Explorer 14 was a spin-stabilized, solar-cell-powered spacecraft instrumented to measure cosmic-ray particles, trapped particles, solar wind protons, and magnetospheric and interplanetary magnetic fields. It was the second of the S 3 series of spacecraft, which also included Explorers 12, 15, and 26. A 16-channel PFM/PM time-division multiplexed telemeter was used. The time required to sample the 16 channels (one frame period) was 0.323 s. Half of the channels were used to convey eight-level digital information, and the others were used for analog information. During ground processing of the telemetered data, the analog information was digitized with an accuracy of 1/100th of full scale. One analog channel was subcommutated in a 16-frame-long pattern and was used to telemeter spacecraft temperatures, power system voltages, currents, etc. A digital solar aspect sensor measured the spin period and phase, digitized to 0.041 s, and the angle between the spin axis and sun direction to about 3-deg intervals. The spacecraft functioned well except for the period from January 10 to 24, 1963, and after August 11, 1963, when the encoder malfunctioned terminating the transmission of usable data. Good data were recorded for approximately 85% of the active lifetime of the spacecraft. The spacecraft was coning (37-deg maximum half-angle) until January 10, 1963. After January 24, 1963, it was spin-stabilized at a rate of 10 rpm. This rate slowly decreased to 1 rpm on July 8, 1963. Initially, the local time of apogee was 0700 h.