I was quite surprised to read in this question one very interesting detail about the system used for Saturn V launch release. Saturn V employed a system of pins and dies such that when the hold-down arms released, the first few inches of initial motion drew tapered pins through extrusion dies. This had the effect of damping the shock of launch release (from 0 to about 1/6 g).

Has either this specific technique or some other means to achieve the same purpose been used on or proposed for any other launch system? If not, was this done out of an abundance of caution in the face of unknowns, or was it found/known that without this measure, things would indeed break?

  • $\begingroup$ Just to make sure - you are distinguishing this controlled release mechanism from a hold-down mechanism? $\endgroup$ Commented Sep 29, 2019 at 16:14
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    $\begingroup$ @OrganicMarble Yes, specifically the mechanism that acted over the first few inches of motion to convert essentially a step-change in acceleration to something more gradual (pin/die, in the Saturn V case). $\endgroup$
    – Anthony X
    Commented Sep 29, 2019 at 19:24
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    $\begingroup$ When I asked the linked question, I was equally surprised about this mechanism. I'm also curious to know if it was/is a commonly used mechanism. It's beautiful in its simplicity. $\endgroup$
    – Ludo
    Commented Sep 30, 2019 at 6:51

1 Answer 1


This question has been intriguing me for a long time and I can't find a definite answer. So far, from what I've found, the answer is "no".

For the most powerful launchers, I found the following information:

From one of the references in this answer I found though that while SLS is free-standing, it is bolted during transport. This was a change with respect to STS:

Currently, it is expected that the VSPs will be static, providing a weight-of-vehicle-only support pedestal for the SRBs – with a Ground Support Equipment bolt inserted through the VSPs and SRB for rollout operations stability only.

For comparison, the corresponding component for the Space Shuttle saw the support posts provide hold-down support for the Shuttle vehicle, terminating at T-0 with the detonation of NASA Standard Detonators to explosively severe the hold-down bolts and free the Shuttle’s SRBs from the pad.

So the bolts holding down SLS during transport will be removed pre-launch, while during the Shuttle these bolts were severed at launch. Organic Marble (the resident STS expert) states in this answer that the STS could pull the bolts free, but with major impact on the trajectory, so they were not intended to be a release mechanism.


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