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The GPS satellite system
(Interesting Facts)

  • The 24 satellites that make up the GPS space segment are orbiting the earth about 19,312km above us.
  • They are constantly moving, making two complete orbits in less than 24 hours. These satellites are travelling at speeds of roughly 11,265 km/h.
  • GPS satellites are powered by solar energy. They have backup batteries onboard to keep them running in the event of a solar eclipse, when there's no solar power. Small rocket boosters on each satellite keep them flying in the correct path.
  • Also called NAVSTAR, the official U.S. Department of Defense name for GPS.
  • The first GPS satellite was launched in 1978.
  • A full constellation of 24 satellites was achieved in 1994.
  • Each satellite is built to last about 10 years. Replacements are constantly being built and launched into orbit.
  • A GPS satellite weighs approximately 907kg and is about 5.2m across with the solar panels extended.
  • Transmitter power is only 50 watts or less