Launching the Cosmic Explorer Conceptual Design

A new field of astronomy emerged in 2015 with the first detection of gravitational waves from colliding black holes by the U.S. National Science Foundation’s Laser Interferometer Gravitational-Wave Observatory (LIGO), resulting in the 2017 Nobel Prize in Physics for the project's founders. To date, LIGO and its international partners, Virgo and KAGRA, have discovered nearly 400 events, providing entirely new astrophysical knowledge, including the masses and spins of black hole populations and the origins of heavy metals in neutron-star collisions. Cosmic Explorer is the United States’ next-generation gravitational-wave observatory, one with arm-lengths ten times that of LIGO’s: a 40km, L-shaped interferometer with a reach into space that will extend across cosmic time. Cosmic Explorer will deliver transformative new capabilities in astrophysics, nuclear physics, and fundamental gravity. The observatory will probe the interior of neutron stars, test general relativity in extreme conditions, and detect black-hole and neutron-star mergers across the history of the universe. Together with partner facilities worldwide and ground-and space-based telescopes, Cosmic Explorer will enable a global, multi-band network that will revolutionize astronomy. This project will advance Cosmic Explorer designs and plans, including how science targets flow down and impact the design of the detector, foster the coordinated planning and development of the facility, detector, and computing systems, and provide specialized workforce development, a workforce that will lead the field of gravitational waves and impact STEM industries throughout the United States. Gravitational-wave astronomy has transformed our understanding of compact objects and spacetime. The U.S. scientific community has recognized that realizing the field’s full potential requires new, larger, more sensitive facilities. Cosmic Explorer (CE) is the U.S. concept for such a next-generation observatory. With a tenfold improved strain sensitivity over existing observatories, CE will detect hundreds of thousands to millions of sources per year, mapping compact-object populations across cosmic history, probing dense nuclear matter through neutron star mergers, and testing gravity in its strongest regimes. In 2022, NSF support launched the CE Conceptual Design effort, enabling significant technical design activity and the establishment of a Project Office and systems engineering team. This award will advance CE toward the maturity required for NSF’s Conceptual Design Review by taking steps to refine the science traceability matrix, integrate facility, detector, and computing designs, sustain and develop the CE Project Office, and continue development of a centralized infrastructure for coordination and workforce development. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.