I noticed what appears to be foamed-over cabling running roughly parallel to the systems tunnel on the exterior of the SLS Solid Rocket Boosters (SRBs). The cabling appears to run all the way from the forward to the aft skirt.

Highlighted in yellow here:

enter image description here

The shuttle SRBs didn't have this cabling:

enter image description here

Descriptions I've seen of the differences between the SRBs for the two vehicles didn't include this cabling. What is it for?

Image sources: SLS, STS


1 Answer 1


That is the new "systems tunnel" the runs up to the forward skirt avionics. This cabling is to connect the forward skirt avionics (where the majority of the avionics are) with the aft skirt TVC controllers and any sensors on the SRB stack. In addition any sensors that sent a signal to the orbiter aft through the Shuttle 17" disconnect would need to send that to the forward skirt. Better view with the cables exposed: https://www.nasa.gov/exploration/systems/sls/fs/solid-rocket-booster.html


See "systems tunnel":

https://ntrs.nasa.gov/api/citations/20150016519/downloads/20150016519.pdf https://ntrs.nasa.gov/api/citations/20200002334/downloads/20200002334.pdf

View of the STS Solid Rocket Booster cabling exposed in the VAB (Vehicle Assembly Building)

  • $\begingroup$ This is close to a link only answer. Please explain the links. @GandalfDDl $\endgroup$ Mar 21, 2023 at 0:06
  • $\begingroup$ This is good info, but does not answer "what is it for" - the new cabling, that is. To get the checkmark, that specific info is required in the answer. $\endgroup$ Mar 21, 2023 at 1:27
  • $\begingroup$ OK, clarified. Basically all the sensors / commands would need to transit up to the forward skirt where the main aviounics packages are now located for the SRBs. $\endgroup$
    – GandalfDDI
    Mar 21, 2023 at 4:44

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