Editing Explorer 2 (section)

== Spacecraft ==
Explorer 2 was identical to [[Explorer 1]] except for the addition of a tape recorder designed to enable playback of data. The satellite was a {{cvt|203|cm}} long, {{cvt|15.2|cm}} diameter cylinder and nosecone that comprised the fourth stage of the Jupiter-C launch vehicle. With a mass of {{cvt|14.22|kg}}, it was about {{cvt|0.25|kg}} heavier than Explorer 1. The spacecraft body was made of stainless AISI-410 steel, {{cvt|0.058|cm}} thick. The case was heat-oxidized to a gold color and eight alternate stripes of white Rokide A (flame sprayed aluminum oxide) were used for temperature control.<ref name="Display">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=EXPLR2|title=Display: Explorer 2 EXPLR2|publisher=NASA|date=14 May 2020 |access-date=13 February 2021}} {{PD-notice}}</ref>

The base of the cylinder held the Sergeant solid-fuel rocket motor. The sub-carrier oscillators and [[Mercury battery|Mallory mercury batteries]] for the low power transmitter were in the upper part of the nose cone. Below these was the low power (10 mW, 108.00 MHz) transmitter for the carrier and sub-carrier signals, which used the stainless steel satellite skin as a dipole antenna.<ref name="Display"/>

Below the nose cone was the detector deck, holding the Geiger-Mueller counter tube for the cosmic ray experiment, the command receiver, for recorder interrogations, high power playback transmitter (60 mW, 108.03 MHz) for interrogation response, cosmic ray experiment electronics, Mallory mercury batteries for the high power transmitter, and a {{cvt|0.23|kg}}, {{cvt|5.7|cm}} diameter magnetic tape recorder. An acoustic micrometeorite detector was mounted to the inside of the spacecraft cylinder near the cosmic ray device. Near the bottom of the detector deck four circularly polarized turnstile stainless steel wire whip antennas protruded radially from the side of the spacecraft, equally spaced around the axis. A gap for the high powered antenna and a heat radiation shield were between the payload and the rocket motor. The micrometeorite detectors were arranged in a ring around the cylinder near the bottom of the spacecraft. Four temperature gauges were mounted a various locations in the spacecraft.<ref name="Display"/>

Explorer 2 was equipped with a [[Geiger counter]] for the purposes of detecting [[cosmic ray]]s. After [[Explorer 3]], it was decided that the original Geiger counter had been overwhelmed by strong radiation coming from a belt of charged particles trapped in space by the [[Earth's magnetic field]] (see: [[Van Allen radiation belt]]). Explorer 2 was also equipped with a wire grid array and an acoustic detector for the purpose of [[micrometeoroid|micrometeorite]] detection.