FINAL -- 2021 Astrophysics Medium Explorer (MIDEX) Announcement of Opportunity (AO)

The purpose of this SAM.gov amendment is to add a PDF file of an NSPIRES email entitled A1inSAM that extends the due date for the mandatory Notice of Intent (NOI) to propose to November 4, 2021. For details please download and carefully read the PDF file.

On or after the posting date of this SAM Combined Synopsis/Solicitation Notice, the FINAL text for 2021 Astrophysics Medium Explorer (MIDEX) Announcement of Opportunity (AO) may be downloaded from the NASA Solicitation and Proposal Integrated Review and Evaluation System (NSPIRES) https://nspires.nasaprs.com by searching on solicitation number NNH21ZDA018O or via the attached direct link.

Additionally, the Astrophysics Explorers Missions of Opportunity (APEXMO2) Program Element Appendix (PEA), Letter Q, in the Third Stand Alone Missions of Opportunity Notice (SALMON-3) will be available in final. In the event of any future lapses to the NASA operations, AO respondents should visit NSPIRES, the official NASA source for these AOs.

Open and carefully read the attached PDF file entitled 21AstroExplorersSynopsisandNSPIRESemail for other important dates and summary details.