The emphasis is firmly on realism, and the learning curve can be steep. Be prepared to invest some time and effort to brush up on your orbital mechanics background. Good starting points are JPL’s Basics of Space Flight, and R. Braeunig’s Rocket & Space Technology.
…
Improved physics: Gravity-gradient torque effects are now implemented. Vessels in low orbit will now experience torques as a result of their mass distribution. Orbiter’s model of angular motion has also been extensively overhauled.