The Spartan-IV program was the third successful Spartan training program and the first since the end of the Human-Covenant War. The second Spartan-IV Class began augmentations and training in 2554, and was much larger than the first class size of 145. Spartan-IV candidates received their augmentations on a facility on Mars, and trained on a top secret orbital space station. The Spartan-IV program is known for being the first Spartan program to use volunteers instead of recruiting or kidnapping children, as was done in the Spartan-III and Spartan-II programs. The Spartan-IV program is headed by former Spartan-II Musa-096 and former Spartan-II Jun-A266.