The National Aeronautics and Space Administration (NASA) Science Mission Directorate (SMD) has determined that the Announcement of Opportunity (AO) Astrophysics Explorers Program 2025 Small Explorer release will be postponed until no earlier than April 2026. In the draft 2025 Astrophysics Small Explorer (SMEX) AO published earlier this year, Section 3. Proposal Opportunity Period and Schedule estimated the release of final SMEX text in April 2025.

In order to provide meaningful opportunities more effectively and efficiently for the proposer community, SMD’s Astrophysics Division (APD) will take additional time to refine the next SMEX AO. APD will ensure potential proposers are given adequate notice and preparation time to respond to any changes between the draft and any final AO text.

Comments and questions on the SMEX postponement will be accepted by email only. Anonymity of persons/institutions who question/comment will be preserved. No later than June 20, 2025, please address inquiries to Doris Daou, APD SMEX Program Scientist at Doris.Daou@nasa.gov and E. Lucien Cox APD SMEX Program Executive at Elbert.l.Cox@nasa.gov.

Similar questions/comments may be aggregated and provided with a single response. Responses may be given by email or posted in the Questions and Answers (Q&A) section on the SMEX Program Acquisition website.

• Draft AO Released: January 13, 2025
• Identification Number: NNH25ZDA008J
• Short URL: https://go.nasa.gov/NNH25ZDA008J

SMD remains committed to keeping the community informed as updates become available.