Part 5/11:
On average 41 million kilometers away, Venus seems ridiculously close, yet reaching it often takes nearly 300 days depending on the trajectory. The infamous Venera missions by the USSR in the early 1960s marked the beginning of intense exploration, but subsequent missions experienced extended travel times mainly due to Earth and Venus’s relative positions in their orbits.
Gravitational Mechanics
When planning a trajectory to Venus, launch windows and the timing of planetary alignments greatly influence mission design. To reach it during optimal conditions, one needs to account for the differential speed of the two planets. In practice, this means that the spacecraft must follow an elliptical trajectory to intersect Venus orbit accurately, further complicating the flight path.