[1] Explorer 26 was a spin-stabilized, solar-cell-powered spacecraft instrumented to measure trapped particles and the geomagnetic field and weighing 45.8 kg (101 lb).

One analog channel was subcommutated in a 16-frame-long pattern and used to telemeter spacecraft temperatures, power system voltages, currents, etc.

[1] The purpose of this experiment was to measure the magnitude and direction of the Earth's magnetic field over the spacecraft orbit.

The experiment provided useful data from launch until 30 June 1965, after which spacecraft tumble rendered field direction determination impractical.

[4] Omnidirectional fluxes of 40- to 110-MeV protons and of electrons greater than about 4 MeV were separably measured by a plastic scintillator.

High-quality data transmission from this experiment was essentially continuous from launch until about the middle of 1966, and then intermittent.

[5] This experiment was designed to measure the directional fluxes and spectra of low-energy trapped and auroral protons and electrons.

The energy fluxes of electrons in three ranges were measured separately using scatter geometry, absorbers, and the phototube current.

[6] Trapped electrons and protons in the earth's Van Allen belts were measured using a combination of six omnidirectional and directional solid-state particle detectors (silicon p-n junctions).