Explorer 10
Explorer 10 (also known as Explorer X or P14) was a NASA satellite that investigated Earth's magnetic field and nearby plasma. Launched on 25 March 1961, it was an early mission in the Explorer program and was the first satellite to measure the "shock wave" generated by a solar flare. Mission The objective was to investigate the magnetic field and plasma as the spacecraft passed through Earth's magnetosphere and into cislunar space. The satellite was launched into a highly-elliptical orbit and was spin-stabilized with a spin period of 0.548 seconds. The direction of its spin vector was 71° right ascension and −15° declination. Spacecraft Explorer 10 was a cylindrical, battery-powered spacecraft instrumented with two fluxgate magnetometers and one rubidium vapor magnetometer extending from the main spacecraft body, and a Faraday cup plasma probe. The magnetometers were produced by Goddard Space Flight Center, and the Massachusetts Institute of Technology (MIT) provided the plasma probe. Experiments Faraday Cup Plasma Probe This experiment consisted of a Faraday cup with four grids and a collector designed to provide data on the density of the solar plasma and the magnitude and direction of its bulk motion. Protons were measured in the following energy ranges: 0