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Videos of the Challenger shuttle explosion show both solid boosters speeding on after the main tank detonated. Were they eventually self-destructed by the ground control, or why not, and why not immediately? Where and how did they land?

Same solid boosters will be used on the SLS. Will it have another abort system for its solid boosters?

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  • $\begingroup$ The crew didn't die until they hit the water. Maybe it was to give them a greater chance of survival because the explosion wouldn't be near the crew? Or maybe because everyone was in shock. $\endgroup$ – LateralTerminal Mar 22 '18 at 17:18
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The shuttle stack broke up at ~73 seconds after launch of STS-51L. The Solid Rocket Boosters separated from the other elements and continued flying in a more or less stable manner (surprisingly). Air Force range safety personnel detonated the boosters at ~110 seconds after launch using the self-destruct system built into the boosters. (timeline reference)

I have not seen any writeups explaining the ~30 second delay to sending the destruct command. Range safety operated using preplanned procedures which included predicted impact of the vehicle on populated areas (see What rocket launch protocols (if any) are in place to prevent premature or late intentional self-destruct? for some details) It may be that the flight termination lines were not crossed until then, or possibly the procedures did not cover the case of two free-flying stable SRBs, requiring some human judgment.

Speculation on the time delay: This Google Maps image shows a shuttle launch trajectory - this is for an ISS flight, the 51-L trajectory would have been due east. Although the image is small, you can see that at 73 seconds the shuttle would have been well off the coast and traveling east at high speed (there were no significant trajectory anomalies prior to the stack breaking up). I doubt the limit lines were crossed in this case, and I would imagine the delay was due to human judgment upon having encountered a case never considered.

enter image description here

These pages from the 1982 Rockwell shuttle press manual show the SRB range safety system.

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The debris landed in the ocean. Much of it was later retrieved including the critical segment which showed the burn-through from the O-ring, which greatly aided in the accident investigation. This is a photo of some of the debris on the recovery ship.(photo source)

enter image description here

The SLS SRBs do contain a flight termination system. Per this the first two SLS flights will use the same system as STS, after which it will be replaced by a more modern system.

...the Flexible Confined Detonating Cord Assemblies (FCDCAs), which are currently used on the SLS booster Flight Termination System that terminates thrust and distributes booster propellant in the event of an anomaly. FCDCAs will also replace the heritage shuttle devices on the Separation System after the second SLS flight. FCDCAs are the industry standard and serve the same purpose as the heritage CDFAs and CDFMs which were unique to the Shuttle design. The new pyrotechnic devices are lighter and more cost effective than the heritage shuttle devices. Due to environmental exposure, the fuse encased in FCDCA can develop fatigue cracks. EBA&D conducted risk-reduction testing, and it was verified that no significant fatigue cracking was caused by the SLS mission environments, and the FCDCAs would function properly after exposure.

(Acronyms: Confined Detonating Fuse Manifolds (CDFMs) and Confined Detonating Fuse Assemblies (CDFAs)) EBA&D is a subcontractor.

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    $\begingroup$ It seems pretty unlikely that they could have made it that far. The red dot on the map shows the nominal SRB sep location; they only had ~50 seconds of burn time left after the break-up. $\endgroup$ – Organic Marble Mar 21 '18 at 19:32
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    $\begingroup$ I wonder if the delay wasn't caused by shock. The Challenger disaster would undoubtedly have thrown things into chaos, and it's not too unreasonable to see 30 seconds vanish as people struggle to figure out what they're seeing, recall their training, and act on it. $\endgroup$ – Nic Hartley Mar 21 '18 at 20:58
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    $\begingroup$ I wouldn't be a bit surprised. That's certainly the expression I see on the faces of the flight controllers in Houston in the pictures from that morning. $\endgroup$ – Organic Marble Mar 21 '18 at 21:14
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    $\begingroup$ @NicHartley Probably not chaos. But I wouldn't be surprised by a brief moment of everyone standing in silence. $\endgroup$ – jpmc26 Mar 21 '18 at 21:27
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    $\begingroup$ Total speculation but might they also have been interested in letting the SRBs get well away from any possible survivors before blowing them up? $\endgroup$ – David Richerby Mar 22 '18 at 14:33
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Just put that question into google, ended up on the Range Safety System section of the SSSRB Wikipedia article, which contains this section:

A range safety system (RSS) provides for destruction of a rocket or part of it with on-board explosives by remote command if the rocket is out of control, in order to limit the danger to people on the ground from crashing pieces, explosions, fire, poisonous substances, etc. The RSS was only activated once – during the Space Shuttle Challenger disaster (37 seconds after the breakup of the vehicle, when the SRBs were in uncontrolled flight).

[...]

The NSDs provide the spark to ignite the CDF, which in turn ignites the LSC for booster destruction.

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    $\begingroup$ You did explain the abreviation RSS, but what about NSD, CDF and LSC? $\endgroup$ – Uwe Mar 21 '18 at 11:25
  • $\begingroup$ I just copied the relevant portions of the wikipedia article, if you click on the link you can read the longer version $\endgroup$ – Hans Mar 21 '18 at 11:26
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    $\begingroup$ NSD = NASA Standard Detonator, CDF = Confined Detonating Fuse, LSC = Linear Shaped Charge $\endgroup$ – Tristan Mar 21 '18 at 14:30

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