Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Gravity affect rotation?

  1. Dec 9, 2006 #1
    I think this is an aproriate forum to ask this, I'm curious to the effect a planets gravity field has on a rocket flying past.

    I know it would simply pull in the object harder the closer it gets to it, but does it affect the rotation of the rocket as well? If one slingshots around a planet would the rocket always point the direction it was going in, or would it simply move around the planet in it's original orientation?

    I need this info for a game I'm working on, but I found I'm not actually as familliar with gravity as I always thought I was... :wink:
     
  2. jcsd
  3. Dec 9, 2006 #2

    SpaceTiger

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    There are small tidal effects caused by the fact that the planet will have a stronger pull on the near side of the rocket than the far side. This can apply a torque and change the rotation rate. However, in most realistic scenarios, this force would be far too small to be noticable. It's only important when the length of the rocket is comparable to its distance to the planet.
     
  4. Dec 9, 2006 #3

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    That is not correct. The gravity gradient torque is a significant effect in low Earth orbit. The Space Station is typically in "torque equilibrium attitude", the spacecraft attitude in which the gravity gradient and aerodynamic torques cancel one another.
     
  5. Dec 12, 2006 #4

    SpaceTiger

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?