– NASA’s latest Mars explorer has company all the way to the red planet: a couple of puny yet groundbreaking sidekicks.

Named after the characters in the 2008 animated movie, the small satellites WALL-E and EVE hitched a ride on the Atlas V rocket that launched with the Mars InSight lander. Similar in size to a briefcase or large cereal box, the satellites popped out from the rocket’s upper stage after liftoff and are high-tailing it to Mars, right behind InSight.

This is the first time little cube-shaped satellites, CubeSats as they’re known, have set sail for deep space. The journey will span 6½ months and 300 million miles.

Miniature satellites, or CubeSats, have been piggybacking on big-ticket space missions for well over a decade, but have been confined to Earth orbit. That is changing with NASA’s Mars Cube One project, or MarCO, an $18.5 million experiment.

The cubes are equipped with the same type of cold gas propulsion system used in fire extinguishers to spray foam. In the movie WALL-E, uses a fire extinguisher to propel through space. Team members couldn’t resist the connection, thus the names WALL-E and EVE, after WALL-E’s love interest.

While InSight will stop at Mars on Nov. 26, WALL-E and EVE will zoom past. Besides testing the cubes’ maneuvering system, NASA wants to see if WALL-E and EVE can transmit data to Earth from InSight during its descent to Mars. Once past Mars, WALL-E and EVE will remain in an elliptical orbit around the sun, together for years to come. But they won’t work for long. Once they run out of fuel, they won’t be able to point their solar wings toward the sun for recharging.