This costs 5,000 Element Zero though, so you probably won’t be able to do it after each mission. You can only have one bonus power active at once, but you can research Advanced Training over and over again if you want to, switching out the power each time. Related: Mass Effect 3: All Consequences Of Mass Effect 2's Suicide Mission
Once you complete each of their loyalty missions though, you will be able to research their bonus power via Advanced Training in the Tech Lab. That’s because the Advanced Training research relies on squadmate loyalty, and immediately after Horizon, none of your squad will be loyal. This is a research project that becomes available after completing Horizon, although immediately after Horizon, it is useless.
However, throughout Mass Effect 2 Shepard will also be able to unlock a bonus power via Advanced Training.
Commander Shepard has a wide variety of powers available in combat throughout Mass Effect, with different powers available depending on whether Shep is a Soldier, Adept, Vanguard, Engineer, Sentinel, or Infiltrator.