The NASA Science Mission Directorate (SMD) has released a third Community Announcement (CA) via www.SAM.gov that updates the special notice entitled DRAFT Announcement of Opportunity (AO) -- 2025 Astrophysics Small Explorer (SMEX) Notice ID NNH25ZDA008J stating NASA’s intention to solicit investigations for the Astrophysics Explorers Program in the second quarter of calendar year (CY) 2026.

SMD’s Astrophysics Division’s (APD) Explorers Program plans to release an Announcement of Opportunity (AO) entitled “2026 Astrophysics Small Explorer (SMEX)” during the 2^nd Quarter of CY 2026. In order to incorporate an initiative to improve proposal evaluation and mission development efficiency, the final APD SMEX 2026 AO text will differ from the previously released draft AO text located at https://go.nasa.gov/NNH25ZDA008J This CA provides advanced notice of the expected key differences between draft and final Astrophysics SMEX AOs relevant to pre- proposal activities initiated on the basis of the draft AO: 1) investigation proposals submitted to the APD SMEX 2026 AO will be selected on the basis of a single-step process. 2)In contrast with the draft APD SMEX 2025 AO, the selection process in the final APD SMEX 2026 AO will not include competitive Phase A studies. 3) The nominal projection for total duration of the combined Phase A&B concept development & preliminary design is 18 months. 

The forthcoming APD SMEX 2026 AO competition aims to select a single proposal to proceed as a NASA project in Phase A per NASA Procedural Requirements (NPR) 7120.5.

With this change to a single-step selection, some of the requirements marked Deferred Items in the Draft SMEX 2025 AO will not be deferred in the Final AO, in particular:

• Requirements 49 and 50 for naming the Project Manager and Project System Engineer.
• Requirements 43 and B-65 through B-69 (orbital debris and end of life) consistent with NPR 7120.5’s requirement for a preliminary ODAR at KDP-A.
• Requirement 38 to show compliance to the maximum channel bandwidth.
• Requirement 75 for a discussion of cost estimate error and uncertainty.
• The Final AO will also require draft project-level Level 1 and Level 2 Requirements, consistent with NPR 7120.5’s list of products for KDP-A.

The final AO text will be posted no earlier (NET) April 2026 on the NASA Solicitation and Proposal Integrated Review and Evaluation System (NSPIRES): https://nspires.nasaprs.com/external/.

AO participation will be open to all categories of U.S. organizations, including educational institutions, industry, not-for-profit organizations, Federally Funded Research and Development Centers, NASA Centers, and other Government agencies and non-U.S. organizations with some restrictions.

The time frame for the solicitation is intended to be:

Release of final AO………………….. 2^nd Quarter CY 2026 (NET April)

Pre-proposal conference……………. ~3 weeks after final AO release

Notice of Intent due………………….. NET 45 days after AO release

Proposals due………………………... NET 90 days after AO release

Selection announced………………… 1^st Quarter CY 2027 (target)

SMEX launch readiness date………. NLT 3rd Quarter CY 2031

Any costs incurred by prospective investigators in preparing submissions in response to a CA are incurred at the submitter's own risk. The forthcoming final AO may contain provisions that differ from this preliminary notice, in which case the provisions in the AO will take precedence.

Additional information will be posted, as it becomes available, by the NASA Langley Research Center (LaRC) Science Office for Mission Assessments (SOMA) on its 2026 Astrophysics SMEX Acquisition website at https://explorers.larc.nasa.gov/APSMEX26/SMEX/index.html.

Questions or comments about this intention to release an Astrophysics SMEX 2026 AO may be addressed via email to John Wisniewski, Astrophysics Small Explorers Program Lead Scientist, SMD, john.p.wisniewski@nasa.gov and E. Lucien Cox, Astrophysics Small Explorers Program Executive, SMD, elbert.l.cox@nasa.gov using subject line “APD 2026 SMEX CA”.

Email questions/comments no later than February 26, 2026, 11:59 p.m. Eastern time. Depending on the nature of the question(s), NASA may respond on an individual basis by email or may post responses to inquiries on the Questions and Answers (Q&A) pages on the SOMA 2026 Astrophysics SMEX Acquisition website. Anonymity of persons or institutions submitting questions will be preserved.