In June, 1942, Germany began working on a new secret weapon. It was originally called the Waterfall Rocket (A-4) but was also called Vergeltung (Retribution) as it was built in response to the mass bombing of urban areas in Germany.
British intelligence first became aware of this new weapon when on 22nd August, 1942, a Danish naval officer discovered an early test version that had crash landed on a small island between Germany and Sweden. The officer sent a photograph and a detailed sketch of the bomb to Britain and preparations began to deal with this new weapon that had the potential to win the war for Germany.
With the help of spies and the resistance movement in Germany, British Military Intelligence eventually discovered that the rockets were being built at Peenemünde and in May, 1943, Winston Churchill ordered Operation Crossbow, a plan to destroy rocket production and launch sites. Over the next few months Arthur Harris, head of Bomber Command, arranged for over 36,000 tons of bombs were dropped on these targets.
Ever since the winter of 1939, I had been closely associated with the Peenemunde development centre, although at first all I was doing was meeting its construction needs. I liked mingling with the circle of non-political young scientists and inventors headed by Werner von Braun - twenty-seven years old, purposeful, a man realistically at home in the future. It was extraordinary that so young and untried a team should be allowed to pursue a project costing hundreds of millions of marks and whose realization seemed far away.
My sympathy stood them in good stead when in the late fall of 1939 Hitler crossed the rocket project off his list of urgent undertakings and thus automatically cut off its labour and materials. By tacit agreement with the Army Ordnance Office, I continued to build the Peenemunde installations without its aaproval - a liberty that probably no one but myself could have taken.
On June 13, 1942, the armaments chiefs of the three branches of the armed forces, Field Marshal Milch, Admiral Witzell and General Fromm, flew to Peenemunde with me to witness the first firing of a remote-controlled rocket.
Wisps of vapour showed that the fuel tanks were being filled. At the predetermined second, at first with a faltering motion but then with the roar of an unleashed giant, the rocket rose slowly from its pad, seemed to stand upon its jet of flame for the fraction of a second, then vanished with a howl into the low clouds. Wernher von Braun was beaming. For my part, I was thunderstruck at this technical miracle, at its precision and at the way it seemed to abolish the laws of gravity, so that thirteen tons could be hurtled into the air without any mechanical guidance.
Approximately twenty-five feet long, the Waterfall rocket was capable of carrying approximately six hundred and sixty pounds of explosives along a directional beam up to an altitude of fifty thousand feet.
The A-4 is a measure that can decide the war. And what encouragement to the home front when we attack the English with it. This is the decisive weapon of the war, and what is more it can be produced with relatively small resources. Speer, you must push the A-4 as hard as you can! Whatever labour and materials they need must be supplied instantly. You know I was going to sign the decree for the tank program. But my conclusion now is: Change it around and phase it so that A-4 is put on a par with tank production. But in this project we can use only Germans. God help us if the enemy finds out about this business.
On 22nd August an object had crashed in a turnip field on the island of Bornholm in the Baltic, roughly half-way between Germany and Sweden. It was a small pilotless aircraft bearing the number V83, and it was promptly photographed by the Danish Naval Officer-in-Charge on Bornholm, Lieutenant Commander Hasager Christiansen. He also made a sketch, and noted that the warhead was a dummy made of concrete.
At first, we were not sure what he had found. From his sketch it was about 4 metres long, and it might have been a rather larger version of the HS 293 glider bomb that KG100 was now using against our warships in the Mediterranean. Indeed, it turned out that this particular bomb had been released from a Heinkel III, but it was in fact a research model (the 'V' probably stood for 'Versuchs' i.e. research) of the flying bomb about which we were going to hear so much in the next few months.
Meanwhile the enemy had for years been preparing an attack on England by wholly new weapons. Even before the war we had been warned of the possibility that the Germans were attempting to develop long-range projectiles such as rockets, and in the summer of 1943 the threat was obviously becoming serious and was taken very seriously by the British Government. The Germans had no bombers with which to attack our cities, largely because our area bombing had put the whole German air force on the defensive, but it looked very much as though the Germans were going to develop a very efficient substitute; in fact, their discoveries might well have made all bombers obsolete; there were, for example, quite substantial reports of a rocket weighing 80 tons with a warhead containing ten tons of explosive. In 1943, to raise morale at a time when terrific damage was being done to the German cities, the enemy were uttering a series of threats about new secret weapons to be used against the English; but we had much better information to go upon than this. It was known that these secret weapons were being developed at a particular place, a large research establishment and factory on the shores of the Baltic, at Peenemunde.
On July 7th I held a conference at my headquarters to consider the best method of attacking this objective. It must be remembered that at that time our only successful attacks on single factories in Germany had been made by small forces of exceptionally experienced crews, either in daylight, or, as in the attack on the Heinkel aircraft works at Rostock in the spring of 1942 or in the shuttle attack on the Zeppelin works at Friedrichshafen, when there was an unusually good chance of identifying the target by night. In the attack on Peenemunde, I knew that I should have to use the main force to ensure the destruction of a target of such great strategic importance; and that the attack would have to be made in moonlight; there could be no question of trusting only to H2S for the identification and marking of a target of this nature and Peenemunde was far beyond Oboe range.
Even in moonlight, it would be an extremely difficult task to destroy the whole establishment. Its buildings lay scattered in a narrow strip along the coast line and there was obviously a great risk of wasting most of the bomb load unless some new method of attack was devised; there would clearly have to be several aiming points with different sections of the force assigned fo each of them. It was also known that Peenemunde had a smoke screen and, though the target indicators would show through this and timed runs from a marked position outside the smoke screen would help, the marking itself would be a complicated business.
The tactics eventually adopted were a combination of the normal Pathfinder tactics and those worked out by No. 5 Group for attacks by specially experienced crews. There was, for example, a Master Bomber to assess the accuracy of marking and to give instructions by radio telephone to the whole force; it will be remembered that 5 Group had used this tactic in the previous June in an attack on Friedrichshaven. The main force bombed target indicators dropped by the Pathfinders and were guided by route markers laid by them, but a force of Lancasters from 5 Group were to attack separately in the later stages of the attack, when there was reason to fear that the markers would be obscured by smoke.