above +80°C. Telecommunications Data were continuously transmitted using a 60 mW amplitude-modulated transmitter and a 10 mW phase-modulated transmitter, both transmitting as a frequency of 108 MHz. Data were recorded only when the spacecraft was over one of seventeen receiving stations. Both the high-power and low-power transmitters were battery powered and operated. Launch vehicle The launch vehicle was a Juno I, a variant of the three-stage Jupiter-C with an added fourth propulsive stage, which in this case was the Explorer 2. The first stage was an upgraded Redstone liquid-fueled launch vehicle. The second stage comprised a cluster of eleven Sergeant solid-fuel rocket motors and the third stage held three Sergeants. The booster was equipped to spin the fourth stage in increments, leading to a final rate of 750 rpm about its long axis. Mission Explorer 2 launched from the Cape Canaveral Missile Test Center of the Atlantic Missile Range (AMR), pad 26A, on 5 March 1958 at 18:27:57 GMT. The flight was nominal through third stage ignition. The fourth stage failed to ignite, making attainment of orbital velocity impossible. The spacecraft reentered the atmosphere and fell into the Atlantic Ocean near Trinidad, some from the launch site. The cause of the failure was believed to be due to failure of a light plastic cone, which held the igniter in place at the fourth stage nozzle, under the launch stresses. This allowed the igniter to fall out of position. The igniter support was strengthened for later flights. See also Explorer 1 Explorer program References External links Spacecraft launched in 1958 Explorers Program Satellite launch failures