This was the coldest launch before 51L, and yes it was 53F at launch. This was still too cold for the o-rings. Bear in mind that the worse O-ring damage they had ever seen before 51C and 51L was on STS-2 and the temp at launch that day was over 80F. So temperature was an additional stress on the already faluty joint design.
The change to the extra light weight SRB casings was also and issue. less weight means thiner walls on the segments = even more "balloning" at SRB start.
Yep this was the flight that was the main concern for the Thiokol engs before 51L. Chances are if there wind shear aloft had been as bad as it was for 51L, this flight would have been lost. The only thing keeping the seal on the joint was propel lent combustion products and glassy soot. Same thing happened on 51L but that flight had the most severe wind shear of any STS mission, and the guidance system had to do a lot of nozzle steering. The stress caused the soot seal to fail.
Yeah it was cold--and this was almost a year before 51L Challenger accident--this one here 51C was Jan. 24, 1985--and because of the cold temps here the hot exhaust burned past the first of the 2 O-Rings and was held back by the 1 O-ring. Roger Boisjoly-the engineer who tried to sound the alarm about cold temps and o-rings and tried to stop Challenger the night before--he said when they got the boosters back from this flight here-51C-he said he 'damn near had cardiac arrest'.
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Andrewmcmelonse 2 years ago
January 24 1985. sts 51c.
January 28 1986 sts 51l.
CCPerry09 2 years ago
This was the coldest launch before 51L, and yes it was 53F at launch. This was still too cold for the o-rings. Bear in mind that the worse O-ring damage they had ever seen before 51C and 51L was on STS-2 and the temp at launch that day was over 80F. So temperature was an additional stress on the already faluty joint design.
The change to the extra light weight SRB casings was also and issue. less weight means thiner walls on the segments = even more "balloning" at SRB start.
Zoomer30 2 years ago
Yep this was the flight that was the main concern for the Thiokol engs before 51L. Chances are if there wind shear aloft had been as bad as it was for 51L, this flight would have been lost. The only thing keeping the seal on the joint was propel lent combustion products and glassy soot. Same thing happened on 51L but that flight had the most severe wind shear of any STS mission, and the guidance system had to do a lot of nozzle steering. The stress caused the soot seal to fail.
Zoomer30 2 years ago
So damn near was destroyed, they were very lucky. And It would have been the first time an Apollo Astronaut died on flight.
EndeavourLaunch 3 years ago
right now here at orlando the tempeture is 45 degrees
shuttleluis 4 years ago
Yeah it was cold--and this was almost a year before 51L Challenger accident--this one here 51C was Jan. 24, 1985--and because of the cold temps here the hot exhaust burned past the first of the 2 O-Rings and was held back by the 1 O-ring. Roger Boisjoly-the engineer who tried to sound the alarm about cold temps and o-rings and tried to stop Challenger the night before--he said when they got the boosters back from this flight here-51C-he said he 'damn near had cardiac arrest'.
BigBill783 4 years ago 5
And El Onizuka was on that flight.
AndrewTiffin 3 years ago
I Heard that launch day for STS 51-C was 53degrees.
MrBennetzen 4 years ago
now they added a 3rd O ring and added heaters to them
Andrewmcmelonse 2 years ago