I'm not sure if most of you guys have already seen it, but I <b>highly</b> recommend the simulator Orbiter, available from
www.orbitersim.com . It's a free and highly detailed space flight sim, and you can try out a Mars flight yourself - either by working through everything on paper, or by downloading the TransX addon which lets you plot a course through various stages to take you on exactly the right path whether that's Hohmann transfer, hyperbolic or somewhere in between. You can even aerobrake into orbit on arrival and try to land at a specific point <img src="/images/icons/smile.gif" /><br /><br />As well as the main program, search Google for OrbiterSound and DeltaGliderIII - I'd consider these the "essential" addons for the program. It comes with various simulated craft (historical, realistic and fictional/easier to fly) including the STS but you can get updates for the Shuttles from other pages - it's possible to fly a complete satellite deployment or ISS docking flight right through to landing at KSC. There's even an incredible Apollo addon called NASSP, at
https://sourceforge.net/projects/nassp/ Although it's not quite finished yet, and as such is a bit tricky to install and set up, flying an Apollo mission complete with the original instrument panels and even a simulation of the Apollo Guidance Computer is just brilliant. The object of the developers is that eventually you should be able to fly the Apollo missions using the original '60s flight manuals and a few extra notes.<br /><br />Oh yeah and it's all completely free.<br /><br />Sorry to ramble on but I think most people here would be interested. Trigged, it can certainly do what you propose, from planning out all stages of the orbital mechanics right through to actually flying the thing.