[amsat-bb] Re: Apollo 12

Rick Tejera saguaroastro at cox.net
Mon Nov 14 16:03:42 PST 2011


I'll have to listen again.. and yes they reset it before TLI. They were
quite busy during the parking orbit. Dick Gordon had to realign and reset
the guidance platform, no easy task considering he had no reference as he
normally would have. Also he had trouble identifying the Alignment Stars as
there was a lot of debris from the jettison of the Optics cover and the
alignment stars were in the southern part of the sky, and were not the
brightest stars n the catalogue. While he was at that Conrad and bean had to
bring the fuel cells back on line and get all the electrics & systems up &
running. Conrad was concerned that the forward RCS thrusters may have gotten
water in from the rain and possibly frozen (Which fortunately was not the
case. All this and the usual pre TLI tasks.

As for Apollo 11, most folks think the words spoken on the moon were
"Houston Tranquility base here, the Eagle has Landed" Not so. They were
Aldrin: "ACA out of detent" Armstrong: "Out of detent Auto", Aldrin: Mode
Control, Both Auto, Descent engine command override, off.  Engine Arm off,
413 is in".

The ACA was the Attitude Control Assembly which turned the RCS thrusters
off. If they didn't so this the thrusters would have continued to fire
trying to maintain attitude. The remaining items essentially safed the
descent engine and 413 in was a command to the AGS (Abort Guidance System)
that told the System, they'd landed and to note this position for reference
n case of an immediate abort.

If you hadn't noticed, I'm fascinated with the Apollo missions. :)

I recommend the book: "How Apollo flew to the Moon" by W. David Woods for
those interested n learning more about the engineering & mechanics of the
moon missions. 

Clear Skies

Rick Tejera
Saguaro Astronomy Club
Phoenix, Arizona
saguaroastro at cox.net 
K7TEJ, AMSAT 38452

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Burns Fisher
Sent: Monday, November 14, 2011 15:18
To: amsat-bb at amsat.org
Subject: [amsat-bb] Apollo 12

> >> ... Remember Apollo 12?
> ------------------------------
> Message: 8
> Date: Sun, 13 Nov 2011 22:03:01 -0700
> From: Rick Tejera <saguaroastro at cox.net>
> To: Clint Bradford <clintbradford at mac.com>
> Cc: AMSAT BB <amsat-bb at amsat.org>
> Subject: [amsat-bb] Re: Would NASA Ever Launch in this Weather?
> Message-ID: <144F3CBB-6919-421B-8FDA-45F230C17E48 at cox.net>
> Content-Type: text/plain;       charset=us-ascii
> And mission saved because EECOM controller remembered a test that had the
> same garbled pattern on his screen. He told the crew (through the Capcom)
> to "Try SCE to Aux". The NY other person who knew what he meant was LMP
> Alan Bean. Fortunately the switch was by his head. He flipped it and
> telemetry was restored.
> Among flight controllers the term SCE to Aux is considered legendary.
> Btw, SCE stands go Signal Conditioning Equipment. The SCE converts raw
> signals from instrumentation to standard voltages for the spacecraft
> instrument displays and telemetry encoders.
> Sent from my iPod
> Rick Tejera
> Editor, SACnews
> Saguaro Astronomy Club
> www.saguaroastro.org
> On Nov 13, 2011, at 21:51, Clint Bradford <clintbradford at mac.com> wrote:
> > Touche, Rick. Two lightning strikes ... ABORT handle grasped for minutes
> ...
> >
> > http://youtu.be/ajOsHVK11Lw
> >
> > Clint
> >
> >>> ... Remember Apollo 12?
> >
Check out this transcript.  Notice that PA makes no mention whatever of the
problem?  I remember (and actually heard in real time) the "Program Alarm
1201" calls (and was worried before Walter and Wally noticed, as I recall)
on Apollo 11, but I don't remember the SCE to Aux call at all.  They must
have switched it back before TLI, right?  Surely they would not head off to
the moon with no backup...

Burns, W2BFJ
(who also knew they had landed before Walter..."Contact light...engines
stop."  Wait several seconds, they are still talking.  They must have

Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

More information about the AMSAT-BB mailing list