Astronomy
The Orbital Mechanics Behind Interplanetary Travel
Quick fact
A Hohmann transfer orbit to Mars takes about 259 days with current propulsion, but a gravity assist from Venus can shorten the trip—though it may also extend it depending on the mission design.
Why this is interesting
Every rocket launch to another planet is a precise dance with gravity, not a straight-line chase. Why do spacecraft take looping paths across the solar system instead of aiming straight at Mars?