Re:SpaceX indicates it will manufacture the BFR rocket in Lo...
by dangerbird2 on Tuesday March 20, 2018 @01:49PM
(#16630850)
Rockets rarely launch at a retrograde (western) orbit because you have to overcome the earth’s rotation to reach orbital velocity, rather than the speed boost you get from launching with the earth’s rotation. IIRC, satellites launching from Vandenberg AFB in California take a polar orbit.
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Re:SpaceX indicates it will manufacture the BFR rocket in Lo...
by wongarsu on Tuesday March 20, 2018 @02:11PM
(#16631033)
Even if they went all the way up to the ISS's orbit (which would be useless both because it's a test flight and because they would be going the wrong direction), the difference between going in a western or eastern orbit is a ~10% difference in delta-v requirements. Normally that's an enormous difference, but if you can just decrease the size of the test payload at will it shouldn't matter much beyond spending a few thousand dollars more on fuel.
Re:SpaceX indicates it will manufacture the BFR rocket in Lo...
by isostatic on Tuesday March 20, 2018 @08:23PM
(#16634129)
It's not the height that counts, it's the sideways speed. Getting to 250 miles above sea level is relatively easy. Getting to 5 miles a second it far harder.
Re:SpaceX indicates it will manufacture the BFR rocket in Lo...
by isostatic on Tuesday March 20, 2018 @03:44PM
(#16631868)
But if you're not aiming for orbital velocity the earth's rotational speed doesn't make any difference -- the relative speed of start and end points are the same. It doesn't take more fuel to travel west than east because of the rotation of the earth (jet stream sure, but if rockets are affected by the jet stream there's something seriously wrong)
Disclaimer: my entire picture of orbital dynamics comes from KSP