At the start of the game you fly out from the assembly shop into the Rock Sector and your first task is to get to the Main base. After you did that, two identification options will be offered by the building: the first option is to name your mechmind by your own and the second option lets the main base decide which name you will get.
As long as you don’t take any of these options you will get called as "Unnamed" by everyone. If you pick the second option you will get this name from the Main Base.
- The "5" and the "001" in the name probably stand for the 1st mechmind of the fifth generation, as the name is built in the same way in the sequel.