Cosmic Explorer: a next-generation ground-based gravitational wave observatory

Cosmic Explorer (CE) is a next-generation ground-based gravitational wave observatory envisioned to begin operations in the 2030s. With its spectacular sensitivity in the audio band CE will observe black hole and neutron star systems from the first stars, and nearer-by systems with signal to noise ratios in the thousands, while also opening a wide discovery space to the novel and unknown. The observational science possible with CE will be described, along with some of the key technologies and instrument science targeted to reach the observatory performance goals.