SOMA 2016 Astrophysics Explorer Missions of Opportunity (MO)

The National Aeronautics and Space Administration (NASA) issues this Second Stand Alone Missions of Opportunity Notice (SALMON-2) Program Element Appendix (PEA) for the purpose of soliciting proposals for Astrophysics Mission of Opportunity (MO) science investigations to be implemented through its Explorers Program.
 
Since the early 1990s, the Explorers Program has provided several classes of flight opportunities for addressing astrophysics science objectives. These mission classes are defined by their cost caps and are designed to increase the number of flight opportunities in response to recommendations from the scientific community. The Explorers Program currently consists of larger stand-alone "full missions," and smaller investigations called "missions of opportunity."