Appendix A

Statement of Task

As its second-priority recommendation in the category of large space-based activities, the 2010 astronomy and astrophysics decadal survey, New Worlds, New Horizons in Astronomy and Astrophysics (NWNH), recommended that to “[e]nable rapid response to science opportunities,” NASA “should support the selection of two new astrophysics MIDEX missions, two new astrophysics SMEX missions, and at least four astrophysics MoOs over the coming decade.” The 2016 midterm assessment report, New Worlds, New Horizons: A Midterm Assessment, clarified that the intent of this recommendation was that “this recommendation be for an augmentation of four missions during the time period 2012 to 2021, in addition to the two missions that would otherwise have been deployed, for a total of six.” The Midterm Assessment went on to recommend that “NASA’s Astrophysics Division should execute its current plan, as presented to the committee, of at least four Explorer Announcements of Opportunity during the 2012-2021 decade, each with a Mission of Opportunity call, and each followed by mission selection.” As the field approaches the next decade, and as NASA plans the next SMEX Announcement of Opportunity (AO), slated for 2018 or 2019, it is timely to assess the potential science reach of the SMEX mission class in order to best position the NASA Astrophysics Program for continued success and discoveries.

The CAA will write a brief report addressing whether there may or may not be sufficient compelling science motivations for a SMEX-sized mission to justify a SMEX Announcement of Opportunity (AO) in 2018 or 2019 (as is currently planned). In its report the CAA will also comment on the potential impact of any change to the planned 2018/19 SMEX AO on the NWNH-recommended program.