I remember reading (a long time ago in a library far, far away...) that, if Earth's gravity were that much stronger, the rocket equation (?) would mean that it were impossible to actually reach orbit from the surface given contemporary (chemical) propulsion.

I cannot for the life of me remember where I read it, or the exact numbers.

This came up again recently in a discussion on worldbuilding.SE. Can anyone give me a rough estimate of how strong a gravitational field could no longer be "escaped" to orbit given chemical propellants, making space exploration effectively impossible for the theoretical inhabitants of such a stellar body?

  • $\begingroup$ Note that "no orbit possible" is different from "can't reach orbit from the surface". $\endgroup$ Feb 13, 2018 at 9:40
  • $\begingroup$ @RogerLipscombe: Good point, clarified that a bit. $\endgroup$
    – DevSolar
    Feb 13, 2018 at 9:41
  • $\begingroup$ I (obviously) think this is a really interesting question. The answers and comments there show how well this site works when people work together to "get to the bottom" of a question, but finally @RussellBorogove 's answer puts reality to the exponential nature of the results of the Tyranny of the Rocket Equation as explained by astronaut Don Pettit. $\endgroup$
    – uhoh
    Feb 13, 2018 at 20:44


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