failed to operate normally (only every fourth scan spot could be successfully reproduced), further reducing the resolution. The last useful data were obtained on 25 August 1959. VLF Receiver (15.5 kHz) This Very low frequency (VLF) receiver was designed to study Whistler mode propagation and ionospheric moise on 15.5 kHz signals transmitted from Annapolis, Maryland. The signals were received on a small electric antenna which was simultaneously used to transit Very high frequency (VHF) telemetry. The signal intensity on a 3-db bandwidth of 100 hz was observed along with the antenna impedance. The dynamic range of the receiver was about 80 db. This experiment operated from launch up to about 160 km before failure. With the antenna in a folded configuration for launch, the receiver recorded all data at a sensitivity reduced by about 30 db. At , the signals disappeared into the noise background. However, by special techniques, data were made usable all the way up to . Launch The satellite was launched into a highly elliptical orbit, on 7 August 1959, at 14:24:20 GMT. First image of Earth by a satellite On 14 August 1959, Explorer 6 took the first image of Earth ever by a satellite. It was over Mexico at an altitude of approximately . The image was a very crude picture of the north central Pacific Ocean, transmitted to a ground station in Hawaii over a 40 minute span. ASAT test On 13 October 1959, an anti-satellite missile (ASAT) test of the Bold Orion missile used Explorer 6 as a target. The missile successfully passed within of the satellite. Launch took place within the Atlantic Missile Range Drop Zone (AMR DZ). The altitude, latitude and longitude of the drop point were , 29° North and 79° West, respectively. Bold Orion successfully intercepted the Explorer 6 satellite, passing its target at a range of less than and an altitude of . Mission The satellite was spin-stabilized at 2.8 rotation per seconds (rps), with the direction of the spin axis having a right ascension of 217° and a declination of 23°. Four solar cell paddles mounted near its equator recharged the storage batteries while in orbit. Each experiment except the television scanner had two outputs, digital and analog. An Ultra high frequency (UHF) transmitter was used for the digital telemetry and the TV signal. Two Very high frequency (VHF) transmitters were used to transmit the analog signal.