This is a photo of the soyuz capsule posted by the asker of a previous question. One of the labels reads "Not to stand near this side". What is the reason for this? Is it because of active ionizing or RF radiation sources on that side? Or a caution against the possibility of yet not fired retro rocket?

enter image description here

  • $\begingroup$ My first thought was residual heat, but I guess the heat shield itself has been jettisoned by this point, so the next most obvious concern would be one of the retros firing late due to malfunction. It seems odd that the bystander instructions would be on the bottom, since I'd expect it to normally land bottom-down (unless the chute positioning is specifically designed otherwise). $\endgroup$ Nov 15, 2015 at 20:54
  • $\begingroup$ @RussellBorogove i believe it usually lands and then tumbles a few times. $\endgroup$
    – kim holder
    Nov 15, 2015 at 21:45
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    $\begingroup$ This page by Sven Grahn postulates it might be due to "radiation from the gamma-ray sources that are used as 'transmitters' for the backscatter 'altimeter' that triggers the soft-landing retro-rockets". $\endgroup$ Nov 15, 2015 at 22:13
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    $\begingroup$ Also, this document gives some insight about the dangers around the landed capsule. $\endgroup$ Nov 15, 2015 at 22:15
  • $\begingroup$ @Bryan Lynch great finds ! $\endgroup$
    – Kamen N.
    Nov 15, 2015 at 22:48

1 Answer 1


The original wording above says "Do not stand in front of the bigger head". Two reasons:

  1. There is a Kaktus precision gamma-ray altimeter (Containing 60Со or 137Сs).
  2. There is a chance of one of the soft landing engines firing late due to malfunction.

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