(Related: How expensive would it be to make a spacecraft that can survive leaving an Earth suffering from Kessler Syndrome?)

Kessler Syndrome is a theoretical scenario in which the density of objects in low Earth orbit (LEO) is high enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions.

It is sometimes described in what sound like sensationalistic terms as something that could easily get so bad that it would straight-up prevent any future space-flight. I find myself skeptical of this, given that it would take a LOT of debris (which also must be large enough to pierce at least a trivial layer of armor) to provide unmanageable risk for a rocket that is passing through the LEO debris shell to a higher orbit (or to Earth orbit escape) in a matter of minutes.

Currently, the highest density of space debris is in a shell that starts at an altitude high enough that decay due to atmospheric drag is too slow, and ends at the upper edge of "lower" earth orbit (as far fewer satellites are launched to higher altitudes). This isn't a particularly large shell, and it seems like what makes satellites impractical over a period of months is very different from what seriously imperils a rocket that passes through in a few minutes (and might still have its payload fairing in place, since the majority of dV is expended in horizontal thrust, not vertical.)

  • $\begingroup$ I understand your reasoning though, currently, the question as written at present isn't an easy fit for Space StackExchange. It might help to break it into two or three more specific questions. As an example, how would it feel if the answer given now is just "it depends what rate we continue to launch things and for what timeframe you are interested in"? The question also requires the respondant to assume a value judgement of unmanageable risk. $\endgroup$
    – Puffin
    Sep 21, 2019 at 10:20
  • 4
    $\begingroup$ Disagree with the close vote, this question seems fine. $\endgroup$
    – Ingolifs
    Sep 21, 2019 at 21:03
  • 2
    $\begingroup$ This is a duplicate of several answers on this subject already. The short answer is that the Kessler Syndrome is about threats to objects that stay in LEO for years. A rocket passing through is only going to be in a dangerous zone for a few minutes, and the risk of collision between it and some debris even in an extreme Kessler Syndrome scenario is miniscule. $\endgroup$
    – Dan Hanson
    Sep 21, 2019 at 21:24

1 Answer 1


No at least not in the foreseeable future.

As is pointed out in the comment the time spent in the LEO shell is many orders of magnitude higher for a satellite that is designed to stay in LEO, than one then just punching through. Hence for the density of debris in LEO to cause significant concern for passing craft would be required to be many orders of magnitude higher than that safe for LEO operation. Assuming that we stop launching satellites to LEO once its pointless because they won't last, the only way the much larger amount of debris could be created is if the existing debris broke into much smaller pieces. This would take long enough that the orbits in LEO would start to decay.

In higher orbits this may eventually become a problem, but we are a long way off that.


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