Pathfinder Technology Demonstrator
NASA's Pathfinder Technology Demonstrator (PTD) Project is a series of tech demonstrations of technologies aboard a series of nanosatellites known as CubeSats, providing significant enhancements to the performance of these versatile spacecraft. Each of the five planned PTD missions consist of a 6-unit (6U) CubeSat with expandable solar arrays.
Source: Wikipedia — Pathfinder Technology Demonstrator (CC BY-SA 4.0)