NASA launched a pair of spacecraft that were very small, about the size of a paste, collectively known as Marco last year. NASA knew when the spacecraft launched that they would be pushing the boundaries simply by operating in deep space, and their success was measured in terms of survival. The MarCo mission (short for Mars Cube One) was the first interplanetary mission to use small CubeSats.
The pair of spacecrafts was named after EVE and Wall-E, after characters from the popular Pixar film. MarCO was launched on Mars behind the InSight mission and was intended to serve as data relays during each stage of the InSight landing process in near-real time, and this mission was a success. One of the great features of the Marco spacecraft was that they were much cheaper than most space missions that cost $ 18.5 million. NASA now says that the spacecraft Marco has stopped communicating and it is assumed that we will never hear EVE or Wall-E again.
Wall-E's latest announcement was received on December 29 with the latest FSC announcement received on January 4. Data from the trajectory suggests that Wall-E is more than 1 million miles from Mars, with EVE nearly 2 million miles from Mars. As for why communications have stopped, NASA has some ideas.
Wall-E had a stuck propeller, and attitude control problems could cause it to oscillate and lose the ability to send and receive commands. Another possible problem would be some kind of flaw with the brightness sensors that allow the spacecraft to point to the sun to recharge.
Nasa has another chance to communicate with the Marco spacecraft this summer as the pair begins to approach the sun and the potential to gather energy to charge the battery grows. Even though NASA never hears from EVE or Wall-E again, they consider the MarCO mission a success.