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Author
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Topic: Photo of the week 959 (March 11, 2023)
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heng44
Member Posts: 3657
From: Netherlands
Registered: Nov 2001
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posted 03-11-2023 03:30 AM
   
 Replacements for the cracked fins of the Saturn 1B launch vehicle for the Apollo-Soyuz mission are being installed in the Vehicle Assembly Building at Kennedy Space Center on March 11, 1975. |
LM-12
Member Posts: 3751
From: Ontario, Canada
Registered: Oct 2010
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posted 03-11-2023 05:26 AM
The ASTP spacecraft was stacked on March 19, so that must be a dummy spacecraft seen on the launch vehicle in the photo. |
NavyPilot
Member Posts: 90
From: USA
Registered: Nov 2015
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posted 03-11-2023 12:26 PM
My notes say that they used BP-30 at some point on ASTP. |
LM-12
Member Posts: 3751
From: Ontario, Canada
Registered: Oct 2010
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posted 03-11-2023 08:57 PM
I have read that all eight of the first stage tail fins were replaced. Here is a photo of the SA-210 vehicle (and the ASTP crew) at Pad 39B. It looks to me like two of the new fins (III and IIII) ended up in the "wrong" location. I guess it launched that way. Weren't the four numbered fins (I, II, III and IIII) normally 90 degrees apart? |
LM-12
Member Posts: 3751
From: Ontario, Canada
Registered: Oct 2010
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posted 03-12-2023 11:17 AM
Here is a view of the SA-210 first stage for ASTP in January 1975, before the fins were replaced. Note the positions of the numbered fins. |
LM-12
Member Posts: 3751
From: Ontario, Canada
Registered: Oct 2010
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posted 03-13-2023 05:38 AM
Fittings (seen in the above photo) under the eight tail fins supported the weight of the launch vehicle and rested on the hold-down arms of the milkstool. So how were the cracked fins removed and replaced?A New York Times article about the Skylab 4 fin replacements mentions that the rocket was raised a few inches to take the weight off the tail fins. How was THAT done? |
LM-12
Member Posts: 3751
From: Ontario, Canada
Registered: Oct 2010
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posted 03-16-2023 04:46 AM
Those are actually position numbers and not fin numbers in the January photo: - fin 1 is position I
- fin 3 is position II
- fin 5 is position III
- fin 7 is position IIII
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LM-12
Member Posts: 3751
From: Ontario, Canada
Registered: Oct 2010
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posted 03-17-2023 09:27 PM
This Skylab 4 crew photo at the pad is dated November 8, 1973. That is the day they started replacing the tail fins on SA-208 seen in the background. The LUT crane might be positioned in the photo to assist in the fin replacements. 
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heng44
Member Posts: 3657
From: Netherlands
Registered: Nov 2001
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posted 03-18-2023 06:15 AM
I think this photo shows that the fins were well above the hold down posts and there was enough room to replace them. |
LM-12
Member Posts: 3751
From: Ontario, Canada
Registered: Oct 2010
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posted 03-18-2023 12:10 PM
I believe that is a Skylab 4 photo of SA-208 that shows fin 4 being removed, and (based on another photo) replaced with a new "III" fin. The other photo also shows fin 5 with a "III" fin. As I understand it, the fittings (hidden in your photo) under the fins were mere inches above the hold down posts when the fins were removed and replaced. |
LM-12
Member Posts: 3751
From: Ontario, Canada
Registered: Oct 2010
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posted 03-18-2023 08:48 PM
Here is the photo I was referring to in the above post. Note the fitting at the #3 hold down post at left. |
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