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Adapted from: John A. Eddy,"Skylab optics: an introduction",Appl. Opt. 16,4, 823, (1977)

Skylab was launched on 14 May 1973. For nearly 9 months, until 8 February 1974, it was successfully operated with and without astronaut crews as the world's first space station of major size. It was an overwhelming success.

Skylab was bigger than a boxcar and weighed, on earth, almost 100 tons. A part of that mass was expendable food, water, oxygen, and life-support equipment for its three, three-man crews who lived and worked on board through successive missions of first 28, then 59, and finally 84 days. But a major portion was a massive payload of scientific and engineering equipment, largely of an optical nature. The goals of Skylab were to observe the lands and oceans and atmosphere of the earth, and the sun and stars above, and to carry out on-board medical and engineering experiments. It was designed as well to evaluate the ability of man to live and work efficiently in a weightless condition for long periods of time, in part to gauge the practicability of more advanced manned laboratories in the future.

Skylab was a scientist's spacecraft: its experiments were many and sound and foremost in the mission. They were the reason that Skylab was there. Scientific, medical, and engineering experiments occupied almost all the hours of the long days of each astronaut crew. And most of them were carried out with full-scale, laboratory- or observatory-sized equipment. For the first time in space there were few constraints on experiment weight, power, telemetry, or film storage. For the first time, solar astronomers were able to take advantage of photographic emulsions in long-term observational patrols from space. For the first time repairs and modifications were made on experiment equipment during the operational phase-within the Skylab and outside it, during spacewalks by astronaut crews. In this way the first crew salvaged the entire mission. From there on the three crews carried out adjustments, brought up replacement parts and installed them, tinkered, improvised, made changes, and generally worked as scientists do in a ground- based laboratory. Their effectiveness was beyond imagination.

More than anything else Skylab was a laboratory of optical instruments, in the broadest definition, spanning the full reach of the electromagnetic spectrum from hard x rays to radio waves. It was surely the largest assemblage of lenses and mirrors, reticles, prisms, windows, filters, gratings, cameras, films, photomultipliers, computers, and electrooptical systems ever lofted above the surface of the earth. One important area: the solar experiments that comprised the Apollo Telescope Mount (ATM) is described in the following section. Richard Tousey, the author, holds the Frederic Ives Medal of the Optical Society of America and is one of the world's pioneers in optical experimentation from space. He was Principal Investigator for three of the solar exper iments on Skylab and participated in the demanding, day-to-day operations of Skylab controlled from Houston. In his introduction he reminds us that Skylab was more than a 10-year effort.