Special Notice NATIONAL AERONAUTICS AND SPACE ADMINISTRATION is seeking a partnership opportunity for a NASA MSFT - Astrophysics Small Explorer (SMEX) Spacecraft. This opportunity is in response to the expected NASA Astrophysics SMEX Announcement of Opportunity (AO), to be released in Quarter 3 (Q3) of FY2025. The partnership opportunity is being issued to select a teaming partner to provide a spacecraft bus. The spacecraft bus will be used for a mission concept proposed by NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, United States.