With the success of the past Spartan projects, ONI commissioned the Spartan IV Program. The Spartan IV Project was originally to be headed by Colonel James Ackerson and Doctor Catherin Halsey. This did not happen due to Ackerson’s death and Halsey becoming ONI’s scapegoat who was arrested after returning from Onyx.
Like the original Spartan program, ORION, the Spartan IV Program utilized consenting Adult volunteers from the original four UNSC Defense Force branches. Eventually the Spartan IIIs that survived the Human-Covenant war were allowed to be integrated in to the new program.
These new soldiers were successfully augmented such as the Spartan IIIs were, without the need of children and hormone
treatments. These super soldiers were then given new Mjolnir Mark VII armors and experimental new weapons.