Playing Kerbal Space Program, I wonder why they do several burns to get into orbit. Why can't a vehicle get smoothly to it, just pointing slightly off its course?
I saw a Soyuz launch at night from 1000 kms from Baikonur, faint exhaust was clearly visible, and it kept burning continuously, and got into an orbit. (At the cutoff moment, you could see a satellite-like moving star.) So, Soyuz get into in one single burn.
I studied the control theory (thanks for correcting my English), which solves problems like getting to some state by means of some parameters, and taking into account the trajectory. A problem like this is solved with a system of differential equations.
So, is such an optimal path smooth, or not? Is this difference just because of low precision of human flying by hand?