"Luna 2" carried five different types of instruments to conduct various tests while it was on its way to the Moon. The scintillation counters were used to measure any ionizing radiation and the Cherenkov radiation detectors to measure electromagnetic radiation caused by charged particles. The primary scientific purpose of the Geiger Counter carried on "Luna 2" was to determine the electron spectrum of the Van Allen radiation belt. It consisted of three STS-5 gas-discharge counters mounted on the outside of an airtight container. The last instrument on "Luna 2" was a three component fluxgate magnetometer. It was similar to that used on "Luna 1" but its dynamic range was reduced by a factor of 4 to ±750 gammas so that the quantisation uncertainty was ±12 gammas. The probe's instrumentation was powered by silver-zinc and mercury-oxide batteries.