This brief bibliography is intended as a general guide for those who might wish to dig deeper into one of the many interesting topics the author has barely touched and for those interested in contemporary space history in general.
Bibliographies and Chronologies
Among the benefits of the space age are computers with enormous memory capacities. Some have stored a vast amount of references pertaining to aeronautics and space, including fuels such as hydrogen. The considerable interest in hydrogen today, from studies of energy alternatives, means that one must be quite restrictive in a bibliographical search to avoid being buried in computer read-out paper. Much of the computer-stored information on hydrogen is of fairly recent origin, however, and may not be applicable to an earlier period of interest. The author made use of selective bibliographical searches by NASA's RECON system, the Department of Defense's Documentation Center (Cameron Station, Alexandria, VA) and the Chemical Propulsion Information Agency (Applied Physics Laboratory, Johns Hopkins Univ., Silver Spring, MD). These are invaluable for locating specific reports on governmentsponsored research not generally in the published literature.
The chronology of greatest general use to the author was Eugene M. Emme, Aeronautics and Astronautics: An American Chronology of Science and Technology in tile Exploration of Space, 1915-1960 (NASA, 1961). This chronology provided many clues for digging deeper and also helped to relate other events with those pertaining to the subject. Several unpublished chronologies were found during the course of the research and are given in the notes; their scope was more restricted but equally valuable.
U.S. Propulsion Developments, 1945-1959
Histories. R. Cargill Hall, "Early U.S. Satellite Proposals," Technology and Culture, 4 (Fall 1963):410-34, and unpublished material on the same subject by Hall, in the NASA History Office, give an excellent account of satellites and rockets in 1945-1950. One of the contractors involved was the Aerojet Corporation; that company's rocket engine work is described by George H. Osborn, Robert Gordon, and Herman L. Coplen, "Liquid Hydrogen Rocket Engine Development, 1944-1950," presented at the 21st International Astronautical Congress, West Germany, 9 Oct. 1970. The "1944" in the title appears to be incorrect; actual research on hydrogen at Aerojet appears to have started late in 1945.
Cargill Hall's paper and others on the early development of rockets, plus papers on missile developments in the 1950s are in The History of Rocket Technology, Eugene M. Emme, ed. (Detroit: Wayne State University Press, 1964). Willy Ley's Rockets, Missiles and Space Travel (New York: Viking Press, 1961) is another source for rocket developments through the 1950s. John D. Clark's Ignition! An Informal History of Liquid Rocket Propellants (New Brunswick, NJ: Rutgers University Press, 1972) is a refreshing and candid view on propellants and research on them by a participant. Although he considers all propellants, most of Clark's attention was on storable or non-cryogenic propellants.
 Other highly useful histories are Robert L. Rosholt, An Administrative History of NASA, 1958-1963 (NASA SP-4101, 1966); Alfred Rosenthal, Venture into Space: Early Years of Goddard Space Flight Center (NASA SP-4301, 1968); Constance McLaughlin Green and Milton Lomask, Vanguard, A History (NASA SP-4202, 1970); and Thomas A. Sturm, The USAF Scientific Advisory Board: Its First Twenty Years, 1944-1964 (Washington, 1967).
Three PhD dissertations ate also very useful: Arthur Levine, "United States Aeronautical Research Policy, 1915-1958; A Study of the Major Policy Decisions of the National Advisory Committee for Aeronautics," Columbia Uviv., 1963; James Arthur Dewar, "Project Rover: A Study of the Nuclear Rocket Development Program, 1953-1963," Kansas State Univ., 1974; and Thomas Wilson Ray, "Apollo's Antecedents: The Conceptualization, Planning, Resource Build-Up, and Decisions That Led to the Manned Lunar Landing Program." Univ. of Colorado, 1974.
Books by Participants. Accounts by key participants in aeronautical and missile developments are invaluable for obtaining a good understanding of the subject. Among those found most helpful were Dwight D. Eisenhower, The White House Years: Waging Peace, 1956-1961 (Garden City, NY: Doubleday & Co., 1965); H. H. Arnold, Global Mission (New York: Harper & Bros., 1949); Herbert York, Race to Oblivion: A Participant's View of the Arms Race (New York: Simon & Schuster, 1970); J. B. Medaris with Arthur Gordon, Countdown for Decision (New York: G. P. Putnam's Sons, 1960); and Theodore von Kirmdn with Lee Edson, The Wind and Beyond (Boston: Little Brown & Co., 1967).
Technical Books. Technology and Uses of Liquid Hydrogen, ed. R. B. Scott, W. H. Denton, and C. M. Nicholls (New York: Macmillan & Co., 1964), goes right to the subject of this history of hydrogen and is one of the most useful technical sources. Within it is a chapter by Richard Mulready on Pratt & Whitney Aircraft's development of liquid hydrogen engines. Other very useful sources on liquid hydrogen during the 1950s are the first six volumes of Advances in Cryogenic Engineering, ed. K. D. Timmerhaus (New York: Plenum Press, 1960-1961); these contain papers presented at six conferences held during the 1950s.
The following text on propulsion systems was useful: George P. Sutton, Rocket Propulsion Elements (New York: John Wiley & Sons, 1949 and 1956), the classic for the period of interest. There are numerous texts on thermodynamics, turbomachinery, and aircraft engines. Those found helpful were: John F. Sandfort, Heat Engines (Garden City, NY: Doubleday, 1962), available in paperback; P. J. McMahon, Aircraft Propulsion (n.p.: Harper & Row, 1971); Mark W. Zemansky, Heat and Thermodynamics, 5th ed. (New York: McGraw-Hill, 1968); George F. Babits, Applied Thermodynamics (Boston: Allyn & Bacon, 1968); and D. G. Shepherd, Principles of Turbomachiner (New York: Macmillan & Co., 1956). A good reference on nuclear rockets is R. W. Bussard and R. D. DeLauer, Nuclear Rocket Propulsion (New York: McGraw-Hill, 1958).
Research and development reports. The reports of government laboratories and contractors were major sources for this history. These are found in a variety of ways: by prior knowledge of the activity, a bibliography of the organization doing the work or sponsoring it, references in other reports, literature searches, suggestions from colleagues or participants, and sometimes sheer luck. If there is an easy or systematic way, the author has yet to discover it. Sometimes an investigation may have been highly classified and no reports can be found. In other cases periodic progress reports were required regardless of results obtained, and there is a plethora of reports with a modicum of useful information in each. In investigating the hydrogen work at Ohio State University between 1945 and 1951, 91 references were found, ranging from bimonthly progress reports to one that summarized all the rocket work for the entire period. Seventy-one reports were identified for the hydrogen work of Aerojet Corporation between 1945 and 1949; these were briefly summarized by the Osborn, Gordon, and Coplen paper mentioned above. Clearly the best way to locate research and development reports sponsored by the government is with the help of government libraries. The author found the library services of the NASA indispensable. The task is sometimes more difficult than necessary, for many of the old reports still bear their original classification  markings and the services of a security official are necessary. Fortunately, the NASA officials I dealt with were knowledgeable and cooperative.
Other documents. Official correspondence, minutes of meetings, internal memoranda, patents, and other documents of government agencies and aerospace corporations are invaluable sources. Unfortunately, the pressure to clear files often results in the destruction of such material, but much is placed in retired files. The government maintains a retired records facility at Suitland, MD: it and the retired files of the Garrett Corporation proved very useful. Other helpful sources are those participants who keep their own records, especially the few rare ones with work diaries, but locating these depends on persistent inquiry and some luck.
Interviews. Interviews of participants in this history were major sources of information; the importance of oral history for recent events cannot be overemphasized. This was particularly true in the case of the Air Force's Supersecret Suntan program, where only a small amount of documentation has been located. In other cases, interviews furnished clues to other sources, helped to make sense of disconnected fragments, and gave color and background to otherwise dull events. Sometimes information from interviewees conflicts, but cross-checking and locating additional information or other clues help to clarify many of these conflicts. For those discrepancies that remain, perhaps a reader will come forward with better documentation or information. No one expects a participant's memory to be faultless or his view completely unbiased, but the author was impressed by the overall quality of the information from interviews, as well as the cooperativeness and objectiveness of those interviewed.
Pre-1945 Interest in Hydrogen
The best single source on hydrogen to the twentieth century is J. R. Partington, History of Chemistry, 4 vols. (London: Macmillan Co., 1961- ). Partington was a master at digging out details. The 2d, 3d, and 4th volumes are rich with references for those who wish more details. (Vol. 1 had not appeared in 1975.)
The works of several key contributors to the science and technology of hydrogen are especially helpful. One is the Scientific Papers of the Honourable Henry Cavendish, ed. T. Edward Thorpe (Cambridge: University Press, 1921). Another is the Collected Papers of Sir James Detvar, ed. Lady Dewar (Cambridge: University Press, 1927). Dewar's "History of Cold and the Absolute Zero," a paper he gave before the British Association for the Advancement of Science in 1902 and published in the Annual Report of the Smithsonian Institution for the same year, was very helpful. Two excellent accounts of cryogenics are: K. Mendelssohn, The Quest for Absolute Zero (New York: McGraw-Hill, 1966), and Michael McClintock, Cryogenics (New York: Reinhold, 1964).
Balloons and dirigibles, the first users of hydrogen in flight, have many excellent histories extending from Tiberius Cavallo, The History and Practice of Aerostation (London, 1785), which entranced the author, to Douglas H. Robinson, Giants in the Sky (Seattle: Univ. of Washington Press, 1973), an excellent treatise. The use of hydrogen in balloons and dirigibles is a subject in itself with much source material. The library of the National Air and Space Museum of the Smithsonian is a good place to start.
The most convenient English sources on both Tsiolkovskiy and Oberth are the translations of their works by the NASA (TT F-237, TT F-243, and TT F-622). NASA has also translated the multiple-volume works of N. A. Rynin; vol. 3, no. 7, is on Tsiolkovskiy.
The best single source on Goddard is the Papers of Robert H. Goddard, 3 vols., ed. Esther Goddard and G. Edward Pendray (New York: McGraw-Hill, 1970). An interesting and readable biography is Milton Lehman, This High Matt (New York: Farrar, Strauss, 1963). To go deeper, consult the National Air and Space Museum and the Goddard Memorial Library, the latter at Worcester, Mass.
Aeronautics, Engines, and Rockets through World War II
 The literature on early aeronautics is only of general interest for the subject of hydrogen. The Annual Reports of the National Advisory Committee for Aeronautics and other NACA publications are a rich source of aeronautical technical information: for a general Picture of early aeronautics, E. Charles Vivian and W. Lockwood Marsh. History of Aeronautics (New York: Harcourt. Brace & Co., 1921 ) is useful.
The best sources on aircraft engines-piston and jet-and aviation fuels through World War II are Robert Schlaifer. "Development of Aircraft Engines." and S. D. Heron, "Development of Aviation Fuels." published by Harvard Univ. in one volume in 1950 and reprinted by the Maxwell Reprint Co. in 1970.
Two excellent sources on the contributions of the Office of Scientific Research and Development during World War II are James Phinney Baxter III Scientsits against Time (Cambridge: MIT Press, 1946). and the Office of Scientific Research and Development series, Science in World War II (Boston: Little Brown & Co.. 1948), in which the volume Rockets, Guns, and Targets, ed. John E. Buchard, is of special interest.
German rocket developments before and during World War II have been well documented. The author used W. G. A. Perring. "A Critical Review of German Long-Range Rocket Development," Journal of the Royal Aeronautical Society 50 (July 1946): 483-525. for early postwar analysis of the V-2; Walter Dornberger, V-2 (New York: Viking Press. 1958), for the inside story of the German rocket build-up by a major participant: and James McGovern, Crossbow and Overcast (New York: William Morrow & Co., 1964), for an absorbing account of how the Allies obtained the services of German rocket experts.