The National Science Foundation (NSF) DISCoVER Expedition will explore novel superconductor electronics as a viable post-CMOS computing technology. Superconductor electronics can deliver ultrahigh performance and energy efficiency at scale. DISCoVER will pave the way for seminal innovations in integrated electronics, sustainable exascale computing, and machine learning acceleration. DISCoVER will enable computing paradigms that can facilitate the modeling of climate change effects, detection of underground geological resources, enhancement of pharmaceutical drug design for personalized medicines and healthcare, and development of innovative smart materials and infrastructure. DISCoVER is supported by an NSF CISE Expedition in Computing award.