The Settled Systems is no stranger to warfare, and if ther's one thing armed conflict relies on it's trained warriors with guns and guts. You had both. Simple, bloddy work... and you were great at it.
Starting Skills
Fitness
In space, the greatest commodity is oxygen, and the increased lung capacity gained by a regular physical fitness regimen is essential to survival.
Ballistics
Centuries of conflict have proven that when it comes to threat elimination, few things stack up to the reliable power of high-speed projectiles.
Boost Pack Training
Specialized training and innovations in personal mobility systems have allowed for unfettered exploration on alien worlds.