Launching into Polar Orbit

I have a question about your answer on launching rockets near the equator. Why do you say that launches into polar orbit are to the west instead of to the east like other launches?
- question from Jackson Lytton
In the previous question that you reference, we explained that most rocket launches are done to the east since this direction maximizes the beneficial speed bonus realized by launching in the direction of Earth's rotation. But if you want to launch into a polar orbit, which is rotating along a path that crosses the North and South Poles, you need to cancel out that speed bonus.

The explanation for this is pretty simple, actually. Ok, if you tried to launch exactly due north (0 deg. azimuth) to get into a polar orbit, the fact that you also have a small velocity component due to the Earth's rotation means you would still be launched into a slightly less than polar orbit. To visualize this, just draw one vector representing a due-north launch, and another one representing the Earth's rotation. Then just do vector addition. To counteract this effect, a spacecraft needs to launch slightly west in order to get into a true polar orbit.
- answer by Aaron Brown, 11 August 2002

Related Topics:

Aircraft | Design | Ask Us | Shop | Search