The V-2 is a familiar rocket. It’s the rocket the German Army developed during the Second World War that was launched against Allied cities including London, Paris, and Antwerp by the Nazis. But the rocket technology acquired from Hitler’s war machine spawned the basis for the more peaceful space launch capabilities we take for granted today.

The V-2 wasn’t a stand-alone design, however. It was part of a larger family of rockets, some early test beds and other more sinister variations that happily never came to fruition during the war.

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The V-2 — which stands for Vergeltungswaffe Zwei or Vengeance Weapon 2 — was so named by the Nazi propaganda ministry. To its designers it was known as the A-4, the fourth in the Aggregate series of rockets.

The Aggregate series was dreamed up by Wernher von Braun and the team of rocket engineers he worked with before and during the Second World War. Working at a small site called Kummersdorf West outside of Berlin in 1933, the team developed the first Aggregate rocket called the A-1. It was the first liquid-fueled rocket with some major changes from early test beds. Namely, this rocket had the engine mounted in the rear rather than forward in the nose. Still, it was a small test rocket one foot in diameter and 4.6 feet long.

Trial-and-error problem solving with the A-1 led to development of the A-2. This second Aggregate had the same basic structure as its predecessor, but with one major difference: the gyroscope in its body that ensured straight and level flight was moved from the rocket’s nose to the center of its body. This proved to be a much more successful design.

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After two A-2s named Max and Moritz were launched successfully, the German Army took the rocket group under its wing and funded development of the larger A-3, a rocket that didn’t formally exist.

The A-3 was a significant improvement over its predecessors, thanks to its sophisticated guidance system. It was also the first rocket designed to launch vertically from a standing position on its own fins, rather than launched from guide rails.

Building off the successful launches with the A-1, the A-2 and the A-3, von Braun’s team designed the A-4. The A-4 was meant to be the first operation rocket to meet the German Army’s design requirements. It was designed to deliver one metric ton of explosives to a target 155 miles away.

But the differences between the A-3 and A-4 were significant enough to demand an intermediary test rocket. This was the A-5, a 21.3-foot long rocket 2.6 feet in diameter that served as a test bed for engineers to figure out the details of the A-4’s flight characteristics. The A-5 first flew in the fall of 1939 with an additional two dozen launches in the years that followed.

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Once the A-4 program began in earnest, it was the rocket team’s focus throughout the war. But the program didn’t end with this most famous Aggregate rocket. The rocket team continued designing bigger and better rockets even as the war came to a close, namely the A-9 and the A-10 that both had a range of 1,900 miles and were developed for more peaceful applications.

The A-9 was one of the first, if not the very first, rocket-powered airplane designed to fly. It came to life in 1943 as a spinoff of the A-4 and was based on the idea that this rocket would eventually become a reliable, supersonic, long-range vehicle. Von Braun and his team reasoned that they could extend the flight time and range of an A-4 by adding wings. Rather than have it fly over the atmosphere and fall ballistically to a target, wings would make it glide through the atmosphere. They calculated that a powered flight covering just 12 miles could yield a top speed for the vehicle of 2,800 miles per hour. This could translate to a range of 350 miles covered in just 17 minutes.

But the A-9 wasn’t an autonomous rocket like the A-4. The A-9 was meant to be flown by a pilot. It was designed with a pressurized cockpit and a tricycle landing gear for runway landings.

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While the A-9 was taking shape, the rocket team starting planning how they could take it a step further with a booster rocket called the A-10. This was the first multi-stage spaceplane system. The A-10 would propel the A-9 for the first minute or so of its flight then fall away, it’s useful life over. The A-9 would then continue flying under its own power to a maximum speed of 6,300 miles per hour at an altitude of 35 miles. It’s propulsive power exhausted, it would glide supersonically to a target 2,500 miles away.

Like the A-9, the A-10 could was meant to be pilots. It could carry a man from Europe to New York in 40 minutes. Alternatively, it could be made automated and carry a warhead across the Atlantic at the same time. The A-10 might have been an early spaceplane to some. To others it had the potential to be an early intercontinental ballistic missile.

The A-9 made two research flights towards the end of the Second World War, proof of concept flights that showed the winged A-4 was a sound design. But the test program ended abruptly as Germany crumbled around the northern rocket research center at Peenemunde. Luckily the technology didn’t reach America in the form of bombs carried by A-10s. The knowledge that made the Aggregate rocket series a success eventually reached America in the minds of the scientists who immigrated in the 1940s and 1950s.

Sources: The Nazi Rocketeers by Dennis Piszkiewicz