When the dodos were underground they saw hundreds of robots controlled by some mysterious entity. After they returned, one of those robots appeared outside the base.
This was cause for concern until the crew observed its behavior, which was basically self-destructive. It wandered about the immediate vicinity, aimlessly running into various obstacles including the base itself.
After a few days the robot became the mission’s unofficial mascot, and the children on the orbiter were given the task of naming it. They suggested Humpty, which was met with general approval.
Despite its new status Samantha has forbidden bringing it through the airlock. Throughout the duration of the mission we’ve maintained the separation between the environments of Earth and Mars, for the protection of both worlds.
And so Humpty stays outside.