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To: Jack Hydrazine

I believe SpaceX will only achieve low Earth orbit.


9 posted on 07/20/2010 10:02:49 AM PDT by Elderberry
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To: Elderberry

A spacecraft on orbit around the Earth can also be sent to the moon. You just send up more fuel for its rocket motor. Such a spacecraft need only add a little over 4 km/sec of velocity to its orbital speed of 11.86 km/sec to break away from our planet and travel in a free trajectory to the moon.

In any sort of rocketry, getting from Earth’s surface to space is the hard part. This is why rockets use heavy, high-thrust chemically-fueled engines to lift off and boost into orbit. Once you are in space, however, high thrust only reduces travel time; it is no longer a necessity for navigation. An amount of thrust equivalent to that produced by a butterfly’s wing applied over time is enough to get a million-ton spacecraft to Saturn. As the late Robert Heinlein once said, “An object on orbit is halfway to anywhere.”


17 posted on 07/20/2010 10:39:47 AM PDT by B-Chan
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To: Elderberry

And what makes you think that SpaceX is bound only for LEO when their goal is to get to Mars?


22 posted on 07/20/2010 11:06:13 AM PDT by Jack Hydrazine (It's the end of the world as we know it and I feel fine!)
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