Interplanetary navigation and trajectory planning (Score 1)

Your source at NASA Johnson Space Center may use "simple" Newtonian physics, but please remember, NASA JSC has not executed a trajectory to Mars or any other planet. The NASA focus of expertise in interplanetary navigation is NASA Jet Propulsion Lab (JPL), affiliated with Caltech. Here is a useful link: A chapter on spacecraft navigation from JPL's "Basics of Spaceflight" http://www.jpl.nasa.gov/basics/bsf13-1.html A search on JPL's home page will yield numerous references to navigation and trajectory information: http://www.jpl.nasa.gov/ Navigation generally involves several course corrections along the way. There are early burns to correct the trajectory after launch, another possibly at the midpoint, and one or more final burns for orbital insertion or landing ellipse targeting.