LIGO Cosmic Explorer

LIGO Cosmic Explorer
Name	Cosmic Explorer
Caption	Conceptual illustration of a third-generation ground-based gravitational-wave observatory
Established	Project proposal in 2019
Location	United States (planned)
Affiliation	LIGO Laboratory, National Science Foundation

LIGO Cosmic Explorer

LIGO Cosmic Explorer is a proposed third-generation ground-based gravitational-wave observatory designed to succeed the Advanced LIGO detectors and to work in concert with international facilities such as Virgo (detector), KAGRA, and proposed facilities like Einstein Telescope. It aims to extend the reach of gravitational-wave astronomy to redshifts where early-universe compact-object populations and cosmological parameters can be probed, enabling multi-messenger campaigns with observatories including James Webb Space Telescope, Vera C. Rubin Observatory, and Athena (spacecraft). The project is organized within the LIGO Laboratory framework and is a major component of the United States strategy for 21st-century astrophysics coordinated with the National Science Foundation and national laboratories.

Overview

Cosmic Explorer is conceived as a long-baseline interferometer with arms significantly longer than those of LIGO Livingston Observatory and LIGO Hanford Observatory, building on technologies demonstrated by Laser Interferometer Gravitational-Wave Observatory projects and scientific results such as the detection of GW150914 and the binary neutron star event GW170817. The concept integrates lessons from milestone experiments and collaborations including Caltech, Massachusetts Institute of Technology, Stanford University, and national facilities like Lawrence Livermore National Laboratory and Fermi National Accelerator Laboratory. It is intended to operate synergistically with global partners such as European Gravitational Observatory and agencies including National Aeronautics and Space Administration for multi-messenger follow-up.

Design and Technology

The baseline design envisions interferometer arms on the order of 40–80 kilometers, leveraging advanced technologies developed at institutions like MIT Kavli Institute and OzGrav research groups. Key components include high-power lasers inspired by work at Max Planck Institute for Gravitational Physics (Albert Einstein Institute), cryogenic optics techniques explored by KAGRA engineers, and quantum-noise reduction methods tested at Caltech and LIGO Laboratory. Mirror substrate and coating research links to programs at National Institute of Standards and Technology and Brookhaven National Laboratory, while seismic isolation systems draw on developments from SLAC National Accelerator Laboratory and Jet Propulsion Laboratory. Control systems, data acquisition, and analysis pipelines will build upon software ecosystems maintained by LIGO Scientific Collaboration, Einstein@Home, and computational resources at XSEDE.

Science Goals and Expected Sensitivity

Scientific objectives include mapping black hole and neutron star populations across cosmic time, testing strong-field predictions of Albert Einstein's General relativity, constraining the equation of state of dense matter informed by nuclear experiments at Oak Ridge National Laboratory and CERN, and measuring cosmological parameters complementary to results from Planck (spacecraft) and Dark Energy Survey. Projected sensitivities aim to detect binary black hole mergers to redshifts z > 10 and binary neutron star events to z ~ 2–3, enabling joint observations with electromagnetic facilities such as Hubble Space Telescope and neutrino telescopes like IceCube Neutrino Observatory. Precision tests target potential beyond‑General‑Relativity signatures explored by theorists at Princeton University and Perimeter Institute, while stochastic background searches connect to early-universe scenarios studied at Institute for Advanced Study and Brookhaven National Laboratory.

Site Selection and Infrastructure

Candidate sites are evaluated across geological regions with input from agencies such as United States Geological Survey and local universities including University of California, Berkeley and University of Washington. Site criteria include low seismic noise, land availability for 40–80 km arms, and proximity to electrical and fiber-optic infrastructure maintained by utilities and institutions like Pacific Gas and Electric Company and Verizon Communications. Civil engineering work will engage firms and labs experienced with large scientific facilities, collaborating with Bechtel-level contractors and laboratory partners such as Argonne National Laboratory for environmental impact assessments and permitting with state authorities and tribal governments.

Project Status and Timeline

Following conceptual studies and white papers presented to the National Science Foundation and community panels such as the Particle Physics Project Prioritization Panel, the project advanced through design phases with input from the LIGO Scientific Collaboration and the broader gravitational-wave community. Milestones include technology demonstrators, site selection studies, and a phased construction schedule aimed for first science in the late 2030s to 2040s, contingent on funding decisions by agencies including the NSF and congressional appropriations committees. Demonstrator projects and prototype subsystems are being tested at university labs and national facilities such as MIT testbeds and Hanford Site test infrastructure.

Collaboration and Governance

Governance is expected to mirror models used by large-scale physics collaborations including the LIGO Scientific Collaboration, ATLAS (detector), and CMS (detector), with governance bodies drawn from academic institutions like Caltech, MIT, Columbia University, national laboratories such as Lawrence Berkeley National Laboratory, and international partners including European Gravitational Observatory and Australian Research Council-supported groups. Collaboration agreements will cover data access, publication policies, and detector operations, coordinated with funding agencies including the National Science Foundation and international counterparts like European Research Council.

Cost, Funding, and Policy Considerations

Estimated lifecycle costs encompass civil construction, vacuum systems, optics, lasers, and operations, with budgetary planning involving the National Science Foundation, congressional oversight committees, and stakeholder institutions such as California Institute of Technology and Massachusetts Institute of Technology. Funding models consider international cost-sharing with partners like European Union member research programs and contributions from national laboratories. Policy considerations include environmental review under state and federal statutes, workforce development coordinated with universities and workforce programs, and alignment with national priorities set by advisory bodies like the National Academies of Sciences, Engineering, and Medicine.

Category:Gravitational-wave observatories