Orbital Planetary Assault
Orbital planetary assault by infantry troops is a concept only a few space faring civilizations ever considered and even fewer have dedicated units to do so. No other Civilization known has developed it to such an extend as Terran Forces and then translated it into Union Military tactics and warfare
Among the civilizations that do Planetary assaults by dropping troops from orbit are the Nul, the Perharians, the Botnaars, the Y'All and of course Terrans. (none of the currently known Galactic Council species do Planetary Assaults this way)
Terrans used this form of combat from the first years of their ascent and have been the driving force creating the United Stars Marine Corps and the Orbital Assault Units of the United Stars Army. The Union Marine Corps has perfected the art of Planetary Assault over the many centuries into a fine tuned art form that is perhaps the most feared form of attack by all Union Enemies. The very idea of heavily armed soldiers dropping from the skies to take a planet by force is very intimidating.