The author of the second and third volumes of the NASA Historical Data Book series relied on hundreds of individual sources to compile the many tables presented in them. Because so many sources were often consulted, no attempt was made to footnote each fact and figure; instead a major reference is usually cited for the researcher who needs more information than what is presented here. This note will serve as a further guide for the user who wishes to pursue the material from which these volumes were compiled.
NASA Headquarters' History Office in Washington, D.C., served as the author's office and primary source of documentary material. The following kinds of documents were available in the many program, project, and biographical files: NASA press releases, speeches, congressional testimony, contractor reports, related articles from periodicals - and newspapers, correspondence, and photographs. Especially important were mission operation reports (often cited as MORs) and midterm and prelaunch reviews. The author used such reports as her authority when confronted with conflicting data or memories. The serious researcher interested in the manned spaceflight program should also, consult the Johnson Space Center History Office and the related archives housed at the Fondern Library, Rice University, Houston, Texas.
In addition to these archival records, the author found the series Astronautics and Aeronautics, Chronology on Science, Technology and Policy to be most valuable. A&A, as it is commonly called, is compiled by staff members of the NASA Headquarters History Office; a volume is available for each year, starting with 1963. Three other general volumes the researcher should consult are: Helen Wells, Susan H. Whitely, and Carrie E. Karegeannes, Origins of NASA Names, NASA SP-4402 (Washington, 1976); Frank W. Anderson, Jr., Orders of Magnitude,- A History of NACA and NASA, 1915-1980, NASA SP-4403 (Washington, 1981); and House of Representatives, Committee on Science and Technology, Subcommittee on Space Science and - Applications, United States Civilian Space Programs, 1958-1978, Report (Washington, 1981). For those interested in how NASA managed its programs during the Apollo program, refer to Arnold Levine, Managing NASA in the Apollo Era, NASA SP-4102 (Washington, 1982). A useful tool for tracking the management of programs is the collection of NASA Headquarters and NASA center telephone directories kept at the NASA History Office.
The budget tables for all six chapters were compiled from one primary source, the "NASA Chronological History Fiscal Year Budget Submissions," prepared for Congress annually by NASA's Budget Operations Division of the Office of Administration, NASA Headquarters. Each volume lists the amount requested for that fiscal year (e.g., FY 1972), an estimate of the amount that will be programmed for the preceding year (e.g., FY 1971), and the amount actually programmed the year  before that (e.g., FY 1970). In addition to the budget figures, the volumes contain a, brief summary of the project and a statement of the work required during the com ing year. Please refer to the budget section of chapter I for more information on the budget process and the tables prepared for this book.
The author found the following major works to be useful in preparing the six chapters of the third volume (refer to the source notes for journal articles, papers, press accounts, and the like):
Baker, David. The Rocket: The History and development of Rocket & Missile Technology. New York: Crown Publishers, 1978.
Benson, Charles D. and William B. Faherty. Moonport; A History of Apollo Launch Facilities and Operations. NASA SP-4204, Washington, 1978.
Bilstein, Roger E. Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles. NASA SP-4206, Washington, 1980.
Belew, Leland F. and Ernst Stuhlinger, Skylab: A Guidebook. Marshall Space Flight Center, 1973.
Brooks, Courtney G., James M. Grimwood, and Loyd S. Swenson. Chariots for Apollo: A History of Manned Lunar Spacecraft. NASA SP-4205, Washington, 1976.
Compton, W. David and Charles D. Benson. Living and Working in Space: A History of Skylab. NASA SP-4208, Washington, 1983.
Ezell, Edward C. and Linda Neuman Ezell. The Partnership: A History of the Apollo-Soyuz Test Project. NASA SP-4209, Washington, 1978.
Ezell, Edward C. and Linda Neuman Ezell, On Mars: Exploration of the Red Planet. NASA SP-4212, Washington, 1983.
Newell, Homer E. Beyond the Atmosphere: Early Years of Space Science. NASA SP-4211, Washington, 1980.
Pitts, John. The Human Factor. NASA SP-4213, Washington, 1986.
Mack, Pamela E. "The Politics of Technological Change: A History of Landsat," unpublished doctoral dissertation, University of Pennsylvania, 1983.
 Chapter 5:
Hallion, Richard P. On the Frontier: Flight Research at Dryden, 1946-1981. NASA SP-4303, Washington, 1984.
Corliss, William R. "Histories of the Space Tracking and Data Acquisition Network (STADAN), the Manned Space Flight Network (MSFN), and the NASA Communications Network (NASCOM)." NASA CR-140390, June 1974.
In 1973, NASA adopted the metric system for its publications. Although many metric weights and measurements are now commonly used in the U.S., some may still seem foreign to the reader. Probably the most frequently questioned measurement is "newtons of thrust": pounds of thrust x 4.448. A useful publication for the user not familiar with the metric system is E. A. Mechtly, The International System of Units, Physical Constants and Conversion Factors, NASA SP-7012, 2d. rev. (Washington, 1973). Also be aware that the weights given for launch vehicles and spacecraft are "wet weights"; that is, the weight with fuel. Dates and times of mission events are local. Ground elapsed time is the amount of time in hours, minutes, and seconds that has elapsed since launch.