Spaceflight as a practical endeavor began during World War II with the development of operational liquid-fueled rockets. Beginning life as a weapon, the V-2 was pressed into peaceful service after the war at the United States' White Sands Missile Range as well as the Soviet Union's Kapustin Yar. This led to a flourishing of missile designs setting the stage for the exploration of space. The small American WAC Corporal rocket was evolved into the Aerobee, a much more powerful sounding rocket. Exploration of space began in earnest in 1947 with the flight of the first Aerobee, 46 of which had flown by the end of 1950. These and other rockets, both Soviet and American, returned the first direct data on air density, temperature, charged particles and magnetic fields in the Earth's upper atmosphere.
