CubeSats are nano classed satellites, designed to be small (10cm x 10cm x 10cm) and inexpensive to make. Their size lets them hitch a ride up to space with other missions from where they can be deployed. This lowered the cost of entry significantly and enabled companies & research teams to carry out their ventures in space.
Astrobotics & Carnegie Mellon University are taking this idea to planetary exploration with the Iris - a pint sized rover made to withstand the harsh conditions on the moon. Where previous rovers were built like a tank, cube rovers will be about the size of a shoebox with a much cheaper cost of production.
In 2021, the Peregrine lander will take off for the moon with a cargo load of CubeRovers including the Iris. Once on the moon, the squad will do what they do best - rove along the moon, capturing data and images of the moon surface. If all goes well, we could see miniature robots being a part of every space mission.