9 ms·
> 1 second launch window Why is it so precise?
by swhitt 11y ago
> 1 second launch window
Why is it so precise?
- JshWright 11y agoThey need to launch when the orbital plane of the station is directly overhead. The earth rotates surprisingly quickly, so even a minute or two later the plane of Dragon's orbit would be far enough off from the plane of the station that a couple expensive inclination change maneuvers would be necessary to line them up again.
- rgbrenner 11y agoThe earth rotates surprisingly quickly Not so much the earth as ISS. The earth rotates at 24900mi/day or about 1040mph. The ISS, to maintain its orbit, travels at 17150mph or about 5 miles per second. So in two minutes, it travels about 600 miles.
- ohazi 11y agoYeah, but the window is short because you have to catch the orbital plane, not the ISS itself. Earth's rotation speed is the relevant number here for figuring out how fast that plane sweeps across the sky.
- trose 11y agoWhile it's possible to inject the dragon capsule anywhere and get it's orbit in line with the ISS, its much more economical to inject it really close to the ISS so they dont need to do as much work to finish the trip.