During first Moon mission of the Space Launch System it is planned to take piggyback load - thirteen Cubesat satellites.
Space Launch System (SLS) is rocket developed since 2011, when President's Obama administration decided about cancelling Constellation project. Constellation was one of fundaments of George W. Bush administration plan called Vision for Space Exploration. It was based on Ares rockets and Orion spacecraft which were designed to replace Space Shuttle retired in 2011. In 2010 final decision about cancelling Ares program was made, but Orion spacecraft was still developed. In 2011 NASA after decision of Barack Obama's administration started developing new rocket able to be used for Moon and even Mars missions. First unmanned flight (EM-1 - Exploration Mission-1) of Orion Multi-Purpose Crew Vehicle and SLS rocket is planned on 2018. To maximize profits form mission NASA decided to prepare space on board of SLS for thirteen Cubesat satellites. But instead being launched and deployed in LEO like during other missions (for example like during ULA Atlas flights) this time Cubesats will reach deep space. According to NASA Deputy Administrator Dava Newman:
“The 13 CubeSats that will fly to deep space as secondary payloads aboard SLS on EM-1 showcase the intersection of science and technology, and advance our journey to Mars,”
Thanks to this decision NASA gather more data and perform more science experiments in deep space with very low cost. Cubesats will be deployed from mechanical deploying device installed on Orion spacecraft. After separation of Orion from upper stage, Cubesats will be deployed thanks to spring mechanism. Next they will start onboard transponders and start downlink.
For the moment we know NASA decision about ten places. Two places are booked for Next Space Technologies for Exploration Partnerships (NextSTEP) Broad Agency. Under this project Lockheed Martin will built remote sensing Cubesat called Skyfire which will flyby and gather data about Moon surface. Second Cubesat will be Lunar IceCube build by Morehead State University. It will try to gather data about water ice on the Moon during flight at altitude of 100 km over the Moon surface. Next three payloads are for NASA’s Human Exploration and Operations Mission Directorate; it decided to launch Near-Earth Asteroid Scout (NEA Scout which will perform reconnaissance during close flight near asteroid with utilization of solar sail). Next Cubesat will be BioSentinel for measuring influence of space radiation for biological material and Lunar Flashlight, Cubesat which will try to localize possible places where ice could be extracted from Moon surface. NASA’s Science Mission Directorate decided about two payloads - CuSP for magnetic fields monitoring and LunaH-Map for hydrogen level measuring. Next three places are booked for winners of Cube Quest Challenge organized by Space Technology Mission Directoriate of NASA. These places will be utilized by institutions which will propose most innovative solutions in spacecraft propulsion and communication technology which could be fitted in Cubesat satellite. Last three payloads will be utilized by international partners of NASA - there is no official statement about possible partnership with any particular national space organization.
On picture above you can see vision of Space Launch System ready to fire.