Here are the people who do this for NASA planetary missions: http://ssd.jpl.nasa.gov http://ssd.jpl.nasa.gov Here's a snapshot of object locations in the inne

Here are the people who do this for NASA planetary missions: http://ssd.jpl.nasa.gov http://ssd.jpl.nasa.gov Here's a snapshot of object locations in the inner solar system: http://ssd.jpl.nasa.gov/?ss_inner http://ssd.jpl.nasa.gov/?ss_inner There are a lot of challenging problem areas: rendezvous with small bodies (very irregular gravity fields), mission trajectory design, operations planning for flybys in the presence of, say, camera pointing constraints. (@lutusp knows this already -- I'm putting it here just for interest.)