Dr. Owen was a human scientist stationed at Galileo Base.
When Galileo Base was under attack from the Covenant, she send out a distress call to UNSC forces. So Sarah Palmer dispatched Fireteam Crimson to help defend the base. After the foces were defeated, Owen helped getting the base up and running again.[1]
When the base was under attack for a second time she explained to Fireteam Crimson that base defenses were down due to Dr. Alexander and that he used the power of the defenses to activate his mini-reactor.[2]