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T O P I C R E V I E WejectrWhat would happen if the 3 main engines fired up and then only 1 SRB ignited?I'm assuming the computers would sense this, shut down the mains and the SRB that ignited would just burn out on the pad.Anyone know for sure?[This message has been edited by ejectr (edited October 09, 2005).]katabaticMy understanding is that would be a non-survivable event, with loss of the vehicle and severe damage to the pad.Apollo-SoyuzOnce the signal is given to ignite the SRB's, they cannot be shut down. If only one ignites, I think the vehicle will begin to tumble due to imbalance of thrust and is not survivable. ------------------John MaccoVice PresidentSpace UnitShady Side, Md.[This message has been edited by Apollo-Soyuz (edited October 09, 2005).]mjanovec quote:Originally posted by ejectr:I'm assuming the computers would sense this, shut down the mains and the SRB that ignited would just burn out on the pad.If I remember correctly, the signal for the release of the hold down arms is sent at roughly the same time as the SRB ignition signal is sent. So there really is no opportunity to hold the vehical in place in the event only one SRB ignites. BenFortunately, the chance of an SRB not igniting when the command is sent is smaller than you can imagine. It has never happened on any SRB ever so far as I am aware. It's one of the disaster scenarios that is not even considered.When NASA describes the frangible bolts breaking away they usually phrase it as, "we are *so* certain about the SRBs igniting that we fire the bolts 1/1000 second before they light."sfurtawI could be wrong, but I thought that I heard at Space Camp (which was some time ago!) that there are four igniters at the top of each SRB, each one acting like a flame-thrower shooting a flame down the booster. Can anyone confirm this?------------------Scott FurtawIn Memoriam: The Astronaut/Cosmonaut Memorial Web Sitewww.astronautmemorial.netspacecraft filmsI heard a discussion of this scenario once. Generally, it isn't a survivable event, but the response to such an event is described as throwing all three SSMEs and the one functioning SRB to the limit of their gimbals to correct the trajectory and try and ride it out.Remember that with the loss of an SRB the accelleration off the pad would be slow... with the thrust not that much more than the weight of the vehicle. And dragging along a fully-loaded SRB would really be a strain.Somehow I remember John Young being in this discussion and he ended it by saying something to the effect of "It would be a sporty ride."At least that is my recollection.Mark[This message has been edited by spacecraft films (edited October 10, 2005).]DavidHSo could you go ahead and fire the exploding bolts to release the SRBs?If so, what happens?------------------ http://allthese worlds.hatbag.net/space.php "America's challenge of today has forged man's destiny of tomorrow." - Commander Eugene Cernan, Apollo 17 Mission, 11 December 1972OV-105I think if only one SRB did light, I would hate to the RSO on that day. CJCIf the starboard SRB fails to ignite then the vehicle will hit the launch tower as it lifts off. If the port SRB fails then the stack might stand a chance of clearing the tower but the strain imposed on the stack would ultimatly tear it apart.CJC
I'm assuming the computers would sense this, shut down the mains and the SRB that ignited would just burn out on the pad.
Anyone know for sure?
[This message has been edited by ejectr (edited October 09, 2005).]
------------------John MaccoVice PresidentSpace UnitShady Side, Md.
[This message has been edited by Apollo-Soyuz (edited October 09, 2005).]
quote:Originally posted by ejectr:I'm assuming the computers would sense this, shut down the mains and the SRB that ignited would just burn out on the pad.
If I remember correctly, the signal for the release of the hold down arms is sent at roughly the same time as the SRB ignition signal is sent. So there really is no opportunity to hold the vehical in place in the event only one SRB ignites.
When NASA describes the frangible bolts breaking away they usually phrase it as, "we are *so* certain about the SRBs igniting that we fire the bolts 1/1000 second before they light."
------------------Scott FurtawIn Memoriam: The Astronaut/Cosmonaut Memorial Web Sitewww.astronautmemorial.net
Remember that with the loss of an SRB the accelleration off the pad would be slow... with the thrust not that much more than the weight of the vehicle. And dragging along a fully-loaded SRB would really be a strain.
Somehow I remember John Young being in this discussion and he ended it by saying something to the effect of "It would be a sporty ride."
At least that is my recollection.
Mark
[This message has been edited by spacecraft films (edited October 10, 2005).]
------------------ http://allthese worlds.hatbag.net/space.php "America's challenge of today has forged man's destiny of tomorrow." - Commander Eugene Cernan, Apollo 17 Mission, 11 December 1972
CJC
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