V-2 rocket

The V-2 rocket (German: Vergeltungswaffe 2, lit. 'Vengeance Weapon 2'), with the development name Aggregat-4 (A4), was the world's first practical, modern ballistic missile and suborbital launch vehicle. The missile, powered by a liquid-propellant rocket engine, was developed during the Second World War in Nazi Germany as a "vengeance weapon" and assigned to attack Allied cities as retaliation for the Allied bombings of German cities. After an altitude of 100 km was selected to define the edge of space, the V-2 rocket also became retroactively the first artificial object to travel into space with the vertical launch of MW 18014 on 20 June 1944.

Research of military use of long-range rockets began when the graduate studies of Wernher von Braun were noticed by the German Army. A series of prototypes culminated in the A4, which went to war as the V-2. Beginning in September 1944, more than 3,000 V-2s were launched by the Wehrmacht against Allied targets, first London and later Antwerp and Liège. According to a 2011 BBC documentary, the attacks from V-2s resulted in the deaths of an estimated 9,000 civilians and military personnel, while a further 12,000 laborers and concentration camp prisoners died as a result of their forced participation in the production of the weapons.

The rockets traveled at supersonic speeds, impacted without audible warning, and proved unstoppable. No countermeasures existed except for misdirection and attacks on launch sites and manufacturing facilities. However, postwar and historical assessments found they had little material or strategic impact on the war, despite the great cost of the program.