Sunday, November 15, 2009

"Try SCE to Aux" - Apollo 12 + 40 years

Another 40th anniversary. This time it's the launch of Apollo 12, November 14, 1969. Pete Conrad, Dick Gordon, and Alan Bean were the 2nd flight to the moon after Apollo 11. Launching into a thunderstorm, the Saturn V was hit by lightning twice. "I got three fuel cell lights, an AC bus light, a fuel cell disconnect, AC bus overload 1 and 2, Main Bus A and B out!" was the call to Mission Control from Pete Conrad - who sat there with his hand on the abort handle.
The Saturn was still flying, so rather than yank the handle, they got a call from John Aaron, who had an idea "Try SCE to Aux" was his call. Alan Bean knew where that switch was, and flipped it to Aux. Telemetry was restored and Apollo 12 continued to the moon.

12 comments:

TonyNY77 said...

Just superb. I wanted to thank this blogger for having this Apollo 12 launch audio available. John Aaron's call to set S.C.E. to Aux is always portrayed as being somewhat miraculous ... and I tend to agree.

Thanks very much for making this audio available for everyone to enjoy.

Tom said...

I forget where I found that audio, but liked it so I posted it as a blog entry. I keep thinking of some kind of space geek license plate for my truck and kind of debate between "SCE2AUX" or "GO4TLI". (very few would get those!)

TonyNY77 said...

Tom ... Excellent ideas, but I think I favor "SCE2AUX". I'm trying to think of something else, but nothing comes to mind that would fit on a license plate. You made a great choice.

As a couple of side comments related to our manned space programs, I just wanted to add:

(1) I very much dislike the term "blast off." As I recall, earlier during the U.S. space program when there were more launch failures, NASA public relations people used to get pretty bent out of shape if any members of the media referred to "lift off" as "blast off." I'm old-fashioned, therefore I don't care for "blast off" either. Nowadays, though, no one seems to mind "blast off." I still notice, though.

(2) I guess launch procedures may have changed. In the "old days," launch preparations were controlled by Kennedy Space Center until the "tower clear" call. Now, though, I believe Houston takes control at the moment of lift off. Again, I'm quite old-fashioned and I very much enjoy hearing that "tower clear" call. Since hearing an astronaut interview where booster/launch technology was compared to balancing a pencil, I suspect some of the old-timers may still appreciate hearing that call. In one interview, an astronaut mentioned all the gimballing that's occurring early in the launch, and the astronaut expressed concern that a sudden high wind gust might cause a cataclysmic launch failure. Under such a high-wind-gust condition, I suppose that the engine gimballing would be sufficient to maintain proper vehicle attitude/orientation, but there would be no assurance that the gimballing wouldn't lead the vehicle right into the launch tower. I don't think we've seen that kind of failure. Have we? Yes, some pads/tower assemblies were destroyed in the early days, but did any of these failures occur because the vehicle gimballed itself into the tower? I don't know for sure.

(3) Another thing that often disappoints me: I realize that some launches had engine start scheduled to occur at T-Zero. However, I often see historical footage or launch re-enactments where the presentation is incorrectly edited/narrated. Many such re-enactments show engine start at T-Zero even when lift-off actually occurred at that moment. Sorry to be so picky, but that's another one of those little things that disappoints me.

(4) Lastly . . . How about Apollo 11's lunar landing? How many times have we seen/heard the landing re-enacted this way: "Okay, engine stop. Houston ... Tranquility Base here. The Eagle has landed." What happened to the engine safing procedures? These incomplete re-enactments make the landing seem as simple as turning a car's ignition switch to the off position." Baloney!

Well, I guess I've said about enough, but I was feeling a bit motivated. Thanks, Tom. Have a good one and all the best with your blog!

Tony

Tom said...

Great comments Tony, I agree!
I haven't bought a new license plate yet, but still thinking of dong that.

1) Yes, I do hate when they say "blast off", and I have heard that NASA cringes when that is used also. It's more of a "Buck Rogers" Sci-fi kind of think, like "A-OK" also. Ha!
(I can add "Tang" also)

2) As for the tower clear thing, I wonder if the speed of the shuttle just doesn't give them time for that? The shuttle doesn't mess around, it's up and going once the SRBs ignite. The good old Saturn V (still my favorite) sat there and kind of slowly picked up speed while wobbling back and forth on the gimbaling F-1s. Seemed they had more time to worry, watch and then finally say "tower clear". Just some thoughts on that which come to mind as I type this.

3) Again, I agree! Ignition starts before T-0. Saturn took a while to "spool up" those 5 monsters before cutting it lose. The shuttle has to test out it's engines for a few seconds so the computers realize they are good to go, wait for the twang, and then commit by firing the SRBs.

4) Yeah, there was a few things to do after landing to secure the spacecraft or get ready to launch again immediately if needed. All that stuff is cut out too. I'm hardcore and like to hear it all. I did a search and stumbled on this poster again that I saw last year during the 40th anniversary - http://tinyurl.com/2aofm4n
Fun!

Thanks for the comment, always refreshing to find someone out there that "gets it" also if you know what I mean.

-Tom

TonyNY77 said...

Hi again, Tom. I hope you and all the Astro bloggers are doing okay.

I simply wanted to mention two space program titles I recently received/viewed via my Netflix subscription: "In the Shadow of the Moon" and also "Magnificent Desolation."

Both were excellent, I thought, but I slightly preferred "Magnificent Desolation." There was only one prominent disappointment. I'll explain this.

As the launch of Apollo 11 was re-enacted, as you might imagine, the terminal phase of the count was replayed slowly from several perspectives to stress the many things that are occurring prior to and after lift-off. They had a view looking up into the nozzles of the first stage's F-1 engines during engine start; they showed ice falling from the vehicle's outer skin, the hold-down arms releasing, and views of the swing arms/umbilicals retracting at lift-off, etc.

Here's the disappointment: Despite playing Jack King's (the "Voice of Apollo") announcements, the re-enactments showed engine start at T-Zero. For all the trouble they went to in order to produce an excellent, high-quality, accurately re-enacted production, something as important as lift-off should have been properly presented, I feel.

But that's just me, perhaps. Other than that, these two presentations were excellent and I highly recommend both of them.

All the best to you, Tom, and to the fellow bloggers.

Tony M.

Tom said...

I do have both of those documentaries. I bought them as soon as they came out.
I like them both, they are both very different, I like the interviews in "Magnificent Desolation" but then the footage in "Shadow of the moon" was excellent. There was actually footage that even I haven't seen before! I remember seeing that in the theater when it came out, I was so excited afterwards that I nearly had coffee come out my nose when we stopped at Starbucks after the movie. :-)
I'll have to watch it again to see the T-0 thing. I think the public would just get confused about that, so maybe that is why they skew the audio and video?
Have you seen this one?
http://vimeo.com/4366695

Tom

Tony More said...

Well, Tom ... I guess it's already too late to "hate" you for all the good and interesting things you've made me aware of. Thanks to you, the new space program material you've introduced me to is keeping me from my chores and other things I ought to be doing. At this very moment, my wife is nagging me to come to bed. I'll just tell her it's your fault.

Seriously, though, the video you mentioned at Vimeo.Com was superb. Of course, I've seen the first few seconds of that footage over the years in countless news reels, etc. However, until now, I had never seen the entire film. Mark Gray's narration was absolutely excellent, of course. I have yet to explore what ever additional material of interest he might have there, but I'll be looking into it as my spare time permits. Good thing I'm retired.

Now I know what the tail service masts are. Not being as knowledgeable as other enthusiasts, I had been confusing the the tail service masts for the hold-down arms. I guess my eyes were always drawn to the equipment in that film that moved the most. Being that the tail service masts make the right kind of motion at the right time, I can't let myself feel too bad for not knowing better.

Not knowing what the tail service masts were, I searched and found a great link at a NASA Web page showing both the tail service masts and the hold-down arms: http://www.hq.nasa.gov/office/pao/History/SP-4204/ch13-4.html If you haven't seen it, I'm sure you'll get something from it.

Oh, how about another question regarding the SCE switch? In Scott Glenn's narration for one of the popular videos explaining John Aaron's role in saving Apollo 12, they say that the SCE switch actually had some other purpose. But John Aaron, the inquisitive man he is, happened to know about it and also knew it would work to solve the problem Apollo 12 endured from the lightning strike(s).

So, the question is, I wonder what the SCE switch was actually intended to do? I don't pose that as a challenge to anyone; I'm just wondering out loud what its real/primary purpose was.

And while you're at it, I wish someone had a way to explain something to me in terms a simple man like myself could understand: After all these years, I'm still wondering exactly what "gimbal lock" is. I realize it's got something to do with the spacecraft's alignment gyros ... And all of us know it's a condition they avoid with a passion. Other than that, I still don't know what it's all about. So if you happen to know and can tell me in a way I might understand, please pass that info along too.

Well, once again, I've hogged up a full screen of your blog, Tom. I hope you don't mind too much. But the way I see it, at this rate, maybe in about another ten years, I might be qualified to sit in a Mercury spacecraft simulator ... or maybe I'd fulfill the prerequisites for adult space camp.

As always, thanks again, Tom, for this great, great blog site. I, for one, greatly appreciate it.

Tony More said...

Just call me ignorant, Tom. Even though I also started a blog via Blogger.Com, I haven't had time to work with it much. Until now, I thought the page entitled "Try SCE to Aux ..." was the entire blog! However, I nosed around a bit and entered again via a different link. Wow!!! I was surprised, impressed, overwhelmed, and just plain floored.

I've subscribed, but I doubt I'll be able to keep up. In any event, take my previous complimentary comments and multiply them by a thousand or so. Thanks very much and keep up the great, great work!

Honda93 said...

SCE to Aux cleared up problems with telemetry. Apparently aux signal conditioning circuits were less sensitive to low voltage conditions. While it is evident that getting telemetry back on helped mission control determine what the next step was.. I have never heard what they next step WAS?

Tom said...

This has been a good blog entry, messages keep showing up!
As for what happened next after they got telemetry running again, I'm not sure. I think Pete Conrad giggled for a while, then was cleared to fire the engine again for TLI.
Ha!

Tom

Robert Nielsen said...

Giggled?? According to John Aaron (From the History Channel's "Failure is Not an Option" DVD), "Pete Conrad broke out in nervous laughter." Although, the audio does sound like Conrad is giggling. I liked when he said, "There were so many lights up there, I couldn't even READ 'em all!!"

Alex said...

around this anniversary of Apollo 12, I recently wrote about "SCE to Aux" at Motherboard, and I thought some folks would like it. there's some video in there too:

http://motherboard.vice.com/read/john-aaron-apollo-12-curiosity-luck-and-sce-to-aux