Latest Orbits Stories

In August 1960, NASA launched its first communications satellite, Echo 1. Fifty years later, NASA has achieved another first by placing the ARTEMIS-P1 spacecraft into a unique orbit behind the moon, but not actually orbiting the moon itself. This type of orbit, called an Earth-Moon libration orbit, relies on a precise balancing of the Sun, Earth, and Moon gravity so that a spacecraft can orbit about a virtual location rather than about a planet or moon. The diagrams below show the full...

Near the end of the mission of Apollo 16, on April 24, 1972, just before returning back home to Earth, the three astronauts released one last scientific experiment: a small "subsatellite" called PFS-2 to orbit the Moon about every 2 hours.The intention? Joining an earlier subsatellite PFS-1, released by Apollo 15 astronauts eight months earlier, PFS-2 was to measure charged particles and magnetic fields all around the Moon as the Moon orbited Earth. The low orbits of both...