Adding customization to rocket engines such the length, exit diameter, and curvature of the engine bell allowing for more accurate recreation of historical rockets.

Also implementing a mechanism by which they length and width impact engine performance (Isp can be calculated the exhaust escape velocity divided by gravity plus a constant multiplied by the difference in pressure at the nozzle exit and the ambient air pressure, the internal pressure can just be solved from a simple algebraic general solution which is all done in my forum post on the topic). Options of prefab parts optimized for different environments then the ability to, if the player chose, modify the engine bell to optimize it for various environments, for example a lander for some other planet with a different ambient air pressure then the earth analog would have an engine bell optimized for its particular environment.

A planetary information window giving us details on sl pressure (sea level) for the different bodies would give players more opportunities to make craft for more specific tasks as well as provide the opportunity to learn a little about rocket plumbing, which is so tragically overlooked in games.

Original forum post: https://www.simplerockets.com/Forums/View/1074/Engine-Customization