When Dr. Ernst Stuhlinger, Chief of Research at the Army Ballistics Missile Agency, pushed the firing button at 10.48 pm Eastern Standard Time on 31 January 1958, the age of astronautics also began for the Western world. With pushing this button, Explorer 1 was roaring sent into space by means of a Jupiter C rocket. The Jupiter C (a modified Redstone rocket) had been developed by the team around Dr. Wernher von Braun in less than three months. It was America's answer to the Sputnik. Jupiter C was a four-staged rocket. The first stage had been powered with liquid fuel whereas stages two and three had been powered by solid propellant. The fourth stage was fixed to the satellite. Explorer 1 was equipped with measuring instruments that helped to discover the Van-Allen radiation belt. This American satellite was the first with the name Explorer, but 54 others should follow. Only for two months Explorer 1 sent data to earth, but it made more than 58,000 orbits around the earth before it burnt up in the upper layers on 31 March 1970.