Editing Nuclear thermal rocket (section)

== Early history ==
In 1944, [[Stanisław Ulam]] and [[Frederic de Hoffmann]] contemplated the idea of controlling the power of nuclear explosions to launch space vehicles.<ref name=":0">{{cite book |last1=Corliss |first1=William R. |last2=Schwenk |first2=Francis C. |title=Nuclear Propulsion for Space, Understanding the Atom Series |date=1971 |publisher=[[United States Atomic Energy Commission]] |id={{ERIC|ED054967}} |osti=1132518 |pages=11–12 }} {{PD-notice}}</ref> After World War II, the U.S. military started the development of [[intercontinental ballistic missiles]] (ICBM) based on the German [[V-2 rocket]] designs. Some large rockets were designed to carry nuclear warheads with nuclear-powered propulsion engines.<ref name=":0"/> As early as 1946, secret reports were prepared for the [[United States Air Force|U.S. Air Force]], as part of the [[Aircraft Nuclear Propulsion|NEPA project]], by [[North American Aviation]] and [[Douglas Aircraft Company]]'s [[Project RAND|Project Rand]].<ref>{{cite report |doi=10.2172/7365651 |title=LASL nuclear rocket propulsion program |date=1956 |last1=Schreiber |first1=R.E. |url=https://digital.library.unt.edu/ark:/67531/metadc1449128/ }} {{PD-notice}}</ref> These groundbreaking reports identified a reactor engine in which a working fluid of low molecular weight is heated using a nuclear reactor as the most promising form of nuclear propulsion but identified many technical issues that needed to be resolved.<ref>{{cite book|last=Serber|first=R.|title=The Use of Atomic Power for Rockets |publisher=Douglas Aircraft Company|date=5 July 1946}}</ref><ref>H. P. Yockey, T. F. Dixon (1 July 1946), "A Preliminary study on the Use of Nuclear Power in Rocket Missiles", Report NA-46-574</ref><ref>R. Gomog (3 August 1946), "Rocket Computations", Report NEPA-508 {{PD-notice}}</ref><ref>L. A. Oblinger (13 August 1946), "Pilot Plant for Nuclear Powered Aircraft", Report NEEA-505</ref><ref>L. A. Ohlinger (21 November 1946) "Controls for Nuclear Powered Aircraft", Report NEPA-511 {{PD-notice}}</ref><ref>Feasibility of Nuclear Powered Rockets snd Ramjets, Report NA 47-15, February 1947</ref><ref>"Nuclear-Powered Flight", LEXP-1, 30 September 1948</ref><ref>{{cite report |last1=Redding |first1=E. M. |title=The Feasibility of Nuclear-Powered Rockets |date=8 September 1948 |publisher=Masschusetts Inst. of Tech., Cambridge. Lexington Project |osti=969679 }}</ref>

In January 1947, not aware of this classified research, engineers of the [[Applied Physics Laboratory]] published their research on nuclear power propulsion and their report was eventually classified.<ref>A. E. Ruark ed. (14 January 1947) "Nuclear Powered Flight", APL/JEU-TG-20</ref><ref name=":0"/><ref name=":1">{{cite book|last=Schreiber|first=R. E.|url=https://fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00339473.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00339473.pdf |archive-date=2022-10-09 |url-status=live|title=The LASL nuclear rocket propulsion program|publisher=LANL|year=1956|volume=LAMS 2036}} {{PD-notice}}</ref> In May 1947, American-educated Chinese scientist [[Qian Xuesen]] presented his research on "thermal jets" powered by a porous graphite-moderated nuclear reactor at the Nuclear Science and Engineering Seminars LIV organized by the [[Massachusetts Institute of Technology]].<ref>{{cite book|last=Tsien|first=H. S.|title=The Science and Engineering of Nuclear Power|publisher=Addison-Wesley Press|year=1949|editor-last=Goodman|editor-first=C.|volume=2|chapter=Rockets and Other Thermal Jets Using Nuclear Energy|quote=(Presented at a Massachusetts Institute of Technology seminar in 1947)}}</ref><ref name=":1"/>

In 1948 and 1949, physicist [[Leslie Shepherd (physicist)|Leslie Shepherd]] and [[rocket scientist]] [[Val Cleaver]] produced a series of groundbreaking scientific papers that considered how nuclear technology might be applied to [[interplanetary travel]]. The papers examined both nuclear-thermal and [[Nuclear electric rocket|nuclear-electric]] propulsion.<ref>{{cite journal|last1=Shepherd|first1=L. R.|last2=Cleaver|first2=A. V.|date=September 1948|title=The Atomic Rocket I|journal=Journal of the British Interplanetary Society|volume=7|issn=0007-084X|pages=185–194}}</ref><ref>{{cite journal|last1=Shepherd|first1=L. R.|last2=Cleaver|first2=A. V. |date=November 1948|title=The Atomic Rocket II|journal=Journal of the British Interplanetary Society|volume=7|issn=0007-084X|pages=234–241}}</ref><ref>{{cite journal|last1=Shepherd|first1=L. R. |last2=Cleaver |first2=A. V.|date=January 1949|title=The Atomic Rocket III|journal=Journal of the British Interplanetary Society|volume=8|issn=0007-084X|pages=23–27}}</ref><ref>{{cite journal|last1=Shepherd|first1=L. R. |last2=Cleaver|first2=A. V.|date=March 1949|title=The Atomic Rocket IV|journal=Journal of the British Interplanetary Society|volume=8|issn=0007-084X|pages=59–70}}</ref>