Cubesats are small, low cost space probes that can be used to collect scientific data by themselves or part of a "flock." They have been used extensively in the low-Earth orbit, providing a low-cost means for universities and institutions to carry out experiments in this microgravity environment. As cubesat technology is maturing, so does the scope of their application.
So, as NASA steps up its plans for the Europa Clipper concept to visit the icy Jupiter moon, JPL has asked for cubesat proposals from universities that could complement the primary Clipper payload. As we have a mission going to Europa, why not attach some cubesats for the ride?
NASA has outlined some key science objectives these axillary cubesats should be able to carry out, including "reconnaissance for future landing sites, gravity fields, magnetic fields, atmospheric and plume science, and radiation measurements."