Nuclear data needs for the study of nucleosynthesis in massive stars

The critical nuclear physics needed to calculate the evolution of and nucleosynthesis in massive stars is reviewed with emphasis on the uncertainties. Some reaction rates - the most important and uncertain still being C-12 (alpha, gamma)O-16 - are important for energy generation and stellar structure. Others, like Ne-22(alpha,n)Mg-25 and individual cross sections for neutron capture determine the overall yield and distribution of the s-process for elements lighter than A = 90. Still others affect the synthesis of individual nuclei, e.g., by the nu-process, the rp-process, and the gamma-process. Weak interaction rates are important in determining the structure of both the pre-collapse and the post-collapse supernova core. Finally, both the site for, and the nuclear physics of the r-process remains very uncertain, quite possibly because of the neglect of magnetic fields.