Concept
Explorer 3
Related concepts (5)
Explorer 5
Explorer 5 was a United States satellite with a mass of . It was the last of the original series of Explorer satellites built, designed, and operated by the Jet Propulsion Laboratory. Explorer 5 was similar in all respects to Explorer 4 and was designed with the same basic science objectives, to make the first detailed measurements of charged particles (protons and electrons) trapped in the terrestrial radiation belts and to observe the effects of the Project Argus A-bomb detonations.
Explorers Program
The Explorers program is a NASA exploration program that provides flight opportunities for physics, geophysics, heliophysics, and astrophysics investigations from space. Launched in 1958, Explorer 1 was the first spacecraft of the United States to achieve orbit. Over 90 space missions have been launched since. Starting with Explorer 6, it has been operated by NASA, with regular collaboration with a variety of other institutions, including many international partners.
Explorer 1
Explorer 1 was the first satellite launched by the United States in 1958 and was part of the U.S. participation in the International Geophysical Year (IGY). The mission followed the first two satellites the previous year; the Soviet Union's Sputnik 1 and Sputnik 2, beginning the Cold War Space Race between the two nations. Explorer 1 was launched on 1 February 1958 at 03:47:56 GMT (or 31 January 1958 at 22:47:56 Eastern Time) atop the first Juno booster from LC-26A at the Cape Canaveral Missile Test Center of the Atlantic Missile Range (AMR), in Florida.
Sputnik 2
Sputnik 2 (ˈsputjnjɪk, Спутник-2, Satellite 2), or Prosteyshiy Sputnik 2 (PS-2, Простейший Спутник 2, Simplest Satellite 2) was the second spacecraft launched into Earth orbit, on 3 November 1957, and the first to carry an animal into orbit, a Soviet space dog named Laika. Laika died on the fourth orbit due to overheating caused by an air conditioning malfunction. Launched by the Soviet Union, Sputnik 2 was a cone-shaped capsule with a base diameter of that weighed around , though it was not designed to separate from the rocket core that brought it to orbit, bringing the total mass in orbit to .
Sputnik 1
Sputnik 1 ('spVtnIk,_'spʊtnIk, Спутник-1, Satellite 1) was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for three weeks before its three silver-zinc batteries ran out. Aerodynamic drag caused it to fall back into the atmosphere on 4 January 1958. It was a polished metal sphere in diameter with four external radio antennas to broadcast radio pulses.