Report Series: Committee on Astronomy and Astrophysics : Small Explorer Missions

The 2010 astronomy and astrophysics decadal survey, New Worlds, New Horizons in Astronomy and Astrophysics, laid out an exciting portfolio of recommended activities to guide the agencies'research programs over the period 2012-2021. The newly constituted Committee on Astronomy and Astrophysics (CAA) is tasked with monitoring the progress of the survey's recommended priorities. The CAA met in conjunction with Space Science Week 2017 in Washington, D.C., on March 28- 30, 2017. This was the first meeting at which the CAA could produce a report, and in advance of that meeting, the CAA received a question from NASA about an upcoming Small Explorer (SMEX) mission call. This report addresses 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).