In October 1942 Hitler cancelled the A9/10 America-Rocket project. Work was started to increase the range of the V 2 by increasing the efficiency of its fuel and so making it the all-purpose missile.
On 25 October 1942 the Heereswaffenamt issued a contract to the Reichspost laboratory in Berlin to "increase the efficiency of rocket fuels by the application of atomic decay." (A copy of this document appears in the Appendix of Geoffrey Brooks' volume: Hitler's Nuclear Weapons, Pen & Sword Books, 1991.
The success of this project is self-evident from the following four examples taken from postwar publications:
i) SS-Geheimwaffenspezialist Otto Skorzeny stated that the "America-Rocket" was practically ready by the end of March 1945 and would have been in series production from June 1945.
Otto Skorzeny: Meine Kommando-Unternehmen, Universitas, 1993, p.156.
ii) The Washington Post, Los Angeles Times and the British Times newspapers all confirmed the existence of the German intercontinental rocket after the war, and a "manned" rocket with a range of 3,000 miles.
(iii) A NASA Mercury astronaut stated that at the war's end, "a manned V 2" was ready for firing at Peenemünde "with a range of 3,000 miles".
Gordon Cooper: Leap of Faith, Harper Collins, 2000, p.154.
(iv) On 14 June 1945 the British Daily Mail reported on its interview with US Major William Bromley, Assistant Chief of "Special Mission V-2" in which Bromley stated that the "mass production of the V 2 with a range of 3,000 miles would have been possible within 6 months of VE Day (8 May 1945)".
The Bundesarchiv (NS 10/Old 273) has a telegram dated 20 October 1943 from Dr. Kammler to Dr. Brandt, Himmler's scientific adviser, for the information of Reichsführer Himmler, that "today agreement was reached for an underground test base for the development of the America-Rocket "mit der 10-fachen Antriebsstärke", i.e. the rocket for which the efficiency of its fuel had been increased tenfold. The location for the development was caverns in the mountains at Traunstein in Bavaria.
As explained previously, the R-Waffe used a conventional explosive which was detonated simultaneously with an additive to create an environment in which the explosion was increased tenfold. Rocket fuel is an explosive.
Conclusion: A V 2 rocket with small atomic warhead and adulterated fuel for 3,000-mile flight could be safely launched from a Lafferenz barge positioned only 700 miles out from the Norwegian coast so as to hit New York every day until the United States gave in.
For this reason:
"In general it may be said that the Germans were about six months too late in the development and mass production of new weapons".
US Navy Secretary James Forrestal, New York Times, 28 August 1945.
"The Germans were preparing rocket surprises for the whole world in general which would, it is believed, have changed the course of the war if the invasion had been postponed for so short a time as half a year."
Col.Don Leander Putt, Deputy Cmmdg.General AAF Intelligence, Air Technical Services Command: in Harper's Magazine, October 1946, p.329.