Explorer 26
Explorer 26 was a NASA satellite launched on 21 December 1964, as part of NASA's Explorer program. Its primary mission was to study the Earth's magnetic field. Spacecraft Explorer 26 was a spin-stabilized, solar-cell-powered spacecraft instrumented to measure trapped particles and the geomagnetic field and weighing . Experiments It carried five experiments: Solid-State Electron Detector, Omnidirectional and Unidirectional Electron and Proton Fluxes, Fluxgate Magnetometers, Proton-Electron Scintillation Detector, and Solar Cell Damage. The Solar Cell Damage experiment was intended to quantify the degradation of solar cell performance due to radiation, and evaluate the effectiveness of glass shields at preventing this degradation. A 16-channel PFM/PM time-division multiplexed telemeter was used. The time required to sample the 16 channels (one frame period) was 0.29 seconds. Half of the channels were used to convey eight-level digital information. The other channels were used for analog information. During ground processing, the analog information was digitized with an accuracy of 1/800th of full scale. One analog channel was subcommutated in a 16-frame-long pattern and used to telemeter spacecraft temperatures, power system voltages, currents, etc. A digital solar aspect sensor measured the spin period and phase, digitized to 0.036 seconds, and the angle between the spin axis and