events
Explorer program: Explorer 9 (S-56a) is launched.
Related Wikipedia articles
Explorers Program
Ongoing NASA space exploration 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…Source: Wikipedia (CC BY-SA)
Explorer 9
NASA satellite of the Explorer program
Explorer 9, known as S-56A before launch, was a NASA satellite which was launched in February 1961 to study the density and composition of the upper thermosphere and lower exosphere. It was a reflight of the failed Explorer S-56 mission, and consisted of a 7 kg (15 lb), 3.66 m…Source: Wikipedia (CC BY-SA)