Description from original post (created 2012-06-07 15:04):
"Similar to the original IRON project, the SPARTAN-IV Program would only consist of adult volunteers, as opposed to young children (however, it was successful). When the Program was started, the surviving members of the previous generations were offered to be integrated into it, though it's unknown how many exactly accepted/declined. The first active SPARTAN-IVs were already deployed by 2553, as some of them were temporarily assigned to the UNSC infinity before it was scheduled to launch."