I have been looking all over for the admin command that grants this ascension, and haven't found anything (all the others are known - see below)
Gamma: cheat playercommand Ascend1Beta: cheat playercommand Ascend2Alpha: cheat playercommand Ascend3Aberration Gamma: cheat playercommand AbAscend1Aberration Beta: cheat playercommand AbAscend2Aberration Alpha: cheat playercommand AbAscend3Extinction Gamma: cheat playercommand EXTAscend1Extinction Beta: cheat playercommand EXTAscend2Extinction Alpha: cheat playercommand EXTAscend3Genesis Part 1 Gamma: cheat playercommand Genascend1Genesis Part 1 Beta: cheat playercommand Genascend2Genesis Part 1 Alpha: cheat playercommand Genascend3Genesis Part 2 Gamma: cheat playercommand Gen2Ascend1Genesis Part 2 Beta: cheat playercommand Gen2Ascend2Genesis Part 2 Alpha: cheat playercommand Gen2Ascend3