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
Halo orbit each Lagrange point. Because halo orbits tend to be unstable, stationkeeping is required to keep a satellite on the orbit. Most satellites in halo orbit serve scientific purposes, for example as space telescopes. Robert W. Farquhar first used the name "halo" for these orbits in his 1968 Ph.D. thesis. Farquhar advocated using spacecraft in a halo orbit on the far side of the Moon (Earth–Moon ) as a communications relay station for an Apollo mission to the far side of the Moon. A spacecraft in such a halo orbit would be in continuous view of both the Earth and the