Siting the Cosmic Explorer Observatory

This collaborative, multidisciplinary project focuses on the site identification and evaluation for Cosmic Explorer (CE), a proposed next-generation U.S. gravitational-wave observatory. The initiative aims to identify two distinct observatory sites within the continental United States: a primary facility featuring an L-shaped configuration with two $40\text{ km}$ arms (totaling $80\text{ km}$), and a second facility with $20\text{ km}$ arms.

Utilizing a mixed-methods Geographic Information Systems (GIS) approach, this project builds upon previously established evaluation criteria—including science, cost, workforce, and synergies—developed via a National Suitability Analysis (NSA) and the Cosmic Explorer Location Search (CELS) cost estimation code.

The core objective is to refine and narrow the existing "long list" of 10 promising $40\text{ km}$ locations and 10 promising $20\text{ km}$ locations down to a vetted "short list" of six viable sites for each facility. This interdisciplinary evaluation balances technical requirements for accurate scientific observations with human-centric factors, ensuring nearby communities offer a high quality of life and manageable commutes for observatory staff. Ultimately, this project will cultivate local partnerships and deliver a comprehensive report detailing the science, cost, and workforce opportunities for each shortlisted location, directly supporting a subsequent NSF-led site selection decision.