1919 June 28 - Launch Vehicle: V-2.

• Treaty loophole permits German rocket development. Nation: Germany. Signing of Treaty of Versailles disarmed Germany of a military air force but did not include rockets as potential weapons, thus leaving Germany free under international law to develop them. References: 17.

• Die Rakete zu den Planetenräume published. Nation: Germany. Die Rakete zu den Planetenräume (The Rocket Into Interpanetary Space) by Hermann Oberth was published in Germany, and was the genesis for considerable discussion of rocket propulsion. The book would have a huge and life-changing impact on ten year old Wernher Von Braun.References: 17.

• VfR established. Nation: Germany. Johannes Winkler forms the first society for space travel in Breslau. The Society for Space Travel (Verein fuer Raumschiffahrt), is better known by its abbreviation 'VfR'. From the three people that attended the first meeting, it would grow to 500 members within the year, including most of the European space pioneers - Oberth, Hohmann, von Hoefft, von Pirquet, Rynin, and Esnault-Petrie.References: 17.

• Kummersdorf selected for missile development. Nation: Germany. German Army Ordnance Office, after reviewing work of Goddard and others, decided to establish rocket program and to equip artillery proving ground at Kummersdorf to develop military missiles. The German Army issues the first budget for rocket development - 5,000 Reichsmarks.References: 17.

• First liquid rocket hardware developed for the Germany Army. Nation: Germany. Walter Riedel, and Arthur Riedel, at the Heylandt Company, built the first 20 kgf liquid propellant engine for the Heereswaffenamt. It featured a double-walled cylindrical combustion chamber, and was used to test different propellant combinations. References: 693.

• VfR/AIS meeting. Nation: Germany. Raktenflugplatz in Germany was visited by Mr. and Mrs. G. Edward Pendray as official representatives of the American Interplanetary Society, who upon their return organized the experimental program of the society. References: 17.

• Dornberger put in charge of Kummersdorf. Nation: Germany. The German Army Ordnance Office formalized its rocket develoment program by placing Captain-Doctor Walter Dornberger in charge of Research Station West at Kummersdorf. References: 17, 693.

• Von Braun joins German Army missile program. Nation: Germany. Wernher von Braun joined the German Army Ordnance Office rocket program at Kummersdorf. He is working on a 300 kgf thrust liquid propellant engine, which has been tested with an exhaust velocity of 1700 m/s, but it is believed can be tuned up to as much as 1900 m/s. This is to power the A1 rocket, which is to have the same tractor configuration as the 20 kg test rocket launched in August 1932. The main issue is how to solve the problem of keeping the rocket stabilised in flight, as the August test demonstrated. The A1 is to be 1.4 m long x 30 cm in diameter, a 150 kg gross takeoff weight, and 40 kg of propellant., allowing a 16.5 second burn time.References: 17.

• Private rocket development in Germany winds down Nation: Germany. As the influence of Nazism in German Society increases, the VfR disintegrates in political disputes and withdrawal of funding by its wealthiest backers. In this period it occurs to Riedel that alcohol may prove a better fuel than gasoline - primarily because as a fuel it needs much less of the expensive and difficult-to-handle cryogenic liquid oxygen. Experiments determine that 60% alcohol to water is the best fuel mixture, and for the first time use the fuel to cool the combustion chamber before leading it into the chamber - regenerative cooling.References: 47.

• Rocket test stand explosion at Kummersdorf. Nation: Germany. No one was injured and more stringent safety precautions were taken in the future. References: 693.

• Liquid rocket explosion kills three. Nation: Germany. Dr Kurt Wahmke and two technicians were testing a 90% H2O2/Alcohol combination at Kummersdorf when the chamber exploded, killing them. These were the first and only deaths of technicians in the history of German rocket development. References: 693.

• Go-ahead to build Peenemuende Nation: Germany. The missile test range is to be a combined Army / Air Force test ground. Von Braun had found the location in December 1935, after his first choice - Briz on the island of Ruegen - was taken over by the Deutsch Arbeitsfront as a 'Kraft durch Freude' recreation camp. During his Christmas holiday, Von Braun toured the cost, and found Peenemuende. It seemed perfect - 400 km of ocean to the east for use as a missile shooting range, room along the path on the coast for tracking radars.References: 693.

• A4 wind tunnel tests Nation: Germany. The tests showed that the A3 configuration was unstable in flight and that it was going to take a lot of trial and error to identify the correct aerodynamic shape for the supersonic missile. Therefore the decision was taken to go slow on development of the A4 until tests with the A3 were complete. The 25 tonne thrust engine would also have to be built and proven in ground tests to determine its actual characteristics before a lot of effort was put into final design and construction of the rest of the rocket. So a series of test launches of the A3 to test the A4 control and guidance systems were undertaken, while Test Stand I at Peenemuende was prepared for tests of the 25 tonne engine.References: 693.

• Ground broken at Peenemuende Nation: Germany. First objective is development of the A4 strategic ballistic missile, later dubbed the V-2. The missile is to deliver a one tonne high explosive payload to double the range of the Paris Gun of World War I (250 km - the Paris Gun could deliver a ten kg, 21 cm diameter shell to 125 km range). To provide a reserve, the missile was designed for a 1500 m/s burnout velocity, which resulted in a 275 km range. Accuracy was to be 2 to 3 per mille, versus typical artillery shell accuracy of 4 to 5 per mille. These requirements indicated a 25 tonne thrust engine, powering a 12 tonne missile, with a 2100 m/s exhaust velocity, burning 8 tonnes of propellant in 65 seconds. The requirement to transport the missile by rail limited the diameter to 1.6 m, which in turn led to a 14 m length. Span with the detachable tail fins was 3.5 m.

  Several major issues had to be solved during development. The first was what wing and body shapes would be stable at supersonic velocities. Another was building adequate ground facilities for the intensive tests needed to develop the 25 tonne thrust motor. For this purpose a static test facility was built at Peenemuende capable of handling 100 tonne thrust motors, seen as the next step after the A4. Another major problem was developing high-capacity pumps to deliver the liquid oxygen at a temperature of -185 deg C.References: 693.

• First supersonic wind tunnel. Nation: Germany. Following problems with testing of the A3 (a subscale version of the planned V-2) by Dr Hermann, Von Braun proposes to the Germany army that a supersonic wind tunnel be constructed at a cost he estimates as 300,000 Marks. Other parts of the Army are not supportive of the facility, but it is finally built, costing millions more than Von Braun estimated.References: 693.

• Peenemünde opened. Nation: Germany. Joint German Army-Air Force rocket research station opened at Peenemünde on the Baltic Sea. The Army Ordnance rocket program under Capt. Walter Dornberger moved 90 of its staff from Kummersdorf. Thiel and five staff working on V-2 rocket engine development remained at Kummersdorf until the summer of 1940, when the test stands at Peenemuende were finally completed..References: 17, 693.

• A4 engine tests begin Nation: Germany. The engine delivered 18 months after design started was so compact, that the length of the A4 could be cut in half. Walter Thiel, a gifted and systematic researcher, was responsible for the engine design. He had great difficulties in obtaining stable combustion, and preventing burn-through of the chamber walls. Various injector patterns were studied in a 1.5 tonne thrust chamber. His research finally reduced the combustion chamber length from 2 m to 30 cm, while the exhaust velocity was increased from 2000 m/s to 2100 m/s, and eventually reached 2280 m/s. However the reduction in the cooling area of the chamber also increased problems in preventing hot spots and burn through. This was finally solved by using a conical throat exit and a mixing chamber ahead of the burning chamber. The 1.5 tonne thrust engine was initially run at 15 bar pressure, versus the 50 bar desired. But whenever the combustion chamber pressure was increased, burn-throughs occurred, as well as forcing increases in the mass of the pumps and tanks. Therefore finally the decision was taken to leave the chamber pressure at 15 bar.

  The next step was to make a 4.5 tonne thrust by clustering three of the 1.5 tonne engines as preburners. However Thiel still had burn-throughs in test runs. Poehlmann suggested the use of film cooling, which finally solved the problem. For the 25 tonne thrust engine, Thiel simply used 18 x 1.5 tonne thrust chambers, feeding a common mixing chamber. This was on the test stand in early 1939.References: 693.

• A5 delivered to Peenemuende. Nation: Germany. The first A5 drop test model is delivered to Peenemuende just weeks after the third A3 test. Production is planned at a rate of 10 per month to define the A4 aerodynamic configuration. Objective of the first tests is to break the sound barrier - in the wind tunnel no configuration of fins had managed to go through the barrier without disintegrating. The only test possibility was to drop the model from a great height, and let gravity accelerate it to supersonic speeds. The model weighs 250 kg and is 1.6 m long and 20 cm in diameter.References: 693.

• Rocket fighters Nation: Germany. Spacecraft: He-176, He-122, Me-163. The first rocket fighter, the He-176, powered by a Walther engine, was tested at Peenemuende. In competition, Dornberger's team developed a 120-second duration engine to power the He-122. However loss of control in unpowered flights of the latter resulted in it crashing and being eliminated from further consideration. Dornberger's team left further rocket fighter engine development to Walther, and concentrated on the A4 and follow-on ballistic missiles.References: 693.

• First A5 drop test. Nation: Germany. The model is dropped from a He-111 bomber from 7000 m. It breaks through the sound barrier at 1000 m altitude at a speed of 360 m/s. The stabilising fins keep the maximum oscillation of the model to within 5 degrees from vertical. The drogue ring parachute then deployed to decelerate the model to 100 m/s, followed by the main parachute which slows it to 5 m/s when it impacts in the ocean.References: 693.

• A5 stabilisation system tests Nation: Germany. In order to test the A4's stabilisation system, Walter, Kiel, is subcontracted to build a large number of model A5's. Like the drop test models, these are 20 cm and 1.6 m long. However they weigh only 47 kg gross lift-off mass, with a 27 kg empty mass. The rocket engine burns 85% hydrogen peroxide monopropellant using a calcium permanganate catalyst. The engine produces 120 kgf for 15 seconds, and has an exhaust velocity of 1000 m/s. The design objective is a low cost, reliable, and simple rocket, which will allow a large number of trail-and-error test launches to be made within a tight budget. The fins developed for the A4 as a result of these tests were shorter and wider than those of the A3. They owed nothing to aircraft wing designs of the times, which couldn't withstand supersonic speeds. But they were still too affected by the wind, tending to set the rocket on a rotation around its long axis during ascent.References: 693.

• Hitler visits Kummersdorf-West Nation: Germany. This was the first time he became acquainted with liquid rocket engine technology. 300 kgf and 1000 kgf engines were fired in his presence. A colour-coded cutaway model of the A3 rocket was presented and its systems explained. Hitler was quiet throughout the exhibits and asked no questions. Afterwards, while taking lunch at the mess hall, he asked only about the development schedule (clucking when told), the range of the missile, and the impact on the schedule if synthetic 'Eisenbled' was substituted for light metal alloys in the rocket frame. Hitler spoke of deceased rocket pioneer Max Valier - he had known him in Munich, but dismissed him as a dreamer. Dornberger countered by comparing the state of rocket development to the early days of the zeppelin, when Lillienthal made the first primitive experiments. Hitler in turn dismissed airships as dangerous, filled with explosive gas . The Fuehrer finally departed with handshakes and few words. His summary of the day: 'Es war doch gewaltig' (it was impressive, nevertheless). The rocket team was dismayed - it was the first time a visitor had exhibited no reaction to the power the rocket engines when fired for their benefit. But on the plus side, Von Brauchtisch said he was astounded at the progress made by the team in only a few years. Dornberger believed Hitler was enthralled with artillery and tanks, and was unimpressed with rocket technology. He thought Hitler didn't understand the possibilities and didn't believe the time had come yet for development of the rocket as a weapon.References: 693.

• A4 in crisis Nation: Germany. After Hitler's visit, it finally it became clear to Dornberger that either support for the project would have to come from the highest level, or that Peenemuende should abandon rocket research and be devoted to more pressing war needs.

  Meanwhile the results of the air war over London showed that the A4 could be an economic weapon. Bombers were averaging only 5 to 6 missions, dropping only 6 to 8 tonnes of bombs before being shot down. Once the loss of trained flying crews was considered, the bomber cost 30 times more than the A4 to deliver a tonne of explosives on London compared to the expendable A4 at its production price of 38,000 Marks. But time was being lost in convincing others in the German leadership that the missile should be put into production.References: 693.

• A4 full scale development authorised Nation: Germany. Von Brauchtisch gave the go-ahead for the A4 to enter full development as a weapon system for the German Army. References: 693.

• Goering tours Kummersdorf-West Nation: Germany. Unlike Hitler, he was enthusiastic about the potential of rocket technology. References: 693.

• Rocket development given highest priority Nation: Germany. Von Brauchtisch obtained the highest priority for development of the A4. This was used in early 1940 to get 4,000 soldiers with the necessary engineering and technical backgrounds released from the Army and sent to Peenemuende's 'Versuchskommando-Nord'. Nevertheless there was a constant fight for priority in obtaining materials.References: 693.

• Second functional A5 launch. Nation: Germany. Apogee: 7.00 km (4.30 mi). This was a vertical launch, replicating the first launch of the series, and was again recovered successfully. References: 693.

• Third functional A5 launch. Nation: Germany. Apogee: 4.00 km (2.40 mi). This was the first test of the pitch-over manoeuvre required for the operational A4. The test went perfectly - the rocket pitched over 4 seconds after lift-off, reaching 4 km altitude, and was 6 km downrange from the launch point when the drogue parachute deployed. The rocket was recovered from the ocean successfully. This was finally a complete success after seven years of developmental effort. But the rocket had not broken the sound barrier.References: 693.

• Further A5 test launches. Nation: Germany. Apogee: 18 km (11 mi). The German rocket team successfully fired and recovered further A5 development rockets with gyroscopic controls and parachutes, attaining altitude of 12 km and a range of 18 km. References: 693.

• A9 basic research and design Nation: Germany. By adding wings to the A4, the 800 m/s of kinetic energy the rocket had at cut-off could be exploited in a glide attack, extending the range of the missile from 250 km to 550 km. Such a supersonic aircraft had never been flown and presented many aerodynamic and engineering problems in 1943. Various tests of the A4's with wings began in early 1940. These were successful, and the configuration was dubbed the A9. The trajectory for such a missile involved a boost to an apogee of 29 km, then a stable glide at 20 km altitude at a speed of 1250 m/s. At the end of the glide, the missile would have descended to 5 km altitude, then make a vertical dive on the target in the fashion of the Fi-103/V-1. The A9 would be equipped with wings with a total area of 13.5 sq m. A manned version of this boost-glide rocketplane was also designed. This could reach a conventional airfield 600 km from the launch point in only 17 minutes, landing at a speed of 160 kph. Another possibility to further extend range would be a catapult-launched A9, using the technology developed for the V-1. This would provide an extra velocity of 350 m/s, further extending the missile's potential range.References: 693.

• Peenemuende wind tunnel goes into operation. Nation: Germany. The tunnel was used an average of 500 hours per month. 1000 cubic metres of vacuum vessels were pumped to a 98% vacuum in three to five minutes by three banks of double vacuum pumps. When vented, they provided the tunnel with 20 seconds of run time at velocities from Mach 1.2 to Mach 4.0, or 1500 m/s. Models 4 to 5 cm in diameter x 30-40 cm long could be accommodated in the tunnel, instrumented at 110 data points. These tests showed that drag increased 70% at the sound barrier and that the centre of pressure on the missile moved back one-half calibre. The wind tunnel runs showed that the basic A4 shape was all right, but that it needed load-carrying wings and a new rudder for the higher-speed A9 glider version. Huge trial and error was required to develop an A9 configuration that was stable, but not so stable that the control surfaces were too large. An arrow wing was the best performing, but the control surfaces were then in the turbulent flow of the wing and inadequate. Swept wings provided 12% less glide ratio than the arrow wing, resulting in a 60 km loss of range. Trapezoidal wings were the final solution, the end of a long iterative process.

  Peenemuende-developed delta wings were adapted to Army artillery rounds of the 105 mm flak gun and K5 280 mm cannon, decreasing drag by 35%. The result was an increase of 6 kg in the explosive load, a 6 kg increase in the iron mass of the round, but with a range increase from 59 to 90 km. Equipped with a new, lighter warhead, and a sabot boosting a slimmer round, the gun could shoot projectiles to a range of 135 to 150 km, with an accuracy of 2 per mill.References: 693.

• A4 radio guidance tests Nation: Germany. In early 1940 a Do-17M aircraft was equipped with a Siemens fully automatic autopilot. This was designed to keep the aircraft within a 50 mhz guidance beam, which was produced at a 3 kW transmitter installed at Bornholm Island in Denmark, northeast of Peenemuende. The aircraft would capture the beam b flying within 1 degree of the its centre at a distance of 2 km from the transmitter. After a 140 km flight the aircraft would still be within 20 m of the correct position. The beam had a total effective range of 200 km. The Peenemuende team remembered its accuracy by the fact that on each test they would always fly over the same small red house in Bornholm on the coast.

  Use of the system on the A4 was complicated by the problem of the electrical charge that formed on the rocket body during flight through the atmosphere, and the electrical ions in the rocket exhaust, both of which made good reception of radio signals difficult. 90% of a 50 mhz signal was attenuated at the critical moment of engine cut-off. Another accuracy issue was oscillation of the rocket once it was out of the atmosphere - the rudders in the exhaust did not act smoothly, producing the equivalent of pilot-induced oscillations. The solution was to develop a missile that rode the beam during the entire boost phase, not just converging with it at the point of engine cut-off.

  Many partial system test stands were used to solve these control and guidance problems, most notably a full-up 'iron bird' that could be used to test the effect of new systems on existing components.References: 693.

• A4 rocket development removed from priority list. Nation: Germany. After the military success in Poland, Hitler believes development of expensive 'wonder weapons' are unnecessary to win the war. The A4 and other rocket projects are removed from the priority list, making acquisition of necessary materials and engineers difficult.References: 394.

• First full-duration test of A4 engine. Nation: Germany. The engine is run at 25 tonnes thrust for 60 seconds on Test Stand I at Peenemuende. References: 394.

• Peenemuende test stands completed. Nation: Germany. Thiel and the remaining staff of the rocket team at Kummersdorf moved to Peenemuende. References: 693.

• A4 engine improvements Nation: Germany. Throughout the early 1940's Thiel and his team sought to produce a single chamber 25 tonne thrust engine in place of the kludged prototype engine that used 18 separate 1.5 tf chambers. They managed to demonstrate a 60 second burn time in the 18-chamber design, but the engine itself was considered too complicated to fabricate in production, requiring thousands of hand-assembled tubes to introduce fuel and oxidiser into the chamber. Thiel sought to replace these thousands of tubes with a simpler injection system - rows of simple bored holes on a flat injector plate at the head of the chamber. Beck at the Technische Hochschule in Dresden developed a ring-pattern injector that worked well in subscale engines. But the design proved unstable in the 25 tf engine. Therefore, it was decided to stick with the 18-head chamber for V-2 production.References: 693.

• A4 facilities Nation: Germany. The A4 assembly hall at Area 7 at Peenemuende was 30 m high and 50 m long. After assembly, the missile was moved to the cold flow test stand. There each rocket was tested and calibration documents were generated, necessary for the launch troops to take into account when preparing the rocket and programming its guidance system. The launch pad itself was ringed by a 7 m wide concrete embankment, and sunk 6 m into the ground. The viewpoint was 150 m from the pad, at the southern, smaller end of the complex.

  The pad was surrounded by instrumentation rooms. Water was delivered at 500 litres/second through a 1.20 m diameter pipe to a molybdenum steel cooling section, consisting of many pipes running around the exhaust blast diverter. Other test stands included number 10, where the effects of the rocket exhaust on different material surfaces was tested; and number 8, where newly delivered engines were fired and calibrated. These certification tests ran as long as 650 seconds on the water-cooled stand. Area 9 was used for launches of the Wasserfall surface-to-air missile, and Area 2 for tests of the A4 using nitric acid and Visol as propellants. Area 4 was devoted to firing tests of engines installed in aircraft fuselages, and Area 3 contained the 1000 kgf engine test stand. This stand included pump and steam test stands, and a hydrogen peroxide plant. Area 6 was built to the same design as the largest test stands at Kummersdorf, and used for A5 tests. Hundreds of A5's were shot from Greifswalder Oie.References: 693.

• Full-scale development of A4 authorised. Nation: Germany. Following the loss of the air war with Britain, the German military leadership realises that missiles offer the only possibility of attacking London. Development of the A4 to the point of production-readiness is authorised. References: 394.

• Mach 10 wind tunnel designed. Nation: Germany. In preparation for the A9/A10 transatlantic missile, the Peenemuende team completed design of a Mach 10 wind tunnel. However construction would not begin for another two years due to priority on devoting all available engineering time to getting the A4 into production.References: 693.

• A4 series production Nation: Germany. An initial series of prototypes were built at the factories of Dip-Ing Stahlknecht, then a second line was opened up at Dr Eckener's Zeppelinwerke. References: 693.

• V-2 s/n 1 moved to Test Stand VII at Peenemuende. Nation: Germany. The missile was used for facility checks and checking of launch procedures. References: 394.

• V-2 s/n 1 explodes during engine test run. Nation: Germany. The missile was being tested on Test Stand VII; no launch had been planned. G Harry Stine noticed that the German rocket scientists at White Sands were very reluctant to talk about the details of the failure, but finally managed to get the real story from Konrad Dannenberg:

  The first A.4 missile was a hand-made job. Motor tests preceding the first flight were to be carried out in a huge, mobile test stand, which held the entire missile. However, this first A.4 never flew; it found its end in the test stand. In order to clamp the missile into the stand without attaching the thrust mounts to the missile structure, a large steel corset was built. Unfortunately, the builders of this corset did not take into account the shrinkage of the missile components when the frigid liquid oxygen was pumped aboard. The first A4 shrank, dropped out of the corset, and was a total wash-out.

  The test was to have examined the behavior of the guidance system and the graphite steering vanes in the exhaust flow. The corset had pivot mountings on it to allow the missile to be deflected while its motor was being fired, to see how fast the steering vanes responded, and what amount of corrective force they developed. After the failure, the Peenemuende team was embarrassed by the fact that they had overlooked something as obvious as the fact that cold things shrink.References: 394.

• A4 reliability development Nation: Germany. The early failure rate of the A4 prototype missiles was extremely high, so the Peenemuende rocket team had to develop new measures to test and improve reliability down to the component level. This included improved quality control during manufacture, and test of the missile's components in all weathers, not just in heated laboratories. This resulted in the overall missile failure rate declining from 17% in the early test series to 4% in the final series. The V-1/Fi-103 cruise missile had a 28% higher failure rate, even though it was a simpler design.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 1.00 km (0.60 mi). First test of the German A-4 (V-2) rocket unsuccessful at Peenemünde, Germany. The missile never guided correctly, and crashed 1.3 km from the pad after 36 seconds of powered flight. References: 17, 771.

• Submarine launch of powder rockets Nation: Germany. Solid propellant rockets were fired from a submerged platform off Greifswalder Oie to test the concept of a submarine-launched missile. The idea came from Steihoff, an engineer on the rocket team whose brother was a submarine captain. 20 to 30 Wurfgeraete of the Army's smoke corps, equipped with flammable oil or explosive warheads, were shot at the coast from up to 3 km away. The concept was to put enemy coastal oil storage tanks into flames. At Swinemuende a launcher was installed aboard a Submarine and salvoes of 20 rockets successfully fired from 10 to 15 m under water. The launcher was unnoticeable on the submarine, and the dispersion of the rockets was only a bit worse than a shot from land. But the German Navy wouldn't accept simply using an existing Army launcher. They insisted on developing a different one themselves, which would take a year, putting deployment of the system beyond the end of the war.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 11 km (6 mi). Engine burned for 45 seconds and total flight time was 194 seconds. References: 769.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 48 km (29 mi). First successful launch and flight of 5 tonne German A-4 rocket (V-2) at Peenemünde, which traveled 190 km. The engine burned for 58 seconds, and total flight time was 296 seconds. The missile impacted 6 degrees left of the intended course. References: 17, 769.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 40 km (24 mi). The steam generator was seen to vent from T+66 to T+88 seconds. The engine burned for 84 seconds, and total flight time was 250 seconds. The missile impacted 3 degrees left of the intended course. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 67 km (41 mi). Vertical shot to test systems. The engine burned for 54 seconds, and total flight time was 273 seconds. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 5.00 km (3.10 mi). The engine burned for 37 seconds, and total flight was 171 seconds. References: 950.

• Peenemuende team's spaceflight plans Nation: Germany. Using catapults and wings an A9 might nearly achieve 1000 km range, but the only solution for transatlantic missions was the two-stage A9/A10. The A10 boost stage was to have a total mass of 87 tonnes, of which 62 tonnes would be propellant. The stage's 200 tonne thrust motor would burn for 50 to 60 seconds, taking the A9 upper stage to 1200 m/s. Then the A9 would separate and burn its engine, reaching an apogee of 55 km, followed by a long hypersonic glide in the atmosphere. The second stage would be equipped with air brakes for deceleration over the target, followed by a parachute for recovery in the water. The A9/A10 would reach a maximum velocity of 2800 m/s, and have a range of 4100 km, and a total flight time of 35 minutes. Full-scale development was underway, when further significant work on the project was stopped at the end of 1942. Only the Advanced Projects Group, under the direction of Dip-Ing Roth and Ing Palt, continued design of the missile. It was also planned to develop, after the war, a stratospheric rocket that could travel in 40 minutes from Europe to America. After that, the target was orbital spaceships that could reach 8 km/sec and 500 km orbital altitude. Beyond that, space stations and the burial in space of the embalmed bodies of the rocket developers and men of the rocket service. Manned expeditions to the moon were also a popular theme for research. Finally, the use of nuclear energy to achieve interstellar travel was studied by the Advanced Projects Group.References: 693.

• A4 priority Nation: Germany. Dornberger clashes with Speer over priority for the A4. References: 693.

• Train-launched A4. Nation: Germany. A rail-launched A4 was considered from the beginning of the project. At the end of 1942 the first train launcher wagon was completed and trials began from Test Stand VII at Peenemuende. In service the trains would have hidden in double-tracked train tunnels. Development was interrupted to get the vehicle-towed standard version of the weapon into service.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. The engine burned for 4 seconds before the missile exploded 100 m from the pad. References: 950.

• A4 guidance development Nation: Germany. Using its original gyroscopic guidance package, the A4 demonstrated a 4.5 km CEP up to 1943, with 100% of the shots falling within 18 km of the target. Many factors contributed to this inaccuracy - out of tolerance guidance system components, and poor alignment of the gyro platform prior to firing. One solution developed was a radio correction system similar to that used by aircraft for landings in poor visibility. A moving radio beam would follow the correct course, and the rocket would manoeuvre to stay within the beam. But there was no support within the Army for full development of such a system - their priority was in developing and deploying distance-measuring radio navigation systems for the aviation forces. A radio guidance unit was not used aboard an A4 until near the war's end, and that used an adaptation of a system designed for a beam-riding air-launched missile. But even using the radio correction technique, the engineers were unable to get the rocket's CEP under 2 km.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Missile exploded at ignition. References: 950.

• Showdown meeting on A4 Nation: Germany. Speer meets with Von Braun and Dornberger. A 1:100 model of the planned bunker construction-launch facility for the rocket to be built by Organisation Todt on the British channel was exhibited. Speer reveals that Hitler could not decide about the rocket as a weapon. He did not believe the rocket team's plans could be made to work. But Speer did authorise them to proceed with construction on his own authority - he hoped Hitler could be brought around eventually. But he emphasised that Dornberger would have to use his personal connections to get industry moving on the project. But Dornberger was thwarted when the Army put Degenkolb in charge of organising production of the missile. Degenkolb was a sworn enemy of Dornberger's, and had been implicated in the 'suicide' of General Becker in early 1940. Degenkolb set up a Nazi-supported bureaucracy in parallel to that of Dornberger's, requiring the approval of the Army weapons bureau on any decisions. Degenkolb had the sponsorship of Todt and Saur, who in turn followed the party line - 'like the Fuehrer, we are not yet won over to the concept of a long range missile'.

  In order to productionise the A4 design, Degenkolb began authorising many detailed changes. He didn't understand that every change had to be proven in test first, and only incremental steps could be taken. Stahlknecht had planned to produce 300 A4 missiles per month by January 1944, and 600 per month by July 1944. Degenkolb unrealistically decreed that 300 per month be achieved by October 1943, and 900 per month by December 1943.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 40 km (24 mi). Trajectory too steep, and the missile rolled in flight. The engine burned for 64.5 seconds, and total flight was 278 seconds. The missile impacted 7 km left of the intended course. References: 950.

• Peenemuende privatisation Nation: Germany. In a meeting with Professor Hettlage, of the Financial and Organisational Ministry of the German Defence Industry, it was proposed that Peenemuende be made a private country, with the Nazi Party and selected corporations (AEG, Siemens, Lorenz, Rheinmetall) being its shareholders. Dornberger saw Degenkolb behind this plan, and was determined to keep Peenemuende an Army proving ground. He felt that an asset, on which several hundred million Marks had been invested by the government, was being handed over to private hands for 1 to 2 million Marks. The investors intended to recover their entire investment back on a fee paid for each missile built. In the end Dornberger managed to keep Peenemuende an Army proving ground, but then he had to fight off an attempt by AEG to take over the electronics side of the development team. The rocket team's electronic engineers were years ahead of the rest of the industry, and a tempting target.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 30 km (18 mi). Trajectory too shallow. German A-4 (V-2) rocket traveled 196 km after launch from Peenemünde. The engine burned for 62 seconds, and total flight was 243 seconds. The missile impacted 1 km right of the intended course. References: 17, 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 1.00 km (0.60 mi). The missile traveled backwards, crashing 4.8 km inland from the pad. Burn time was 1.8 seconds, flight time 5.2 seconds, and the missile landed 163 degrees off the intended trajectory. References: 950.

• A4 production plans Nation: Germany. A4 missiles were to be produced at Peenemuende, Friedrichshafen, and the Raxwerken at Wiener Neustadt. But problems began immediately - the Army expected the rockets to be as easy to build as locomotives; there was no engineering staff or time available to productionise the prototype design; there were no staff available to properly train production engineers and technicians. Degenkolb threatened to imprison the rocket team's engineers if they didn't get the missile into production on schedule. He was oblivious to the difficulties of achieving this.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Vertical flight interrupted by an explosion in the aft compartment. The engine burned for 33 seconds, and total flight was 128 seconds. References: 950.

• Hitler's dream Nation: Germany. Hitler dreamed that no A4 missile could ever reach England. The result was that the program lost its priority amidst other pressing armaments programs, and the necessary engineers and production rocket engines could not be obtained. While losing priority, the high security classification remained, so it was not possible to recruit non-German engineers and technicians for the work. The production schedule inevitably slid. Finally the government decided to competitively evaluate the Fi-103 cruise missile (V-1) against the A4 ballistic missile (V-2) leading to the selection of a single weapon for mass production by July of 1943.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). Trajectory too steep, the rocket rolled in flight. The engine burned for 60 seconds, and total flight was 268 seconds. The missile impacted 12 km right of the intended course. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Staggering rotation of the rocket in flight, vertical flight, ending in an explosion. The engine burned for 28 seconds, and total flight was 102 seconds. References: 950.

• Himmler visits Peenemuende Nation: Germany. This was the first review of the facilities by the SS commander. He pledged support, but instead the SS set up its own rocket research centre at Grossendorf, near Danzig. This marked yet another struggle for control of the programme. Himmler was defeated in this effort, but he would take his revenge later.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). The missile impacted on land, 38 km right of the intended course. The engine burned for 66 seconds, and total flight was 320 seconds. References: 950.

• V-2 development detected by British Intelligence. Nation: Germany. Prime Minister Winston Churchill of England was informed of reports on German experiments with long-range rockets. References: 17.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). The missile impacted on land, 22 km right of the intended course. The engine burned for 59 seconds, and total flight was 310 seconds. References: 741.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). Cut-off mechanism disabled and missile allowed to burn to fuel depletion. The engine burned for 62 seconds, and total flight was 315 seconds. The missile impacted 900 m right and 20 km beyond the aimpoint. References: 950.

• V-1/V-2 fly-off Nation: Germany. A government commission, consisting of Speer, Milch, Doenitz, and Fromm viewed launches of the competing missiles at Peenemuende. The V-1/Fi-103 was much cheaper than the V-2/A4, but it was slow and low - it operated at 160 m/s at an altitude of between 200 and 2000 m - and vulnerable to enemy flak batteries and interceptors. It provided the enemy with a forewarning of attack by its characteristic engine noise and the cut-off of that noise when it went into its terminal dive. It could only be launched from fixed concrete launch ramps, making the launchers vulnerable to enemy air attack. The V-2 was mobile, more accurate, could not be intercepted, and gave the enemy no warning of attack in its supersonic ballistic course to the target. In the end, the commission could find no overwhelming advantage to either of the very different weapons, and both were ordered into production. The positive advantages of each weapon outweighed the negatives. In the tests before the commission, the Fi-103 had bad luck, and achieved no successful shots for two of the A4. '2:0 for your team', Milch told Dornberger. Speer claimed he 'always supported' the A4 but Dornberger ruefully noted they had lost 18 months in delays, primarily due to Degenkolb's incompetence. Speer pressed Dornberger - if Degenkolb really can't make it happen, then just give me the word. He'll be dismissed. But Degenkolb was not dismissed - he had Saur's complete backing.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). Test of the engine cut-off mechanism. The engine burned for 66.5 seconds, and total flight time was 349 seconds. The missile impacted 7 km right and 5 km beyond the aimpoint. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 10 km (6 mi). Test of the early cut-off mechanism and engine control. The engine burned for 40 seconds, and total flight time was 200 seconds. The missile impacted 0.3 km left of the intended trajectory. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). The engine burned for 55 seconds, and total flight time was 248 seconds. The missile impacted 1.6 km right and 9 km beyond the aimpoint. References: 950.

• Dornberger promoted Nation: Germany. Dornberger was promoted to Major General. But Degenkolb was still in charge of A4 production, and had sent four engineers to spy at Peenemuende, asking them to provide recommendations on reorganisation of the place, promising the four that they would be made directors of the new enterprise.References: 693.

• V-2 firing range to be established in Poland. Nation: Germany. It is decided to move testing of production V-2s and training of combat launch crews from the Baltic Sea to the middle of Poland, at Heidelager, near Blizna. German units here operationally test fired over 100 V-2's, launching 10 on one day, only a small number of which were fully successful.References: 17.

• A4 development Nation: Germany. Area 7 was used for tests of the A4's pyrotechnic igniters. The missile could be ordered to cut off its engine by radio if it veered inland. Delays in development were inevitable - a 'Peenemuende Minute' corresponded to 11 minutes or more on the watch. On one memorable occasion, the missile ignited, but its fuel pump did not reach full speed. The rocket reached only 4.5 m altitude before hovering, its abnormally low thrust exactly counterbalancing the mass of the missile. The film operator kept his post, only 100 m from the fantastic sight. As the rocket consumed propellant, its weight was reduced, and it slowly moved skyward, reaching 10 m, then 22 m, and slowly drifting out of the launch pad area. It finally crashed only 40 m beyond the blast wall. The cameraman stayed at his post through all of this.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). Test of the early cut-off mechanism and engine control. The engine burned for 62 seconds, and total flight time was 287 seconds. The missile impacted 3 km left of the intended trajectory. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). The engine burned for 63.5 seconds, and total flight time was 291 seconds. The missile impacted 5 km right and 2 km short of the aimpoint. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). Test of the early cut-off mechanism and engine control. The engine burned for 60.5 seconds, and total flight time was 264 seconds. The missile impacted 3.4 km right of the intended trajectory. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 5.00 km (3.10 mi). Test of the early cut-off mechanism and engine control. Missile ascended vertically and exploded at T+70 seconds. The engine burned for 62.5 seconds, and total flight time was 200 seconds. The missile impacted 5 km right of the intended trajectory. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). Cut-off mechanism disabled and missile allowed to burn to fuel depletion. The engine burned for 65.1 seconds, and total flight was 318 seconds. The missile impacted 12 km right and 47 km beyond the aimpoint. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). Test of the engine cut-off mechanism. The engine burned for 64.9 seconds, and total flight was 316 seconds. The missile impacted 4.7 km right and 5 km short of the aimpoint. References: 950.

• Himmler's second visit to Peenemuende Nation: Germany. The rocket team and SS entourage discussed politics until 4 am. The next morning, the first demonstration launch of a V-2 failed - the missile turned west at an altitude of 200 m, and crashed in the woods outside of Peenmuende-West, destroying three aircraft on the nearby runway. Fortunately no one was killed. The second launch in the afternoon was successful. But the bureaucratic efforts by the SS and other organisations to take over the rocket program from the Army continued.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 1.00 km (0.60 mi). The missile entered a roll, headed in reverse inland, exploding in the woods by the runway of the Peenemuende West Luftwaffe test ground, killing three airman.The engine burned for 15 seconds, and total flight was 26.5 seconds. The missile impacted 178 degrees from its intended course.References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). The impact was not observed. The engine burned for 63.6 seconds, and total flight was 276 seconds. The missile impacted 11.8 km right and 4 km short of the aimpoint. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Test of the engine cut-off mechanism. The missile cut-off immediately after ignition, exploding on the pad. References: 950.

• Peenemuende given highest priority Nation: Germany. Dornberger, Von Braun, and Steinhoff (at the controls) fly aboard a He-111 to the Fuehrer bunker in East Prussia. There they give Hitler a review of the V-2 program, the first since his visit to Kummersdorf in March 1939. The appointment was for 11:30, but then delayed to 17:00.

  When they were finally ushered into his presence, Dornberger was shocked at the terrible and changed appearance of the Fuehrer. The team begins their briefing, in the presence of Hitler, Keitel, Jodl, Butale, and Speer. The presentation began with a film of preparations and launch of an A4 on the 3 October 1942. Von Braun narrated the film, which had proven a real crowd-pleaser in the past. It showed the A4 in production at the vast assembly hall at Peenemuende, the vertical roll-out, the huge launch complex, and finally launch. Von Braun then presented a model and plans for the hardened production/launch bunker that was being built on the English Channel.

  Hitler loved the bunker model, and declared he wanted to build not one, but three such facilities. Dornberger argued that mobile launchers would be militarily less vulnerable and less costly, but Hitler was unconvinced. The 7 m thick bunker walls, he declared, would 'draw every allied bomber like flies to honey. Every bomb they drop there will be one that does not fall on Germany'. Hitler asks if the payload can be increased to 10 tonnes (in order to accommodate a nuclear warhead) or if a 2,000 per month production rate was possible (in order to make mass attacks on Britain with conventional explosive or chemical payloads). Dornberger replies that it would take four to five years to develop a missile with greater payload, and that production was limited by the German industrial capacity for alcohol (used as fuel in the missile).

  Dornberger noted that they did not dream of the possibility of short-term availability of nuclear energy in 1936, when the specifications for the missile were set. In any case, after the loss of the heavy water plant in Norway, it would take years to develop nuclear weapons. Hitler was visibly upset that the V-2 would not turn out to be a war-deciding weapon. But Dornberger pointed out it was a great psychological weapon - unstoppable, something against their which there was no defence.

  Hitler stated that 'I have only had to excuse myself to two men in my life - and one of them was von Brauchtisch, who always championed the importance of your work, and the other is you. If we had this weapon in 1939, Britain would have conceded, and there would have been no war.

  Hitler finally ordered that the V-1 and V-2 missile programs be given the highest priority in the defence ministry. Immediately needed staff and material began flowing into the program. Saur immediately ordered a production goal of 2,000 missiles per month, despite the fact that there was no prospect of producing enough alcohol fuel or training enough launch crews to actual fire the missiles at such a rate. However, there was no disagreement, since any industry leader who did not commit to meeting this production goal was threatened with immediate replacement. German alcohol production would mean the maximum number that could ever be fired was 900 per month.References: 693.

• V-2 given top priority. Nation: Germany. Adolf Hitler gave the German V-2 program highest military priority. References: 17.

• Test mission Nation: Germany. Agency: Wehrmacht. Test of the engine cut-off mechanism. The missile veered inland, and impacted in the pumping station within the pad area. References: 950.

• Test mission Nation: Germany. Agency: Wehrmacht. Test of the engine cut-off mechanism. The missile cut-off at ignition. References: 950.

• V-2 program in crisis Nation: Germany. With only four months to go before Degenkolb's mandated production of 900 missiles per month, the engineers declare the missile is not ready for production. A workable engine has been developed, but it is complex, suitable for prototypes only, and the engineers involved do not have the experience to turn it into something designed for mass production. Continuous changes on the engine also affect other parts of the rocket, resulting in drawing changes simultaneous with the effort to mass-produce detailed parts. Thiel and his team declare that in fact development of the A4 can never be finished before the war's end. They recommend that plans to put it into production should be stopped. Thiel, at the verge of a nervous breakdown, led this engineering 'revolt', although Rees was the spokesman. They declare they would stop work at Peenemuende and retire to the university. Von Braun argued against this position, demanding that production continue. Dornberger suffered a crisis of confidence in the rocket team as a result of this fight, but decided to continue trying to get the missile in production and fielded with the Germany Army.References: 693.

• Peenemünde attacked by RAF. Nation: Germany. The Royal Air Force attacked Germany's Peenemünde Rocket Research Center, causing heavy damage and delaying V-weapon program by months.

  With the V-2 development program already in crisis, the Allies launch a massive bombing raid against Peenemuende. On that evening test pilot Hanna Reitsch was visiting the launch site. At 23:30 the air raid siren sounded. 600 British bombers drop 1500 tonnes of ordnance on the launch centre. However many bombs fell in the ocean around the peninsula, or buried themselves harmlessly in sand dunes. The resident area was hardest hit, while the Luftwaffe station at Peenemuende West was not touched. 47 British bombers were shot down - they were told before the raid that this was the most important mission of the war, and that their commanders would accept a 50% loss rate. 735 people were killed in the raid on the ground, including 178 of the 4000 inhabitants of the residential area. A large number of the foreign slave workers in the Trassenheide concentration camp barracks were also killed.

  After the tremendous raid the rocket team wander around the devastated facility, half-clothed, the buildings bathed in a weird light and everything covered in fine sand, as if flour was dropped over everything. Thiel and Walther - the two leading rocket engineers in Germany - were killed in the raid, and virtually all major facilities were damaged. The saving grace was that the soft sand of Peenemuende attenuated the blast of many bombs. Nine bombs hit the main assembly hall, but while there was splinter damage to some of the machine tools, there was no decisive hit that would prevent production from continuing. It was estimated that operations could resume in 4 to 6 weeks.

  The raid was not unexpected. The high altitude contrails of the V-2 test launches were called 'frozen lightning' and could be seen from Sweden on clear days. The location and purpose of Peenemuende appeared in a crossword puzzle in a illustrated magazine published in central Germany in early 1943. British reconnaissance flights to locate the launch facilities had been recognised for what they were.

  This raid, together with the bombing of V-2 production lines at the Zeppelinwerke in Friedrichshafen and the Raxwerke in Wiener Neustadt convinced Saur to reduce the V-2 production rate goal to 900 per month.References: 17, 693.

• V-2 production facilities bombed Nation: Germany. Ten days after the raid on Peenemuende, the British bomb the V-2 production/launch bunker under construction at Watten. Seven further bunkers (four in Pas-de-Calais, three at Cherbourg) continued to be built. Soon thereafter, V-2 production plants at Wiener Neustadt and Friedrichshafen are also bombed. Clearly the Allies had detected and targeted the infrastructure of the V-2 production program. In response to the raids, the decision was made that Organisation Todt would build an underground V-2 factory at a chalk mine in Witzen. The bunker at Watten would be used only as a liquid oxygen production plant. Hitler had mandated a 7 m thick protective roof there, which cannot be penetrated by Allied bombs. It was decided that the roof would be jacked up, the sides filled with concrete, and construction work would continue underground despite the perpetual bombing.References: 693.

• Dornberger meets with Hitler Nation: Germany. Hitler decides to continue work on the bunkers. In Dornberger's opinion, this wastes resources that could have resulted in an earlier, full deployment of the V-2 using motorised, mobile batteries. References: 693.

• Submarine-launched V-2 Nation: Germany. Director Lafferenz of the German Worker's Front proposed towing of a 3 m diameter x 30 m long capsule containing a single V-2 by submarine. This was later refined to a single submarine towing three 500 tonne capsules, each with a V-2, its propellants, and launch equipment. At the launch point water tanks would be flooded in the capsule to bring it upright, with the top above the surface. The top would be opened, then launch troops would enter to prepare and fuel the rocket, followed by launch. But the pressing problem of solving the A4's reliability problems and getting it into production delayed any further work on the concept until the end of 1944.References: 693.

• Heidelager test mission Nation: Germany. Agency: Wehrmacht. Apogee: 1.00 km (0.60 mi). All A4 production test and training launches after November were made from Blizna to either an impact range in Poland or into the Baltic Sea.

  The first launch made from Blizna was conducted by operational V-2 Battery 444. The launch stand was placed on sand, which the exhaust melted, causing one leg of the stand to tip into the soft surface. The missile ascended at an angle and crashed 3 km from the launch point. After this the decision was made to launch only from concrete surfaces.

  Two shots of the series that followed went out of control, landing west and north of Golingen, luckily impacting in uninhabited forest. The tests did not use explosive warheads, but still the craters made by the missiles' impact were still 30 m in diameter and 10 m deep. Missiles impacting in the Baltic were provided with green dye so that the impact location could be determined. The SS was responsible for any damage to civilian areas. The Baltic impact area was triangular, extending from Weichsel to Sam.

  The launches from Blizna were spectacularly unsuccessful - only 10% to 20% of the rockets were reaching the target. There were three categories of failures: thrust was lost just 20 m over the launch stand, causing the missile to fall back and explode, wrecking the stand; the missiles were exploding in the air at 1000 to 2000 m altitude during the burning time of the motor; and they would reach the full 250 km range, only to explode a few thousand metres over the target.

  No solution to these problems was found for a long time. Meantime three operational batteries were obtaining launch experience, using civilian technicians and engineers in military service. These launch troops got along well with the Peenemuende engineers, and made many practical recommendations for improvement of the missile and launch equipment.

  This period was the worst in the whole development of the A4. Finally it was determined that the rockets were failing due to an explosive mixture of alcohol forming in the internal spaces of the rocket, due to poor sealing compound used in initial production rockets (as opposed to a better-quality material used in Peenemuende-built prototypes). Improved seals and quality control eliminated the problem, and the crisis passed.References: 693, 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). References: 741.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 95 km (59 mi). References: 741.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 20 km (12 mi). References: 86.

• Mach 10 wind tunnel construction begins. Nation: Germany. A4 development is completed, so Peenemuende engineers can turn to full-scale development of the A9/A10. Construction of a Mach 10 wind tunnel to test hypersonic aerodynamic configurations for the missile begins. References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 20 km (12 mi). References: 86.

• First V-2 deliveries from Mittelwerk Nation: Germany. 4 or 5 missiles are 'delivered' in order to meet the end-of-the-year date set by the German leadership. They are immediately returned to the tunnel for rework. References: 727.

• V-2 guidance development Nation: Germany. Early A4's were equipped with a radio-controlled cut-off system. These were replaced in service versions by self-contained integrating accelerometers. Professors Bucholz and Wagner at Darmstadt had developed the system, which was shown to have the same accuracy as the radio-controled system. This system had been tested as early as the fall of 1939, but no production quantities were available until mid-1944. Gyroscopic guidance systems from Kresselgeraete GmbH were tested, but found to have inferior accuracy to the acceleromter-based system. For better precision a double integrator system was needed, but this could not be developed before the war's end. Virtually all A4 systems were developed by the engineers at Peenemuende rather than by industry. Some said that it would have been better handled by industry, but in fact there was no such thing as rocket technology when Von Braun's team began their work - it all had to be created.References: 693.

• V-2 sounding rockets Nation: Germany. Apogee: 189 km (117 mi). The Peenemuende team developed scientific payloads for a sounding rocket version of the V-2, to measure cosmic rays, meteoroid flux, and so on. However due to the pressure to solve the missile's reliability problems, these were never flown from Germany. Only after the war could these plans be implemented in New Mexico. However during the war there were some vertical shots of the missile to test its stability and behaviour in a vacuum. On one such shot the missile reached 189 km altitude. On another occasion four launch troops were killed when the missile ascended, then veered 90 degrees, turned again, and impacted in the launch pit at the point of launch.References: 693.

• Production V-2's exploding in flight. Nation: Germany. The production series of V-2's are exploding in flight, and the engineers cannot determine the reason. Peenemuende engineers sought to recover 30% of the missiles for detailed examination. This showed that re-entry heating did not weaken the missile's structure. There was no scorching of the 0.6 mm thick paint applied to the interior of the missile. Only the outer paint showed signs of scorching. The missile still suffered in-flight explosions - attributed to the re-entry heating of 480 deg C and residual propellant vapours that still escaped despite the better sealing. Dornberger thought the liquid oxygen tank was the problem, while Von Braun suspected the alcohol tank. To try to determine the cause, five V-2's were shot with the engine running until all of the alcohol was depleted. These were followed by six shots with improved glass wool insulation of the liquid oxygen tank, over the objections of Riedel III, head of manufacturing at Peenemuende. Three of these shots were made in one morning, and all went off course. These were in turn followed by a series of highly instrumented launches from Peenemuende. The improvements developed as a result of these tests improved the missile reliability from 30% to 70% immediately, and then the reliability slowly increased to 80% as additional changes were made. Only in the last months of the war was it found that the forward part of the outer hull was failing in flight. Once this was strengthened with a belt of sheet metal, the V-2 achieved essentially 100% reliability.

  This entire process was going on while production was ramping up at the underground facility at Mittelwerk. There was pressure from the highest quarters to get the missile fielded and attacks on England underway. Every change resulting from these tests and research meant that the production line at Mittelwerk had to be stopped, and retrofits made to undelivered missiles.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Mittelwerk Eval Test mission Nation: Germany. Agency: Wehrmacht. The first lot of missiles delivered from Mittelwerk had many manufacturing defects and were for the most part had to be reworked. S/N 17003 was the only one judged suitable for flight. References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• V-2 problems begin to be understood - but Peenemuende Rocket Team leaders arrested by SS Nation: Germany. The cause of early detonation of the warhead during the engine burn time is understood, but the crashes at the end of the trajectory are still a mystery. Dornberger is ordered to report to Hitler at Berchtesgaden. The call is received at 7 pm in the evening, following a bomb raid and ice storm. Dornberger is told that on the following morning Von Braun, Riedel II, and Groettrup are to be arrested for sabotage of the A4 program. Groettrup selects Dr Steinhoff as his representative. The men are accused of not putting all their energy in development of the A4 as a weapon - instead only using the financing of the Reich to support their private plans for manned spaceflight. Dornberger know he cannot complete the program without these men - Von Braun and Riedel were the key leaders, and Groettrup was head of the electrical systems section. Dornberger finally achieves their release by demonstrating to the SS that the biggest impediment to the program was Hitler's dream that the A4 would never reach London. After a few days in detention, Von Braun was moved to Schwedt, and then freed. The others were allowed out a bit later.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Around 30 V-2 missiles were launched in test and training missions from Heidelager in April 1944. Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 1.00 km (0.60 mi). References: 86.

• Test mission Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Around 30 V-2 missiles were launched in test and training missions from Heidelager in May 1944. Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 86.

• Renewed effort by the SS to take over Peenemuende Nation: Germany. The plan this time was for the launch centre to be privatised, made part of Siemens, with the SS running day-to-day operations. Dornberger was unsuccessful in fighting this effort off, and in July-August 1944 a series of government decrees gave the SS full control.References: 693.

• Test mission Nation: Germany. Agency: Wehrmacht. References: 86.

• Around 30 V-2 missiles were launched in test and training missions from Heidelager in June 1944. Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). References: 693, 86.

• Vertical test mission Nation: Germany. Agency: Wehrmacht. Apogee: 189 km (117 mi). On one such vertical shot the missile reached 189 km altitude - date unknown. References: 17, 693, 727.

• Vertical test mission Nation: Germany. Agency: Wehrmacht. Apogee: 176 km (109 mi). During the war there were some vertical shots of the missile to test its stability and behaviour in a vacuum. The precise dates were not recorded, but these became the first manmade objects to reach what was later defined as outer space (over 100 km altitude).References: 727.

• V-2 crashes in Kalmar, Sweden and is passed to British Nation: Germany. Agency: Wehrmacht. Apogee: 50 km (31 mi). The loss had occurred when a V-2 was being used to test the Wasserfall command guidance system. The rocket was being hand-guided and went into a cloud. The operator tried to turn it around, but instead it went out of sight in horizontal flight. Unknown to the Peenemuende rocket team, it continued north until it ran out of fuel and crashed, relatively intact (for a V-2). The question came down days later to Dornberger whether an A4 or Fi-103 launched from Peenemuende was unaccounted for - parts of a missile had been reportedly found in Sweden. Allied examination of this wreckage led to the incorrect belief that the V-2 was radio-controlled. Dornberger was asked by the leadership whether the V-2 design could be copied by the Allies based on the wreckage recovered. The answer was yes. But could they put it into production in a short time? Dornberger assured the leasdership the Allies could not. Hitler was furious and was going to have heads roll over the matter. Dornberger was called to Hitler's Quarters in Rastenburg, but was sent back without seeing the Fuehrer. Hitler had finally decided that the crash was actually a good lesson to Sweden, showing them what to expect if they joined the Allies. In addition, he was pleased with Dornberger's assessment that the Wasserfall radio guidance system would send the Allies down the wrong track in their understanding of the weapon. In fact, the remains of the V-2 were flown to England for Allied analysis, and the predicted incorrect conclusion regarding V-2 guidance was reached.References: 17, 769.

• Last V-2 launch from Heidelager. Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). Last launch from Heidelager. Russian advances forced the Germans to move the firing area to Heidekraut. A total of perhaps 24 missiles had been fired in test and training launches from Heidelager in July before it was abandoned. References: 693, 741.

• V-2 training launches begin from Heidekraut. Nation: Germany. Agency: Wehrmacht. Apogee: 90 km (55 mi). The Germans were forced by Russian advances to move the firing area to from Heidelager to Heidekraut, a location 15 km from Tuchel. Shots were made to the north and south from this location. A total of over 47 missiles were launched from Heidekraut in August, the last month of training before the combat campaign began.References: 86.

• Obergruppenfuehrer Kammler of the SS put in charge of the V-2 program. Nation: Germany. Dornberger was relegated to command of the training batteries for the rocket troops. Von Braun spoke to Dornberger, telling him that he must accept the situation and assist Kammler. Following the July 1944 assassination and coup attempt against Hitler, Dornberger had no backing in the leadership for keeping the program in Army hands. Dornberger finally agreed to cooperate - rockets had been his life's work, and he could not bear not to be involved. Dornberger hoped to 'put my words in Kammler's mouth and make them appear to be his'. All Army commanders in the rocket program were dismissed and replaced by SS officers - Kammler was in complete control.References: 693.

• Ma100 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 90 km (55 mi). References: 818.

• Ma106 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 818.

• Ma126 Training mission Nation: Germany. Agency: V-2 Bty 2./485. References: 818.

• Ma127 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 90 km (55 mi). References: 818.

• Ma123 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 818.

• Ma120 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 818.

• Ma108 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 818.

• Ma119 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 1.00 km (0.60 mi). References: 818.

• Ma115 Training mission Nation: Germany. Agency: V-2 Bty 3./836. References: 818.

• Ma125 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 40 km (24 mi). References: 818.

• Ma118 Training mission Nation: Germany. Agency: V-2 Bty 3./836. Apogee: 90 km (55 mi). References: 818.

• Ma114 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 819.

• Ma113 Training mission Nation: Germany. Agency: V-2 Bty 3./836. Apogee: 90 km (55 mi). References: 819.

• Ma128 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 90 km (55 mi). References: 819.

• Ma143 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 90 km (55 mi). References: 819.

• Ma140 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 819.

• Ma131 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 90 km (55 mi). References: 819.

• Ma132 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 819.

• Ma133 Training mission Nation: Germany. Agency: V-2 Bty 3./836. Apogee: 90 km (55 mi). References: 819.

• Ma138 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 819.

• Ma136 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 90 km (55 mi). References: 819.

• Ma111 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 90 km (55 mi). References: 818.

• Ma129 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 819.

• Ma109 Training mission Nation: Germany. Agency: V-2 Bty 2./836. Apogee: 90 km (55 mi). References: 818.

• Ma116 Training mission Nation: Germany. Agency: V-2 Bty 444. Apogee: 10 km (6 mi). References: 818.

• Ma142 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 819.

• Ma147 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 819.

• Ma107 Training mission Nation: Germany. Agency: V-2 Bty 2./485. Apogee: 90 km (55 mi). References: 819.