Star Trek Tactical Assault gives you a fair amount of control over the many things you can do with a star ship. And while the game doesn't go into the kind of detail that
Encounters does (balancing power levels between weapons and shields for example), there is still quite a lot to manage.
For the most part, you will just have to worry about the D-Pad for steering and the face buttons for firing your primary and secondary weapons and hailing or scanning ships. Since these are the actions you are likely to do more frequently in or just before a battle, it's a good thing these actions aren't hard to pick up. It's the other controls that make you stop occasionally and look in the manual for a reference.
The R button is overloaded pretty heavily , and when combined with other buttons, you will do a more complicated maneuver. R plus Square activates a warp while the same button plus Triangle, X or Circle will recharge your shields/cloak or overcharge your weapons and secondary weapons respectively. When used with the D-Pad, the ship will either get a boost when accelerating, stop quickly or make tighter turns. Thankfully, with the exception of the D-Pad functionality, most of these actions don't really need to be done in the heat of a battle and you won't have to pause and reference the book too many times while the Klingons are bearing down on you.
One aspect of the PSP version that gives it a leg up over the DS one is that you don't have as many menus or options to keep straight. On the DS, the entire lower screen is devoted to various things like crew alert status or information on your shields, navigation and weapons. And while it is good to have that kind of control, it was just too overwhelming and this version definitely simplified things a bit.
Star Trek Tactical Assault is a game made entirely for fans of the series, and of the original crew in particular. If you have never really gotten into Star Trek, then, as a ship-to-ship combat game, you might find Star Trek Tactical Assault lacking. Unlike games like Wing Commander or other similarly styled titles, you don't have a wide variety of weapons and you are firmly relegated to what the series has to offer, in both ships and capabilities. So ST fans are pretty much the only people who will be able to appreciate this game.