Earth-to-Moon Journey Simulator
Change the assumed path length and travel time to compare the average speed implied by different lunar journeys. The result is intentionally separated from spacecraft velocity because a real transfer accelerates, decelerates and curves under gravity throughout the flight.
Why travel time is a mission-design choice
There is no single Earth-to-Moon travel time. A trajectory can trade time against launch energy, spacecraft capability, arrival geometry and operational constraints. Some missions use relatively direct translunar trajectories, while others deliberately take lower-energy or multi-body paths that require much longer flight times.
What average speed means here
The calculator divides the entered path length by the entered elapsed time. That is useful for comparing journeys, but it is not the speed a spacecraft must hold. Real spacecraft follow curved trajectories. Their velocity changes because of Earth gravity, manoeuvres, lunar gravity and, for some trajectories, significant solar perturbations.
Try these comparisons
- Keep the distance fixed and compare 3 days with 30 or 90 days.
- Increase the assumed path length while keeping travel time constant to see how the average rises.
- Compare the journey duration with the light-time result to see how much faster electromagnetic communication is than physical travel.
Limitations
This is a comparison and teaching tool, not a trajectory optimiser. It does not solve a Lambert transfer, integrate an n-body trajectory, determine launch windows or calculate required injection energy. The lunar delta-v planner covers propulsion-budget trade-offs separately.
Further reading
NASA Technical Reports Server: Artemis Lunar Mission Availability & Design