy jamming signals—no final conclusions have ever been drawn.
Joseph P. Kennedy Jr., an early pioneer in what has become 21st-century standard technology, was posthumously awarded the Navy Cross. In 1946 the destroyer USS Joseph P. Kennedy Jr. (DD-850) was launched and is today a museum ship at Battleship Cove in Fall River, Massachusetts.