Thrust Chamber Throat Security Closure Shaft

When I was processing my photos of the F-1 engine high-pressure ducts taken in September 2013, I noticed that a G4089 thrust chamber throat security closure was laying in the pile. I cursed myself for not noticing it when I was actually at MSFC, but I added it to my list of things to photograph if I was ever on MSFC again. Luckily, it was still there when I visited in September 2014, and I was able to take these photos.

My first experience with the throat closure shaft was actually at the Michoud Assembly Facility in 2005. I noticed that several of the F-1 engines had an odd "spike" in the center of their injectors. I emailed the Michoud historian in this regard. He replied that didn't know what they were but guessed that they were some sort of ground support equipment.

I attended the AIAA's "50 years of United States Exploration, America in Space: A Technical Symposium" in the newly-opened Davidson Center for Space Exploration in 2008. One of the panelists was Sonny Morea, the MSFC official who headed the F-1 program. I showed him a photo of the shaft in the Michoud F-1, but he didn't recognize it. Also in attendance was Alan Lawrie; I recognized his name from his Saturn V book and asked him. While he didn't know, he knew a Rocketdyne retiree who identified it and sent me an informational diagram, which formed the basis of the throat closure page linked above.

So, while it was just a mundane piece of GSE, I was still rather excited when I was finally able to hold one of these in my hands and take detailed photos of it.