Public protests about the noise and danger from the test firings at Kummersdorf meant there was a clear need for a new facility, well away from large populations and with plenty of space for testing larger rockets. In 1935 the decision was taken to find a new, remote location and enquiries began. During the Christmas holidays that followed, Von Braun accepted an invitation to spend some time with friends near the coast of the Baltic Sea. They lived at Anklam, between Stettin and Straslund, by the Peene River. There was an island named Usedom nearby, with just a few inhabitants living on an isolated, rural existence; the Baltic island of Greifswalder Oie lay on the horizon, and beyond that stretched the open Baltic — it was the perfect location for a rocket base. Von Braun reported back to Dörnberger, who asked for more details and later went to inspect the area personally. It was quickly resolved to transfer the research to this new base at the mouth of the Peene River — in German, Peenemünde.
By April 1937 the rocket organization was relocated to its new top-secret base at Peenemünde. This was destined to become the birthplace of modern rocketry, and since 1992 it has been part of the Military Research Centre (Heeresversuchsanstalt Peenemünde) an Anchor Point of the European Route of Industrial Heritage. The staff at the Army Experimental Station at Peenemünde (Heeresversuchsstelle Peenemünde) set out to improve upon the successful A-2 rocket and design a successor, the A-3. The result was a 1,650lb (750kg), 21ft (7m) long rocket burning liquid oxygen and alcohol fuel. By the end of 1937 the Peenemünde team had developed and were ready to test the prototypes. The first failed, and so did the test launches that followed. To the engineers it was obvious that the urgent rush to launch had been too swift. Early problems with the rocket had shown that the tail fins needed to be redesigned; and even when this had been done new problems were emerging. The propulsion system of the A-3 was a success but its inertial guidance system still did not function correctly and further work was initiated to solve this technical problem.
A new approach was needed — in future, every aspect would be bench tested separately and proved to work, prior to being incorporated into the final design. And so a revised policy was drawn up, in the remote vastness of Peenemünde. The German researchers laid their plans, confident that their secret location gave them the chance to make progress, away from prying eyes.
In 1938, Germany began encroaching upon the territory of nearby nations. The occupation of the Sudetenland was at first resisted, but by the end of the year the situation had been accepted by the major powers and Hitler’s expansionism suddenly seemed irresistible. Hitler was encouraged to think again about rocketry and began to recognize the need for an effective ballistic weapon. The Army Ordnance Department decided that the Peenemünde teams should proceed to design a ballistic missile. It should have a range of up to 200 miles (about 320km) and deliver a 1-ton explosive warhead. It was agreed that there were constraints upon the size of the weapon, which would need to fit onto existing railways and move safely through tunnels and cuttings. It would also need to be transportable by truck along existing roadways. The new weapon was designated the A-4, but a more modestly proportioned prototype that could fall between the A-3 and the A-4 was designated the A-5. Although the A-5 was designed to be similar to the A-3, it had a more robust construction and employed a simpler, more reliable guidance system. The A-5 was designed to have the exterior appearance of the proposed A-4 rocket but on a smaller scale.
The excited sense of German expansionism was increasingly apparent to her citizens and the feeling in the research laboratories was one of an expanding future. The advent of war had seemed inevitable for some time so that the actual declaration, announced in London at 11.15am on 3 September 1939, had little effect on the teams. The A-5 tests proceeded and rocket development moved steadily ahead right through 1939. Missiles were successfully fired and many were recovered by parachute and launched again. From the start, the A-5 rockets could reach an altitude of 7.5 miles (12km). The era of the long-range rocket was coming closer by the day. However, for many years, Hitler had seen his military destiny in the invasion and subjugation of nations. His personal preferences were not so much for weapons that descended on a distant enemy from the sky, but for hordes of well-disciplined troops that would occupy and subdue a nation. Hitler had seen his troops walk across great swathes of Europe, he had seen the reports of the successful Blitzkrieg over London, and he again began to be less concerned by rocketry, seeing it as something he might not need after all.
The British were very strong at gathering intelligence and they were already discovering what was happening at Peenemünde. A confidential document on activity there had been sent anonymously to London by a German physicist. This was the so-called ‘Oslo Report’. It was one of the most important documents of its kind ever recorded. Its author was Hans Ferdinand Mayer who earned his doctorate in physics from the University of Heidelberg in 1920. He became Director of the Siemens Communication Research Laboratory in Germany in 1936 and was able to travel widely. He had many contacts across the whole of military research in Germany, and was an inveterate gossip. Most of the flow of information, though, was one-way; and — as Mayer became increasingly concerned about the Nazi threat — he realized that something had to be done to attempt to stem its flow.
The crucial event for Mayer was the invasion of Poland on 1 September 1939 by Nazi troops. Mayer knew the time had come to act, and arranged a business trip to Oslo for the following month. On 30 October 1939 he arrived in Oslo, Norway, and checked in at the Hotel Bristol. He borrowed an office typewriter from the hotel, and over the next few days he started to type out a seven-page document which set down everything he knew about German military plans. It is an astonishing document. On 1 November he mailed the first introductory section to the military authorities in London. If they were interested in the full report, he would send it by mail, he said; confirmation of the British response was to be in the form of a subtle change to the wording of the German-language transmission for the BBC’s overseas service. Mayer said it should begin with the words: ‘Hallo, hier ist London’. He listened to the broadcast, and heard the coded words. Satisfied that his work was wanted, he completed the rest of the report and mailed it to London, along with a sample of a new proximity fuse that he had secretly obtained from Germany.
Mayer was reported to the Nazi authorities as listening to the BBC, and he was accused of uttering anti-Nazi sentiments, so he was arrested by the Gestapo in 1943 and was imprisoned in concentration camps until the war ended; but the Germans never knew about his Oslo Report. Indeed, its very existence was not revealed until 1947. At the end of the war, Mayer was taken to the United States as part of the top-secret Operation Paperclip, intended to give the Americans the benefit of German wartime research. After a time at Cornell University, he returned to Germany, as Director of the Siemens & Halske research department in Munich for communications technology until 1962. He died there in 1980.