V-2

The V-2 (German: Vergeltungswaffe 2, "retaliation weapon 2"), technical name Aggregat-4 (A4), was a short-range ballistic missile that was developed in Germany.

Commonly referred to as the V-2 rocket, the liquid-propellant rocket was the world's first long-range combat-ballistic missile and first known human artifact to enter outer space. It was the progenitor of all modern rockets, including those used by the United States and Soviet Union's space programs.

Technical details

At launch the V-2 propelled itself for up to 65 seconds on its own power, and a program motor controlled the pitch to the specified angle at engine shutdown, from which the rocket continued on a ballistic free-fall trajectory. The rocket reached a height of 80 km after shutting off the engine.

The V-2 was guided by four external rudders on the tail fins, and four internal graphite vanes at the exit of the motor. The LEV-3 guidance system consisted of two free gyroscopes (a horizontal and a vertical) for lateral stabilization, and a PIGA accelerometer to control engine cutoff at a specified velocity. The V-2 was launched from a pre-surveyed location, so the distance and azimuth to the target were known. Fin 1 of the missile was aligned to the target azimuth. Some later V-2s used "guide beams", radio signals transmitted from the ground, to keep the missile on course, but the first models used a simple analog computer that adjusted the azimuth for the rocket, and the flying distance was controlled by the timing of the engine cut-off, "Brennschluss", ground controlled by a Doppler system or by different types of on-board integrating accelerometers. The rocket stopped accelerating and soon reached the top of the approximately parabolic flight curve.

V-2 sounding rocket

Rockets captured by the United States Army at the end of World War II were used as sounding rockets to carry scientific instruments into the earth's upper atmosphere at White Sands Missile Range (WSMR) for a program of atmospheric and solar investigation through the late 1940s. Rocket trajectory was intended to carry the rocket about 160 km high and 48 km horizontally from WSMR Launch Complex 33. Impact velocity of returning rockets was reduced by inducing structural failure of the rocket airframe upon atmospheric re-entry.

Sounding rocket performance

V-2 sounding rockets were 14 m long and 1.65 m in diameter and weighed 13,000 kg with a full load of liquid fuel contributing two-thirds of that weight. The fuel was consumed in the first minute of flight producing a thrust of 250 kN. Maximum acceleration of 6 Gs was reached at minimum fuel weight just before burnout, and vibrational accelerations were of similar magnitude during powered flight. Velocity at burnout was approximately 1,500 m per second. The rocket would typically have a small, unpredictable angular momentum at burnout causing unpredictable roll with pitch or yaw as it coasted upward approximately 121 km. A typical flight provided an observation window of 5 minutes at altitudes above 56 km.