Nothing is known about her early life apart from that at some point she enlisted in PROJECT PEGASUS and was transferred to Fireteam Delta.
PROJECT PEGASUS Service
Assassination of Alexander Mage (11th October 2609)
Kat Archer along with fellow Pegasus trooper Andrew Thomas Moa were sent to eliminate the rebel leader Alexander Mage who belonged to the group known as The Rights Of The People. Moa and Archer successfully killed there target.
OPERATION CASKET (15th November 2609)
Kat Archer along with the rest of Fireteam Delta were sent to respond to an SOS on the planet Yourmat. After arriving the team found that the signal was being sent from an abandoned UNSC rig captured by scavengers, Captain Sam Dustbin tried to respond peacefully but the scavengers attacked anyway.
After clearing the area the team recovered a CRYO pod that was broadcasting the signal.
OPERATION MEATGRINDER / Death (18th November 2609)
As a follow up to OPERATION EYE SPY all members of Fireteam Delta took part in an operation to eliminate The Rights Of The People once and for all, although the mission would be a success only Moa, Fredrick Derick Bucket, Susan Hawk and Russ Vovolsky would survive.