False colour photograph of the sun and the moon, c1970s.

False colour photograph of the sun and the moon, c1970s. Taken from the Skylab space station. Skylab was launched on 14 May 1973 and was America's first manned orbiting space station. Visiting crews of three astronauts, could perform dozens of tests on each other to find out how well the human body copes with space travel. Three crews visited Skylab during its working life. The last mission was in February 1974, but Skylab remained in orbit until 1979. (Photo by Oxford Science Archive/Print Collector/Getty Images)