Are there any active duty Army or Navy officers who completed an on campus doctorate degree while serving? Is it even possible?

I'm not active duty anymore, but I did complete a PhD when I was on active duty. I was selected through a competitive board process, and I had a PCS assignment to attend school (that was my duty assignment for three years). I completed all of the coursework and my comprehensive exams during my three years on campus, and then finished the dissertation at my follow-on assignment. In total, it took me ~6 years, but I know a number of officers who completed it in a shorter time frame. The key is going into the doctoral program having a good idea of what you want to do your dissertation on, and then having access to the necessary data. Also, I was in the Army Medical Department. Civilian schooling is one of the best-kept secrets of the Army Medical Department, but other branches also have great opportunities.

A now deceased friend was a McNamera selectee for a PhD degree while serving as an Air Force Officer. Stationed at Wright Patterson, he would check out an airplane and fly to research destinations as a qualified 0-6 pilot. Jack was a Navigator early on in WW II and only needed to complete 25 missions to return CONUS - for good; he did not have to return to Britain for a second tour.

That would be near impossible. The only way you would be able to do is if you were to into a military program that lets you go to school but then you return to the Army. I know a lot of medical officers do this and then they return to the Army as a medical officer with a hefty commitment.