In the Halo universe, the main character is John-117, commonly referred to as "the Master Chief", a non-commissioned officer even though he had a lifelong military education. Why hasn't he become a commissioned officer?
This actually goes beyond him. There are a couple of Lieutenants, but that is all.
Is there any reason for having so few officers in the Spartan-II program?
Flippant answer: because he works for a living.
Officer-ship is not a reward. It's a different set of jobs entirely. To grossly oversimplify: enlisted men are the workforce; non-commissioned officers are the foremen; and officers are the managers.
As a Master Chief Petty Officer, the Master Chief has authority over most other enlisted and NCO personnel. Most officers--the smart ones who want to live to see tomorrow, anyway--will also seek out and listen to his advice, even if they do outrank him, because you don't get to be a MCPO without at the very least being an expert in your specialty.
It's not unknown, in real militaries, for an enlisted man to work up through NCO and eventually do the necessary course work and paperwork to be considered for a commission, of course. But it's not an automatic progression, either.
There were a few Spartans that were discharged for various reasons from the Spartan program. These, through their work primarily in ONI, achieved higher ranks than the "operational" spartans. Examples: Rear Admiral Serin Osman (Serin-019) and Lieutenant Commander Fhajad-084. Additionally, Colonel Randall Aiken (Randall-037) went missing and became stranded during an operation and ended up joining the colonial guard, rising through the ranks as a discharged Spartan.
There were a number of "full Spartans" that made it all the way through the initial Spartan-II program, including surviving augmentation.
In today's military, especially in the world of special operations, battlefield command is held by a junior grade officer (an Ensign, Lieutenant (Junior Grade), or Lieutenant), or by an NCO. The need for technical expertise throughout the small squads operators complete their missions in mandate that all members be proficient in the operational skillsets. As such, officers, who generally put an emphasis on leadership throughout their training, are often not skilled enough to prevent the team from being weighed down by them, especially as they reach the higher ranks. In addition, higher-ranked officers are often too valuable from a strategic standpoint to risk in front-line combat.
The fact that the Spartans were so skilled in such a wide variety of areas enabled them to command tremendous respect, both from their legends and from those who saw what they were capable of. As such, they mostly remained enlisted personnel. A few were promoted to higher enlisted ranks (like John-117), but for the most part, the Spartan-IIs seemed to stay at Petty Officer 2nd Class.
There was a marked change with the Spartan-III program. Kurt-051, the Spartan-II in charge of the training for the Spartan-IIIs, was given an officer rank so as to make the chain of command clear. When he was no longer able to supervise the remaining forces under his command, he promoted Fred-104 to the rank of LTJG to set up a clear head. As for those in the Spartan-III program, they seemed to hold markedly higher ranks. The members of Noble Team: Commander Carter-A259, Lieutenant Commander Catherine-B320, Warrant Officer Emile-A239, and Noble Six, a Lieutenant. Jorge-052, a Spartan-II was granted his Warrant Officer rank due to his membership in Noble Team.
The article on Noble Team gives this reasoning for their higher ranks:
Noble Team also operated with non-Spartan military personnel more extensively than other Spartan teams. To grant them more operational freedom when interacting with military personnel, the members of Noble Team had been given higher ranks than most Spartans by their CO.
And that may be why the Spartan-IIs were not given higher ranks - simply, because since they were used as secretive commandos, they operated outside the normal chain of command and did not need the more formalized rank structure.
The highest rank for conscripted soldiers (like most early Spartans,John falls into this category) in the halo universe is master chief petty officer, so he is at the highest rank he can achieve .
The reason why Sierra-117 is not an Commissioned officer is first off he never went to OCS(officer candidate school) and it was so that he didn't cause turmoil in the ranks, as if he were a Officer in the Navy (Lt) he would have never had to have obeyed SgtMaj Johnson, even though Johnson is of E-9 in the Marines and Sierra-117 is of E-9 in Navy(master chief petty officer)
So yeah mainly because he never had OCS. :p
