The Spartan Project: (excerpt from CAA FACTBOOK [l.update. 5.21.2547])
The members of the Spartan Program are elite military operators recruited from all corners of UNSC governed space. Each of them is a highly decorated veteran with literal decades of combat experience and an unwavering commitment to the defense of mankind. In order to aid them in their goal, they are armed with the absolute bleeding edge in military technology--the Mjolnir powered assault armor.
More to the point, the Spartan super-soldiers are the only men and women alive with the extensive training and physical wherewithal necessary to harness the full potential of this highly specialized equipment.