NASA, an acronym for the National Aeronautics and Space Administration, is an independent agency under the United States federal government responsible for overseeing the nation's civilian space program and conducting research related to aeronautics. Established on July 29, 1958, in response to the Soviet Union's successful launch of the first artificial satellite, NASA took an active role in space exploration, launching numerous space missions, unmanned probes and landing astronauts on the moon during the Apollo missions. NASA also manages the International Space Station, the Hubble Space Telescope amongst many other astronomical observatories, and collaborates with international partners to advance the understanding of the universe, earth sciences, and aerospace technology.