[vii] The success of the Skylab mission and its Apollo Telescope Mount (ATM) has been a thrilling event to those of us who have been engaged with NASA since 1958 in planning and consummating solar research missions in space. Conceived in 1965 as a relatively simple exercise to test man's capability for doing useful work in space, the ATM concept was subjected to a continuous process of critical review, revision, and upgrading by NASA, working in concert with industry and the scientific community. The ATM that finally emerged became one of the most important milestones in the history of solar astrophysics. The mission in fact represented the final step in the initial long-term strategy for solar astrophysics that was set by the Space Science Board of the National Academy of Sciences in 1960, which called for the installation in space of a very large orbiting solar observatory, weighing several thousand megagrams and comparing favorably with ground-based observatories as regards lightgathering power and angular and spectroscopic resolution.
In terms of versatility, sensitivity, and reliability, the performance of the ATM telescopes and instruments exceeded the highest aspirations of astronomers during the 1960's. Yet, the mission appeared headed for total and complete disaster, until rescued by the heroic and skillful exploits of the astronauts in repairing the damage incurred by the spacecraft during launch. In this and other ways, the role of man in the operation of space observatories was clearly, even brilliantly, delineated.
The study of ATM observations has already led to many new discoveries about the nature of the Sun and about the fascinating events that occur on even a very ordinary star. Especially illuminating has been the recognition of the extent to which the Sun's magnetic field is responsible for the structure, dynamics, and heating of the Sun's outer layers. So massive was the harvest of information, however, that it will be many years before the possibilities for productive analyses are exhausted. I am confident that well before that time we shall have gained such entirely new perspectives on the Sun that we will be confronting a brand new set of questions and addressing them with a second generation of solar space experiments.