COBE's three instruments presented unique challenges. Each instrument had its own principal investigator (PI), so there were different executive styles. Also, the Science Working Group was constituted as co-investigator on all three instruments, so there were team-level challenges and significant conflicts to be managed, as documented in the book The Very First Light: The True Inside Story of the Scientific Journey Back to the Dawn of the Universe. John Mather is the senior project scientist for the James Webb Space Telescope at Goddard Space Flight Center. His research centers are on infrared astronomy and cosmology. As an NRC postdoctoral fellow at the Goddard Institute for Space Studies (New York City), he led the proposal efforts from 1974 to 1976 for the Cosmic Background Explorer (COBE) and came to Goddard to be the study scientist (1976–1988), project scientist (1988–1998), and principal investigator for the far-infrared absolute spectrophotometer on COBE.