Traitor Tad lives in a universe in which many nationalities and many military services have contributed to the organization and traditions of the space forces. You will find a complex array of military units and equipment.
In particular, space combat is largely conducted in a solar system, and most combat is conducted either in orbit or on planetary surfaces. The space forces transport military forces to the planet, and these forces then invade and occupy. The space fleet uses largely naval traditions, but also transports units of the regular army, a wide array of special forces, a surface navy (to deal with the seas of the conquered planet), regular army units for large scale land combat.
Roles overlap, but organizational turf is jealously protected. The story Traitor Tad: A Real Battle introduces the regular army’s armored battalion and brigade, and of course these involve smaller units. The brigade in question operates independently, though reporting to a divisional headquarters.
Tank Platoon: 3 Main Battle Tanks, one of which is specially configured for command. It still carries the same main armament, but less anti-personnel weapons.
Tank Company: 4 platoons, plus a combined HQ and Support platoon, which consists of one command configured MBT and four smaller armored personnel carriers.
Tank Battalion: 3 companies + a similar headquarters and support company which will include about a platoon of mounted infantry
Tank Brigade: 5 Tank Battalions
Tank Division: 3 Tank Brigades.
Everything up to the brigade level is required to be mobile so the headquarters is entirely housed in vehicles. They can establish camp and may set up other housing and work space, but they are supposed to remain as completely mobile as is possible–and it is possible for them to remain very mobile.