>30 keV). The experiment operated satisfactorily from launch until 28 February 1961, except for a brief period in September and October 1960. Launch Launch was originally scheduled for late September 1959, but the mission was delayed for a week after a Jupiter IRBM test on an adjacent pad failed shortly after liftoff, causing flying debris to hit Explorer 7's launch vehicle. However, the damage to the booster was minor and could be easily repaired. Explorer 7 was launched on a Juno II at 15:31 GMT on 13 October 1959 from the Atlantic Missile Range into a orbit. On 16 June 1960, NASA announced one of the four frequency modulated subcarriers on the second transmitter had become erratic and the information it was transmitting on 3 of the 7 experiments was no longer intelligible. The tracking beacon ceased transmitting on 5 December 1959. As of September 1960 the orbit was with an inclination of 50.3° and a period of 101.2 minutes. Useful real-time data were transmitted from launch through February 1961 and intermittently until 24 August 1961. The spacecraft provided significant geophysical information on radiation and magnetic storms, demonstrated methods of controlling internal temperatures, recorded the first micrometeorite penetration of a sensor in flight, and detected large scale weather patterns. Mission results It transmitted data continuously through to February 1961 and went dead on 24 August 1961. It is still in orbit. See also S-1 (satellite) Explorer program References Spacecraft launched in 1959 Explorers Program Satellites orbiting Earth 1959 in the United States Earth observation satellites