As the decade of the 1960s neared its end, space science had become a firmly established activity. While the past had been immensely productive, world bent to the tasks that lay ahead. For their dissertations graduate students worked with their professors on challenging space science problems. With the loss of that air of novelty and the spectacular that had originally diverted attention from the purposefulness of the researchers, the field had achieved a routineness that equated to respectability among scientists.
Maturity underlay the field's hard-earned respectability.
Starting about 1964, in addition to the individual research articles published in the scientific journals, more comprehensive professional treatments of the kind that characterizes an established, active field of research began to appear. It is interesting, for example, to compare the book Science in Space published in 1960 with the second edition of Introduction to Space Science issued in 1968.