Sunday, August 24, 2014
V-2 Rocket, Aggregat 4
The V-2 (German: Vergeltungswaffe 2, "Vengeance Weapon 2"), technical name Aggregat-4 (A4), was the world's first long-range ballistic missile. The liquid-propellant rocket was developed during the Second World War in Germany as a "vengeance weapon", designed to attack Allied cities as a form of retaliation for the ever-increasing Allied bomber effort against German cities. The V-2 rocket was also the first man-made object to enter the fringes of space.
Beginning in September 1944, over 3,000 V-2s were launched by the German Wehrmacht against Allied targets during the war, mostly London and later Antwerp and Liège. According to a BBC documentary in 2011, the attacks resulted in the deaths of an estimated 9,000 civilians and military personnel, while 12,000 forced laborers and concentration camp prisoners were killed producing the weapons.
The V-2's greatest impact may have been after the war; as Germany collapsed, teams from all of the Allied forces raced to collect rockets, designs and the German engineers and scientists involved in the V-2 effort. In the immediate post-war era, these teams were combined with local groups to re-engineer and update the V-2 design. The knowledge gained from these efforts led to rapid progress, especially in the United States and the Soviet Union, and by the mid-1950s, nuclear-armed descendants of V-2 missiles were common battlefield weapons. By the end of the decade these had reached intercontinental range and became a primary strategic weapon.
Through a lengthy sequence of events, a significant portion of the original V-2 team ended up working for the US Army at the Redstone Arsenal. This team, led by Wernher von Braun, would be turned over to NASA on its formation. For NASA they designed a series of booster rockets in the Saturn family, which successfully landed a man on the Moon.
In the late 1920s, a young Wernher von Braun bought a copy of Hermann Oberth's book, Die Rakete zu den Planetenräumen (The Rocket into Interplanetary Spaces). Starting in 1930, he attended the Technical University of Berlin, where he assisted Oberth in liquid-fueled rocket motor tests. Von Braun was working on his doctorate when the Nazi Party gained power in Germany. An artillery captain, Walter Dornberger, arranged an Ordnance Department research grant for von Braun, who from then on worked next to Dornberger's existing solid-fuel rocket test site at Kummersdorf. Von Braun's thesis, Construction, Theoretical, and Experimental Solution to the Problem of the Liquid Propellant Rocket (dated 16 April 1934), was kept classified by the German army and was not published until 1960. By the end of 1934, his group had successfully launched two rockets that reached heights of 2.2 and 3.5 km (1.4 and 2.2 mi).
At the time, Germany was highly interested in American physicist Robert H. Goddard's research. Before 1939, German scientists occasionally contacted Goddard directly with technical questions. Von Braun used Goddard's plans from various journals and incorporated them into the building of the Aggregat (A) series of rockets, named for the German for mechanism or mechanical system.
Following successes at Kummersdorf with the first two Aggregate series rockets, Wernher von Braun and Walter Riedel began thinking of a much larger rocket in the summer of 1936, based on a projected 25-metric-ton-thrust engine.
After the A-4 project was postponed due to unfavourable aerodynamic stability testing of the A-3 in July 1936, von Braun specified the A-4 performance in 1937, and, after an "extensive series of test firings of the A-5" scale test model, using a motor redesigned from the troublesome A-3's by Walter Thiel, A-4 design and construction was ordered c1938/1939. During 28–30 September 1939, Der Tag der Weisheit (English: The Day of Wisdom) conference met at Peenemünde to initiate the funding of university research to solve rocket problems.
By late 1941, the Army Research Center at Peenemünde possessed the technologies essential to the success of the A-4. The four key technologies for the A-4 were large liquid-fuel rocket engines, supersonic aerodynamics, gyroscopic guidance and rudders in jet control. At the time, Adolf Hitler was not particularly impressed by the V-2; he pointed out that it was merely an artillery shell with a longer range and much higher cost.
In early September 1943, von Braun promised the Long-Range Bombardment Commission that the A-4 development was "practically complete/concluded", but even by the middle of 1944, a complete A-4 parts list was still unavailable. Hitler was sufficiently impressed by the enthusiasm of its developers, and needed a "wonder weapon" to maintain German morale, so authorized its deployment in large numbers.
The V-2s were constructed at the Mittelwerk site by prisoners from Mittelbau-Dora, a concentration camp where an estimated 20,000 prisoners died during the war.