In 1965, Eugene M. Emme, historian for the National Aeronautics and Space Administration (NASA), wrote a brief survey of the agency entitled Historical Sketch of NASA (EP-29). It served its purpose as a succinct overview useful for Federal personnel, new NASA employees, and inquiries from the general public. Because people were so curious about the nascent space program, the text emphasized astronautics. By 1976, a revision was in order, undertaken by Frank W. Anderson, Jr., publications manager of the NASA History Office. With a different title, Orders of Magnitude: A History of NACA and NASA, 1915-1980 (SP-4403), the new version gave more attention to NASA's predecessor, the National Advisory Committee for Aeronautics (NACA), although astronautics was still accorded the lion's share of the text. After a second printing, Anderson prepared a revised version, published in 1980, which carried the NASA story up to the threshold of Space Shuttle launches. Anderson retired from NASA in 1980.

As NASA approached the 75th anniversary of its NACA origins in 1915, a further updating of Orders of Magnitude seemed in order. In addition to its original audience, the book had been useful as a quick reference and as ancillary reading in various history courses; Anderson's graceful, lucid style appealed to many readers, including myself. The opportunity to prepare a revised survey was an honor for me.

Anderson's original discussions of astronautics have remained essentially intact; these are represented in the concluding section ("Enter Astronautics") in chapter 3 and by chapters 4, 5, 6, and 7 in this latest version. In recognition of the NACA's acknowledged contributions to aeronautical progress, I wrote the first three chapters, carrying the story up to the origins of NASA in 1958. Although chapters 4 through 7 are basically unchanged, I have included a more detailed summary of aeronautics in each of them to underscore the continuing evolution of aeronautical research during the era of Apollo. I also wrote chapters 8 and 9, bringing developments in aeronautics and astronautics up to the present. In addition, many of the photos have been replaced, a short bibliographical essay was added, and the index has been revamped. As in the past, Orders of Magnitude was not intended as a definitive or interpretive study of the NACA and NASA. Even so, two recurrent themes can be discerned. One is the continuing relationship between NACA/NASA and the military services; another is the ongoing interaction with the European aerospace community.

I am grateful to many people who have cooperated in preparing the manuscript: Sylvia Fries, the NASA historian and Lee D. Saegesser, NASA archivist; and W. David Compton, a valued colleague, read and commented on the entire manuscript. Lee Saegesser also saved me from various errors of fact and turned up essential illustrations. At the History Office at NASA's Johnson Space Center (JSC), I wish to thank Asha Vashi, Joey Pellarin, and Janet Kovacevich for supplying answers to many questions and for indefatigable good humor. Don Hess, who oversees the JSC History Office, facilitated access to JSC and its historical archives. At every NASA center, photo archivists and personnel in the Public Affairs offices provided necessary illustrations and information. Helen Heyder conscientiously typed different drafts of the entire manuscript. My family--Linda, Alex, and Paula--once again cheerfully endured the clutter of notes and books throughout our house.

In the process of defining the coverage and topics in this survey, I have been able to establish my own agenda, so that any shortcomings and errors are mine alone.

Roger E. Bilstein
Houston, Texas