An artist's concept of one of NASA's MarCO CubeSats. (NASA/JPL-Caltech)

NASA has achieved a first for the class of tiny spacecraft known as CubeSats. The MarCO-A and MarCO-B CubeSats are designed to trail InSight on the way to Mars, aiming to relay back data about InSight as it enters the planet's atmosphere and attempts to land.

The MarCOs were never intended to collect any science data; instead, they are a test of miniaturized communication and navigation technology that can blaze a path for future CubeSats sent to other planets. They have already traveled farther than any CubeSat before them.