Space research days in the space station, but this achievement was quickly overshadowed since the crew died on reentry to Earth. Salyut 1 was intentionally deorbited six months into orbit since it prematurely ran out of fuel. Skylab was the first American space station. It was 4 times larger than Salut 1. Skylab was launched in May 19, 1973. It rotated through three crews of three during its operational time. Skylab’s experiments confirmed coronal holes and were able to photograph eight solar flares. From 1986 to 2001, Russian space station Mir served as a permanent microgravity research laboratory in which crews conducted
Orbit of the Moon frequencies. See also tidal acceleration for a more detailed description. The Moon is gradually receding from Earth into a higher orbit, and calculations suggest that this would continue for about 50 billion years. By that time, Earth and the Moon would be in a mutual spin–orbit resonance or tidal locking, in which the Moon will orbit Earth in about 47 days (currently 27 days), and both the Moon and Earth would rotate around their axes in the same time, always facing each other with the same side. This has already happened to the Moon—the same side always faces Earth—and is