The Planetary Science Division of NASA’s Science Mission Directorate released, on March 21, 2017, a Program Element Appendix (PEA) to the Third Stand-Alone Missions of Opportunity Notice (SALMON-3), soliciting proposals for the development of, and science investigations using, a Neutron and Gamma-Ray Spectrometer for the Japan Aerospace Exploration Agency (JAXA) Martian Moons eXploration (MMX) mission. The Pre-Proposal Conference for this PEA will be held, via Webex, on Monday, April 17, 2017, from 1:00 PM to 4:00 PM EDT. Details on attending this conference will be posted on the acquisition homepage for the MMX PEA: http://soma.larc.nasa.gov/mmx/ .