A historic connection of Clayton's academic career to NASA's Apollo Program arose through establishment by Rice University of its Department of Space Science in 1963. This action by Rice University provided the academic position assumed by Clayton in 1963. Clayton described this good fortune in his autobiography. in graduate education throughout the world. At Rice Clayton was awarded the newly endowed Andrew Hays Buchanan Professorship of Astrophysics in 1968 and held that endowed professorship for twenty years until responding to the opportunity to guide a new astrophysics program at
Clemson University in 1989. During the 1970s at Rice University Clayton guided Ph.D. theses of many research students who achieved renown, especially
Stanford E. Woosley, William Michael Howard, H. C. Goldwire, Richard A. Ward, Michael J. Newman, Eliahu Dwek, Mark Leising and Kurt Liffman. Senior thesis students at Rice University included Bradley S. Meyer and
Lucy Ziurys, both of whom forged distinguished careers in the subjects of those senior theses. Historical photos of several students can be seen on Clayton' s photo archive for the history of nuclear astrophysics. Clayton followed the historic Apollo 11 mission while on holiday with his family in Ireland while traveling to Cambridge UK for his third research summer there. Letters in winter 1966 from W.A. Fowler unexpectedly invited Clayton to return to Caltech in order to coauthor a book on
nucleosynthesis with Fowler and Fred Hoyle. In his autobiography Clayton quotes these letters. He accepted that offer but the book was never written because while he was resident at Caltech Clayton was invited by Fred Hoyle to
Cambridge University (UK) in spring 1967 to advise a research program in nucleosynthesis at Hoyle's newly created
Institute of Astronomy. The award to Clayton of an
Alfred P. Sloan Foundation Fellowship (1966–68) facilitated leaves of absence from Rice University for this purpose. Clayton exerted that research leadership in Cambridge during 1967-72 by bringing his research students from Rice University with him. That prolific period ended abruptly by Hoyle's unexpected resignation from Cambridge University in 1972. Clayton was during these years a Visiting Fellow of
Clare Hall. At Rice University W.D. Arnett, S.E. Woosley, and W.M. Howard published jointly numerous innovative studies with Clayton on the topic of explosive
supernova nucleosynthesis. During his Cambridge years, Clayton proposed radioactive gamma-ray-emitting nuclei as nucleosynthesis sources for the field of
gamma-ray astronomy of line transitions from radioactive nuclei with coauthors (
Stirling Colgate,
Gerald J. Fishman, and
Joseph Silk). Detection of these gamma-ray lines two decades later provided the decisive proof that
iron had been synthesized explosively in supernovae in the form of radioactive
nickel isotopes rather than as iron itself, which Fowler and Hoyle had both advocated. During (1977–84) Clayton resided part-time annually at the
Max Planck Institute for Nuclear Physics in
Heidelberg as
Humboldt Prize awardee, sponsored by Till Kirsten. Annual academic leaves from Rice University facilitated this. There he joined the
Meteoritical Society seeking audience for his newly published theoretical picture of a new type of isotopic astronomy based on the relative abundances of the isotopes of the chemical elements within interstellar dust grains. He hoped that such interstellar grains could be discovered within
meteorites; by which the effects of stardust can be measured in meteoritic minerals even if stardust itself no longer exists there. Clayton designated the crystalline component of interstellar dust that had condensed thermally from hot and cooling stellar gases by a new scientific name,
stardust. Stardust became an important component of
cosmic dust. Clayton has described and with student Mark D. Leising computed a propagation model of positron annihilation lines within nova explosions and of the angular distribution of gamma ray lines from radioactive
26Al in the galaxy. Following laboratory discovery in 1987 of meteoritic
stardust bearing unequivocal isotopic markers of stars, Clayton was awarded the 1991
Leonard Medal, the highest honor of the Meteoritical Society. Feeling vindicated, Clayton exulted in
Nature "the human race holds solid samples of supernovae in its hands and studies them in terrestrial laboratories". In 1989 Clayton accepted a professorship at Clemson University to develop a graduate research program in astrophysics there. to vitalize joint research with the
Compton Gamma Ray Observatory (launched in 1991 after several delays). Its four instruments successfully detected gamma-ray lines identifying several of the radioactive nuclei that Clayton had predicted to be present in supernova remnants. Clayton had been designated ten years earlier co-investigator on the NASA proposal submitted by James Kurfess for the Oriented Scintillation Spectrometer Experiment
OSSE, one of the four successful instruments carried into orbit by
Space Shuttle Atlantis, and he carried that research contract to Clemson. Simultaneously Clayton developed at Clemson his stardust research, introducing annual workshops for its researchers. The initial NASA-sponsored workshop at Clemson in 1990 was so lively that it was repeated the following year jointly with Washington University in St. Louis cosponsorship, and in later years cosponsored also by the
University of Chicago and by the
Carnegie Institution of Washington. These workshops featured the excitement of new isotopic discoveries, and also helped participants focus their ideas for submission of abstracts to NASA's Lunar and Planetary Science Conference. Otherwise participants' workshop discussions were not shared or publicized. Eventually a unique new goal became to assemble from his large personal collection of photographs a web-based archive for the history of nuclear astrophysics and to donate the original photographs to the Center for the History of Physics, a wing of the
American Institute of Physics. The thrusts of Clayton's career at Clemson University are well represented on that Photo Archive by photos between 1990 and 2014. Following his retirement from academic duties in 2007, Clayton remained quite active in research problems involving condensation of dust within supernovae and has also published a scientific autobiography,
Catch a Falling Star. Clayton's published refereed research papers prior to 2011 are listed at http://claytonstarcatcher.com/files/documents/JournalPub.pdf ==Personal life==