Vanguard 2 (or Vanguard 2E before launch) is an Earth-orbiting satellite launched 17 February 1959 at 15:55:02 GMT, aboard a Vanguard SLV-4 rocket as part of the United States Navy's Project Vanguard. The satellite was designed to measure cloud cover distribution over the daylight portion of its orbit, for a period of 19 days, and to provide information on the density of the atmosphere for the lifetime of its orbit (about 300 years). As the first weather satellite and one of the first orbital space missions, the launch of Vanguard 2 was an important milestone in the Space Race between the United States and the Soviet Union. Vanguard 2 remains in orbit.