Rudolph was a farmer's son who received only a basic education, but he had been obsessed with the possibility of space travel from an early age. His career in rocketry began in spring 1930 when he joined the Heylandt factory where Max Valier and Walter Riedel were building rocket-powered cars. Their promising collaboration came to an unfortunate end on 17 May when trials of a modified engine caused a violent explosion. A jagged piece of steel severed Valier's aorta, and the inventor bled to death in Rudolph's arms.
Despite this setback, the team continued to experiment with rocket-engine designs, eventually creating in 1931 an improved version with more efficient fuel injection and the use of fuel as a coolant for the outside of the exhaust nozzle and combustion chamber.
Further progress was halted by the closure of the Heylandt plant. Although unemployed, Rudolph and another ex- Heylandt employee, Alfons Pietsch, began work on an improved rocket assembly. After Pietsch dropped out, Rudolph approached the German Ordnance Department for funding. His new design was successfully demonstrated on 18 August 1934 at the Kummersdorf Army Proving Ground near Berlin.
Even in these early years of the Depression, Rudolph believed that the best hope for a bright future lay with the Nazi party, which he joined in 1931. He later explained, "I read Mein Kampf and agreed with a lot of things in it. Hitler's first six years, until the war started, were really marvellous. Everybody was happy. Everybody got jobs."
Rudolph now joined Germany's rocket experts in an endeavour which would lead to the development of the world's first guided missile. Working alongside him were his former colleague Walter Riedel, and a young engineer, Wernher von Braun. A series of ever more advanced rockets was designed and built at the secret base at Peenemunde on the Baltic coast. Rudolph was given the task of outfitting and managing the giant model shops, preparing the groundwork for eventual mass production of the A-4 rocket (later known as the V-2 or Revenge Weapon 2).
The first successful launch of the new weapon took place on 3 October 1942. Fortunately for the Allies, technical problems and Allied bombing raids prevented the V-2 from becoming operational until 1944. After a successful British bomber attack on Peenemunde in August 1943, construction of the V-2 was shifted to an underground site in Thuringia. Tens of thousands of prisoners were brought from Buchenwald concentration camp to transform a small ammonia mine into a warren of 46 tunnels where the missiles could be assembled in safety. Arthur Rudolph, as the civilian head of V-2 production, was one of the first engineers to arrive at the camp in September 1943.
Over the next two years 20,000 labourers died in the deplorable conditions inside the tunnels at Nordhausen. Forty men died each day from starvation, exhaustion or disease, or were murdered by the SS. The end-product was the launch of 3,000 V-2s on Allied targets, particularly London, between August 1944 and March 1945.
As the war turned against Germany, von Braun's rocket team discussed how they could escape the advancing Red Army. Rudolph was one of 119 rocket engineers who surrendered to the Americans in May 1945. Recognising the value of their captives, the US government secretly shipped them to Fort Bliss, Texas, where they were paid $6 a day tax free, with free medical care, sick leave, accommodation and food. Any previous checks about their war records were ignored.
In return for this privileged treatment, the engineers set about developing America's first long-range missiles. Von Braun's group moved to Huntsville, Alabama, where they built the rockets which would propel men to the Moon. In 1954 Rudolph was granted US citizenship. As one of von Braun's senior lieutenants, he was appointed programme director for the Saturn V, the most powerful rocket ever built.
After the dramatic success of the first Moon landing, Rudolph retired from Nasa in 1969. A grateful government awarded him the Distinguished Service Medal and the Congressional Medal of Honour. Rudolph retired to California, but his Nazi past came back to haunt him. In 1982, Jewish groups began to investigate his war record after Jean Michel, a former inmate of Nordhausen, condemned him in his book Dora: the hell of all the concentration camps (1975; English edition 1979), suggesting that he should have been hanged for his crimes.
Acting on information which had been in their files for almost 40 years, the US Justice Department belatedly accused him of war crimes involving forced labour at Nordhausen. Rather than be charged and put on public trial, Rudolph returned to Germany. On 25 May 1984 he went to the US consulate in Hamburg and renounced his American citizenship but the news did not become public until October that year. He later said that the Justice Department's Office of Special Investigations had pressured him into signing away his precious right to be an American citizen and attempted to re- enter the United States. However, his bid to obtain a visa so that he could participate in the 20th anniversary celebrations of the Apollo 11 landing was rejected.
In 1990, he went to Canada to meet with supporters of his cause, but, after an immigration hearing, he was forced to leave the country. Rudolph claimed that he was unaware of any executions or mistreatment of workers at Nordhausen, and that he tried to obtain extra rations for the workers and improve their conditions. This version was rejected by Jewish investigators, who declared his involvement in a mass hanging of slave workers which took place outside his office.
To the end, Rudolph angrily denounced what he saw as the exploitation and rejection he suffered from the US government. "They only wanted me for what I could do," he said, "and when it was finished they did not care what happened to me."
Arthur Rudolph, rocket scientist: born 9 November 1906; married (one daughter); died Hamburg 1 January 1996.