Today in History

On January 31, 1958, the U.S. launched Explorer I (Alpha) from Cape Canaveral in Florida. This was America’s became first successful satellite.  The importance of the mission was political as well as scientific. The Soviets’ success with Sputnik 1 and Sputnik 2 the year before and America’s failed attempt  in December of 1957 made the mission important for American morale and to move the technology forward.

During the 1950s and the 1960s, there was a race to space that was part of the Cold War between the Soviet Union and the United States. Both nations were participating in the International Geophysical Year (IGY), which went from July 1957 to December 1958, and was an effort to provide cooperation and exchange of scientific information among a number of  nations across Europe, Asia, Africa, South America, and North America.

NASA Jet Propulsion Laboratory operated the spacecraft. The total weight of the satellite was 13.35 k (30.80 lbs.), which was lighter than the Soviet Sputnik 1. The information from the scientific instruments aboard the satellite was transmitted to the ground by two antennas. The instrumentation was built for simplicity and reliability and  is known for using an early form of transistor electronics. Among its scientific achievements, Explorer 1 had instruments that detected and provided evidence for intense bands of radiation that surround the Earth. These bands are called the Van Allen Radiation Belts, named after Professor James A. Van Allen, who directed the team of scientists that developed the instruments. Understanding of the Van Allen Radiation Belts proved critical for protecting astronauts during manned spaceflights as well as artificial satellites. This proved to be one of the biggest discoveries during the IGY.

After four months, Explorer I’s batteries ran out and it stopped providing data, but it remained in orbit until 1970. There were 90 Explorer space crafts in the series. The Smithsonian Institution’s National Air and Space Museum houses a replica of Explorer 1. Click here to read more about Explorer 1.