AO Astrophysics Explorers Program 2026 SMEX Amended - NASA Science
The National Aeronautics and Space Administration (NASA) Science Mission Directorate (SMD) announces the release of Amendment #1 to the Announcement of Opportunity (AO) to solicit Principal Investigator (PI)-led space science investigations for the Small Explorer (SMEX) opportunity.
Announcement of Opportunity Astrophysics Explorers Program 2026 Small Explorer (SMEX) Amended Text Released11 August 2026The National Aeronautics and Space Administration (NASA) Science Mission Directorate (SMD) announces the release of Amendment #1 to the Announcement of Opportunity (AO) to solicit Principal Investigator (PI)-led space science investigations for the Small Explorer (SMEX) opportunity under the Astrophysics Explorers Program on the NASA Solicitation and Proposal Integrated Review and Evaluation System (NSPIRES). To find the full amended AO text and a copy of Amendment #1 visithttps://nspires. nasaprs. com/, and select “Solicitations” at the top of the page, and on the next page in the search box, input the number “NNH26ZDA011O” or use the direct short URLhttps://go. nasa. gov/APSMEX26. In the event of any lapse in NASA operations, please visit NSPIRES for further information. Changes within the AO text are noted by using bold for new text and strikethrough for deleted text. The proposal due date,9 September 2026, remains unchanged. For a summary of the changes made to the AO, locate the Amendment #1 document on the right side of the AO landing page on NSPIRES. Additionally, the official Question and Answers (Q&A) document has been updated on the Science Office for Mission Assessments (SOMA) web site athttps://explorers. larc. nasa. gov/APSMEX26/SMEX. All new questions or comments about the Astrophysics SMEX 2026 AO shall be addressed via email to Dan Moses, APSMEX26 Lead Program Scientist,dan. moses@nasa. gov; Hannah Jang-Condell, APSMEX26 Deputy Program Scientist,hannah. jang-condell@nasa. gov; and Omar Torres, Lead Acquisition Manager for the 2026 Astrophysics SMEX AO, SOMAomar. torres@nasa. govusing subject line “APSMEX26” to be properly routed. The Q&A period for the SMEX 2026 AO ends 14 days before the proposal due date. Any costs incurred in preparing a submission in response to this notice or the full APSMEX26 AO are solely the responsibility of the submitter. NASA ScienceNSPIRESNASA Solicitation and Proposal Integrated Review and Evaluation SystemExplore