The communication attempts were unsuccessful and on 2 February 2020 NASA announced Mars Cube One mission formally ended.

[8] Mars Cube One is the first spacecraft built to the CubeSat form to operate beyond Earth orbit for a deep space mission.

[10] The two Mars Cube One spacecraft are identical and officially called MarCO-A and MarCO-B and were launched together for redundancy; they were nicknamed by JPL engineers as WALL-E and EVE in reference to the main characters in the animated film WALL-E.[11][12] The MarCO mission cost was US$18.5 million.

[13] JPL's MarCO engineers view the Mars flyby as a technology demonstration that could lead to many more low-cost, targeted small satellite missions outside of Earth's orbit.

[14] While keeping an eye on the performance of the MarCO mission, NASA has proposed spending more money on CubeSats as a complement to multi-billion-dollar projects which sometimes face years of delay.

The launch was scheduled for 4 March 2016 on an Atlas V 401,[16] but the mission was postponed to 5 May 2018 after a major test failure of an InSight scientific instrument.

[22] The MarCO spacecraft were launched as a pair (named WALL-E and EVE for the movie characters) for redundancy, and flew at either side of InSight.

In addition to serving as communications relays, they also tested the CubeSat components' endurance and navigation capabilities in deep space.

Seeing the already-present difficulty in communicating with ground control during especially risky situations, various teams set out to revise the way in which data is relayed back to Earth.

For the CubeSats to relay information, they need a high gain antenna (HGA) which is reliable, meets the mass specs, has low complexity, and is affordable to build.

Engineers expected them to keep working for a couple weeks after they pass Mars orbit, depending on how long their propellant and electronics last.

[13] Each MarCO carries a softball-sized radio used to communicate with the ground using X-band, to receive data from InSight using UHF, and to collect tracking measurements for navigation.