Has the Roche limit affect been observed having an effect on an constructed object gravitational wise to cause damage? Could the Roche limit be used to slow an object?

  • $\begingroup$ Is your question about spacecraft? Or about moons? Or should you rather ask 2? $\endgroup$ – J. Chomel Feb 25 '17 at 7:05
  • $\begingroup$ I don't think this is answerable: The body doesn't match the heading. The "How long" question depends on many factors. There is another question "What happens to the debris if the moon is struck" and a third "has the effect been observed". Please only ask one question at a time. $\endgroup$ – James K Feb 25 '17 at 8:05
  • $\begingroup$ @JamesK edited it for you. $\endgroup$ – Muze Feb 25 '17 at 8:17

No. The Roche limit refers to the radius at which a satellite which is held together only by its own self gravity is disrupted by tidal forces. Spacecraft are not such satellites, but are much harder to tear apart.

  • 2
    $\begingroup$ You could calculate an orbital distance at which a solid steel sphere would be tidally disrupted, but it'd probably only apply to neutron stars and the like. $\endgroup$ – Wayfaring Stranger Feb 25 '17 at 20:25

You have asked two different questions, Muze. The title of your question asks whether the Roche limit is dangerous to spacecraft, but the body asks whether the Roche limit has been observed having an effect on an object. The answers to these two very different questions are "no" and "yes".

The main question first: The Roche limit applies to objects that are weakly bound by self gravitation. A good example was Comet Shoemaker–Levy 9, which broke apart into a number of pieces before colliding with Jupiter in 1994. A prior close approach to Jupiter in 1992 tore the comet into pieces thanks to tidal effects. The collision in 1994 was a string of pearls hitting Jupiter.

Spacecraft are held together via welds, nuts and bolts, screws, and inter-atomic and inter-molecular forces. Each of these is many orders of magnitude stronger than is gravitation. The Roche limit doesn't apply to spacecraft as spacecraft aren't held together by gravitation.


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