The Windows on the Universe: The Era of Multi-Messenger Astrophysics (WoU-MMA) program, supported by the National Science Foundation (NSF), promotes research that integrates observations from electromagnetic waves, high-energy particles such as neutrinos and cosmic rays, and gravitational waves. This multi-messenger approach enables unprecedented investigations into the universe, offering unique insights into matter, energy, and cosmic events. The program focuses on advancing capabilities and fostering collaboration to enable coordinated, interoperable, and interpretative research across these distinct observational windows.

The program identifies three critical areas of focus: coordination, which supports activities that integrate observations involving more than one messenger; observations, which fund studies of astrophysical phenomena that may produce signals detectable through multiple messengers; and interpretation, which includes theoretical, experimental, and computational work to analyze and understand multi-messenger observations. Proposals must address at least one of these criteria to be considered under WoU-MMA, with priority given to research that significantly advances multi-messenger astrophysics, facilitates community collaboration, and enhances workforce development in the field.

The WoU-MMA program does not replace existing NSF opportunities but complements them by focusing on projects with strong multi-messenger components. Proposals must explicitly request consideration under the WoU-MMA initiative by including "WoU-MMA:" at the beginning of the project title. Submissions that fail to align with at least one program criterion will be reviewed only under the participating program’s standard guidelines. Requests for supplements to existing NSF-funded projects that address WoU-MMA criteria will also be considered.

Eligible proposals must adhere to the guidelines outlined in the NSF Proposal & Award Policies & Procedures Guide (PAPPG) and be submitted through Research.gov or Grants.gov to one of the participating programs. Proposers are encouraged to contact program directors in the relevant divisions for guidance. Participating NSF divisions include the Division of Astronomical Sciences (AST) and Division of Physics (PHY) within the Directorate for Mathematical and Physical Sciences (MPS), and the Office of Polar Programs (OPP) within the Directorate for Geosciences (GEO). Where proposals span multiple programs, submissions should align with the primary program most relevant to the research objectives, while secondary programs may also be identified.

The program supports various opportunities under associated funding mechanisms, including research grants, postdoctoral fellowships, and specific focus areas such as gravitational physics, nuclear physics, plasma physics, and polar-based research. Deadlines and proposal windows vary depending on the related programs and submission guidelines. Investigators should consult the relevant program deadlines for compliance to ensure proposals are not returned as non-compliant.

Competitive proposals will accelerate progress in multi-messenger astrophysics through collaborative efforts, interoperability among research communities, and innovative theoretical and observational approaches. Examples include coordinated astronomical surveys, experiments combining high-energy particle and gravitational wave detection, and interpretation of multi-messenger data sets using advanced modeling and simulations. Workforce development and public outreach activities that broaden participation in astrophysics research are also encouraged.

Researchers must submit full proposals by 5 PM local time on the due date specified for the corresponding program. Proposers should contact the designated program officers for assistance: Hans Krimm (MPS/AST), Nigel Sharp (MPS/AST), Martin Still (MPS/AST), Vladimir Papitashvili (GEO/OPP), Darren Grant, Vyacheslav Lukin (MPS/PHY), and Pedro Marronetti (MPS/PHY). The WoU-MMA program strengthens NSF’s mission to advance fundamental knowledge and address emerging opportunities in astrophysics through multi-messenger discovery.