RECOGNIZING THE THREAT

In the absence of hard knowledge, the Allies did not begin to respond to the threat of the V–1 and V–2 programs until the summer of 1943. By November 1939, British intelligence knew of the existence of Peenemünde as an experimental station, but they did not know its real purpose. The British Air Ministry’s Scientific Intelligence Office and the British Secret Intelligence Service (SIS) both knew that the Germans were developing some kind of pilotless aircraft and rocket-based artillery. The first information about the nature and extent of the V-weapons appeared in late 1942 and early 1943 from three important sources: disaffected German nationals; foreign nationals who worked with the Germans but maintained contact with members of the Czech, Danish, French, and Polish underground movements; and prisoners of war captured in North Africa. But with each piece of good information on the size, shape, range, and other characteristics of the V-weapons came several pieces of nonsense or exaggeration. By sifting and sorting, the SIS understood that at least one long-range bombardment program was under way, with launching sites probably planned for the Pas de Calais.

In January 1943, the British War Office’s Military Intelligence (MI) branch warned the Central Interpretation Unit (CIU) to watch the French coast for any unusual construction. Meanwhile, SIS asked Britain’s Photographic Reconnaissance Unit (PRU) to look further at Peenemünde. The last available photos of the Baltic station had been taken from a PRU Spitfire in May 1942. New photographic overflights on January 19 and March 1, 1943, revealed that the Germans had constructed many large buildings and a power plant. A conversation overheard on March 22 between two German generals captured in North Africa prompted genuine concern. One of the generals, respected for his technical knowledge, said that he had seen A-series test flights at Kummersdorf. Unaware of the SIS electronic eavesdroppers, he described the rockets, their ballistic flight path, and his doubts that any substantial progress had been made. In light of these comments, MI decided to take evidence of growth at Peenemünde more seriously and alerted operational staffs that the rocket threat might well be real.

On April 11, 1943, after consulting with the scientific adviser to the Army Council and the controller of projectile development in the Ministry of Supply, the British vice-chief to the Imperial General Staff decided to circulate among the vice-chiefs a paper titled “German Long-range Rocket Development.” The paper contained many inaccuracies; for example, it guessed that the enemy was developing a multistage rocket weighing 9.5 tons, capable of delivering 1,600 pounds of explosive over a range of 130 miles. But the bottom line was that the authors believed that a rocket weapon capable of bombarding London was technologically possible —and was probably in development.

On April 15, the vice-chiefs of staff reported the findings to Prime Minister Churchill, suggesting that he appoint Duncan Sandys to a factfinding task. Sandys, respected for his general technical knowledge and his influence as joint parliamentary secretary to the Ministry of Supply, was also Churchill’s son-in-law. The prime minister, delighted with the suggestion, made the appointment quickly and charged Sandys to find out whether the available intelligence was reliable and, if so, to describe the weapon and its delivery system and to recommend appropriate countermeasures.

Sandys immediately asked both the Secret Intelligence Service and the Combined Services Detailed Interrogation Centre to conduct a general investigation, codenamed BODYLINE. He requested that the Photographic Reconnaissance Unit continue to photograph Peenemünde. The CIU gave highest priority to a search for clues about the new weapons; by the end of April, the CIU had prepared a detailed interpretation of photos of Peenemünde taken over four sorties. The area contained many structures common in factory production of explosives, but there were also towers, cranes, and elliptical and circular emplacements that could not be explained. Photos taken over time also revealed movement of very large objects. Overall, the evidence confirmed the expected: Peenemünde was a research and testing facility.

On May 17, 1943, Sandys issued an interim report to the chiefs of staff in which he concluded that the Germans had been busy developing a longrange rocket and that it probably was far advanced. If so, he added, then the British must start studying possible countermeasures and civil defense preparations. Meanwhile, he wrote, the PRU should supply the CIU with more photographs. Overflights on May 14 and May 20 captured disturbing new evidence of cylindrical objects being carried by road and railway. On June 12, photos revealed a tower about forty feet tall and on it a cylinder about thirty-five feet long, blunt at one end and tapered at the other. Finally, on June 28, photographs showed two identical “torpedo-like” items thirty-eight feet long, about six feet in diameter, and each with a tail and three fins. By this time Sandys had no doubt that he was looking at long range rockets.

The BODYLINE investigation moved into its second phase, namely trying to determine some of the specifics of the German rocket program. Working on the assumption that the range of the weapon might be 130 miles, the PRU had photographed the entire area of northern France within 130 air miles of London. The experts looked for “projectors”—tubes or guide rails from which rocket shells would be launched. British scientists and engineers, more familiar with solid-propellant rockets than with liquid-propellant technology, presumed that the German rocket was a two stage, solid-propellant device. Judging from the size of the rockets in the reconnaissance pictures, each one would have to weigh between sixty and one hundred tons, with a warhead weighing two to eight tons. Something that heavy, the experts reasoned, had to be launched from a projection apparatus.

The British experts did not know that the Germans had designed the V–2 to be launched from either fixed or mobile platforms hauled by truck or by railcar. Furthermore, the V–1, which did use a steam-driven catapult as a projection facility, had not yet been deployed. As a result, aerial reconnaissance of France revealed no unusual construction that could be connected to rockets. The lack of evidence was puzzling and cast doubt on how far the enemy rocket program had advanced. And there were other mysteries as well. What evidence was there that the rockets were twostaged? If the rockets used projection launchers, why did they need such large tail fins, components that suggested there were stability problems at launch?

Lord Cherwell, a member of the U.K. Defence Committee and Churchill’s scientific adviser, thought that the rumors of a seventy-ton rocket were nonsense—and he was absolutely correct. However, never imagining that the Germans were using liquid instead of solid propellant, Cherwell concluded that the entire enterprise was a hoax designed to cover some other development project such as a pilotless, jet-propelled aircraft bomb.

The British Air Ministry disagreed with Cherwell. There was too much activity and there were too many related bits of evidence to believe that the rocket program was all a ruse. Rocket experts even retrieved pieces of a V–2 that accidentally fell into Swedish territory during an errant test flight. On June 29, 1943, the Defence Committee decided to strike Peenemünde with a massive Bomber Command night raid as soon as possible. Even Lord Cherwell agreed. Other equally important recommendations made to the Defence Committee included continuing to fly reconnaissance missions along the northern French coast, and preparing to attack any projection installations found there.

The Nazis intended to fire V-weapons against London and cities in southwestern England, including Aldershot, Bristol, Plymouth, Southampton, and Winchester. For the assault on London the Germans needed launching sites for the V–1s and silos or staging depots for the V–2s in the Pas de Calais. For the other targets, facilities would be more to the west, mainly in Normandy. The original plan was to build forty-five V–2 and sixty-four V–1 sites in an arc curving from Cherbourg to St. Omer. The engineers and scientists working in the V–2 program wanted to build concrete bunkers as launch sites, but experienced German officers who knew these bunkers would make obvious targets insisted on the development of mobile launch platforms. As a result, two kinds of V–2 sites were constructed, fixed and mobile. The fixed ones, known as “large sites,” were massive underground structures, possibly intended as launch facilities but definitely used to store liquid oxygen and other supplies. The mobile V–2 launchers, smaller and relatively inconspicuous, could be hauled to a site comprising nothing more than a few sheds. Because the Germans did not start to build V–1 ramps until August 1943, Allied reconnaissance spotted nothing unusual in May or June of that year.

The large sites could not be missed, however. Soon after the Defence Committee’s decision in June 1943 to keep a wary eye on the French coast, PRU sorties began to note strange activity in France at Watten, near St. Omer. Throughout July, as the Royal Air Force (RAF) planned its nighttime raid on Peenemünde, photographic overflights showed that a number of rail lines and huge underground bunkers were being constructed at Watten. Intelligence sources reported that as many as 6,000 construction workers toiled at Watten. Other sources hinted ominously that Watten held an artillery gun capable of firing a shell at a range of 230 miles, that the site held supplies and stockpiles of V-weapons, and that overall headquarters and communications would be located there. British intelligence had heard so many contradictory rumors about the long-range “retaliation” weapons and possible deployment timetables that in late July it turned in desperation to its U.S. and Russian counterparts. The Russians revealed nothing, perhaps because they knew nothing, and U.S. intelligence suggested that Germany intended to use poison gas in its secret weapon program.

Watten was the first of seven large sites. In a July 6, 1943, report to the British Chiefs of Staff, Sandys concluded that the RAF should bomb Watten but that a delay was permissible. The chief of Air Staff, aware that the U.S. Army Air Forces (USAAF) was considering a daylight raid on Watten and Wissant, agreed with the delay. Raids were planned and executed against both sites in mid- to late August. Meanwhile, the CIU noticed that mammoth construction projects had begun at Löttinghen and Wizernes, in September at Mimoyecques and Siracourt, and shortly thereafter at Söttevast and Martinvast on the Cherbourg peninsula. These bunkers had steel-reinforced concrete walls up to thirty feet thick and were large enough to house whole divisions.

Then the Allies detected another kind of site: an elaborate launching platform consisting of two inclined rails, almost 300 feet long, resting on a metal latticework anchored with a concrete emplacement. Intelligence agents in France suggested the British should closely photograph this strange concrete structure near Yvrench-Bois-Carre in the Pas de Calais. Aerial reconnaissance near the end of October 1943 revealed for the first time what came to be know as the “prototype ski site”—a launching platform for a pilotless aircraft bomb. Once the PRU and the CIU knew exactly what to look for, they detected ski sites all around the Pas de Calais. By mid-November, twenty-one such sites had been identified. The Germans eventually completed twenty-two of them and worked on seventy-four more. All of the skis were pointed menacingly at London. Cherwell, who had fought the notion that the Germans had developed a working ballistic missile, was willing to accept the possibility that the enemy had created pilotless aircraft. An Allied aerial offensive against the V-weapons was soon to begin.