More ODE and expanding the model

I spent some time expanding the console to do the RCS control, but also started to add some convenience functions such as Stop Rotation, and Set Angles. They are kind of cheats in a way since I just reset the values in the model as oppose to writing feedback control loop code, but I just couldn’t write PID controlers for this. Too much work, and I am not really interested in that much realism.

One thing that I am starting to tackle is the auto-pilot functions. The two functions mentioned above are a start, but a key operation is to navigate from one point to another, and this is fairly complicated (particularly for long distances) since it requires a period of acceleration followed by deceleration. If there is no limit to fuel then it is pretty easy since you just accelerate for half the time and decelerate for the other half. If you only want to use a certain amount of fuel then you have to figure out how much thrust over time consumes what amount of fuel and then split it across the Acc and Dec stages of the trip, and figure out what the coasting period is. It is pretty amazing how fast you can get going under one G of acceleration. A trip to the moon only takes about 6 hours! However you need either a very efficient engine or a lot of fuel, (which kills your acceleration factor). At the moment I am thinking about whether to do scripting or just provide a trip calculator of sorts that tells the pilot how long to burn at a particular rate, how long to coast and when to start deceleration.

Finally I read about the Vasimr engine under development by NASA. [ Wikipedia] has information about it, and you can also read about it from the company that is working on it: [ AdAstra Rockets]. The engine looks cool enough to play with modeling a simplified version. In reality the main problem seems to be that they will need a nuclear reactor to power the thing, and having nuclear material in space has always been a very touchy subject. Nobody wants to take a chance of the material getting scattered if there is an issue on launch or a situation like the satellite that they had to shoot down.

This area has been good for me in expanding my knowledge of things like specific impulse and how that translates into thrust. Perhaps more on it when I am clearer in my understanding. For now this gives me plenty to work on.