Pyro Relays vs. Isolation Valves

It has been brought to my attention via email that the difference
between the two is still not clear, so let me explain again. Scott
has been talking about the "A & C" RCS valves that did not go to
"safe." He has blended two different events into one, and that is
responsible for the confusion.
The RCS is broken up into two power systems: A & B. Further, there
are 12 isolation valves: Helium 1 A-D, Helium 2 A-D, and Propellants
A-D. The safe lights to which he is referring are the A & B safe
lights-- the BUSES. The valves that did not go to safe are the
helium 2A and 2C valves. Two different events, two different
problems. Neither set of RCS pyro relays (A & B) were in the safe
condition. However, 10 of the 12 valves WERE open (or safe).
I'm in a hurry at the moment, but I hope this clarifies things for
those of you who are searching.
Thanks for bringing it to my attention.
LaDonna

"LaDonna Wyss" wrote in message
om...
It has been brought to my attention via email that the difference
between the two is still not clear, so let me explain again.

You don't know the difference between your "teammates" and the law
enforcement personnel you contacted about Apollo 1?

"Scott Hedrick" wrote in message . ..
"LaDonna Wyss" wrote in message
om...
It has been brought to my attention via email that the difference
between the two is still not clear, so let me explain again.

You don't know the difference between your "teammates" and the law
enforcement personnel you contacted about Apollo 1?

Polly want a cracker???

"LaDonna Wyss" wrote in message
m...
Polly want a cracker???

Her name is *Betty*. Geez, first you torture her over her husband's death,
then you can't even remember her name?

"LaDonna Wyss" wrote:

It has been brought to my attention via email that the difference
between the two is still not clear, so let me explain again. Scott
has been talking about the "A & C" RCS valves that did not go to
"safe." He has blended two different events into one, and that is
responsible for the confusion.

Could you show us where Scott posted this error? Without context, your post
seems to disparage someone for an unverified error.

The RCS is broken up into two power systems: A & B. Further, there
are 12 isolation valves: Helium 1 A-D, Helium 2 A-D, and Propellants
A-D.

You are blending facts, too. The truth is that there are 16 isolation
valves associated with the SM RCS. Each propellant tank can be isolated by
its own "iso" valve in case there is a leak or other issue such as a need
for maintenance. Since there are four RCS quads each having two propellant
tanks (one fuel, one oxidizer) on SC 12, that makes eight (8) propellant
tank isolation valves. So there are eight (8) helium isolation valves and
eight (8) propellant isolation valves for an overall total of sixteen (16)
SM RCS isolation valves. So how did you err? You went by MDC panel 12,
IIRC, which shows that the there are four propellant tank isolation valve
control *switches*, and that is true; however each of those four propellant
isolation valve switches controls both the fuel and oxidizer isolation
valves for a given quad. Thus you blended a control panel issue with an
actual physical configuration of the spacecraft hardware issue. No harm no
foul, just as long as we get it right in the end.

The safe lights to which he is referring are the A & B safe
lights-- the BUSES. The valves that did not go to safe are the
helium 2A and 2C valves. Two different events, two different
problems.

But if the crew got 12 gray bars, and two failed according to some IDR,
IIRC, then doesn't that tell you a whole heck of a lot? It tells me that
the measurements that came up correctly for the crew "12 gray bars" did not
originate with the hardware which had the problem. Put differently, your
own evidence once again strongly suggests that the SM RCS valves were in
fact simulated values. When you come up with a better explanation, please
let me know.

Neither set of RCS pyro relays (A & B) were in the safe
condition.

However, 10 of the 12 valves WERE open (or safe).

None of the SM RCS helium isolation valves would have been operated for more
than five seconds to the closed position (energized) if they were operated
at all due to concern for heat related issues associated with the coils.

I'm in a hurry at the moment, but I hope this clarifies things for
those of you who are searching.

Me too.

Thanks for bringing it to my attention.

No problem.

Daniel

Actually, Scott has said this on numerous occasions, but the most
glaring is in the audio interview on his website. I thought you folks
were so in love with that website???? Listen to the interview; it's no
different than what he's said in many other places--radio, etc.
OOPS--YOU goofed. :-) It's Panel 15, and yes, I was talking about the
12 controls that are on the MDC. Obviously, with 16 thrusters, there
are 16 valves, but there are only 12 switches and twelve potential grey
bars.
As for the "heat related issues associated with the coils"--APPLAUSE!
Apparently you've finally HEARD ME! That's what I've been saying.
That was the problem.
And no, I have not quoted an IDR with regard to those iso valves,
they're on one of the schematics--AGAIN, go to Scott's website. You
don't have to venture past the home page to see everything you need to
see on the above. Listen to the interview, and look at the posted
diagrams.
LaDonna

See the answer I just posted to Charleston. As for a source for the
counting of valves--I'm curious as to yours. Is the name in quotes
supposed to be an article, a book, a section of a book or manual? My
sources are the Apollo Operations Handbook and the voice transcript,
along with side-sources, but I believe Charleston is using the AOH.
LaDonna

wrote:

Actually, Scott has said this on numerous occasions, but the most
glaring is in the audio interview on his website. I thought you folks
were so in love with that website????

I have listened to those audiotapes exactly once and my opinion of Scott's
website is irrelevant. Why you would toss the word "love" in there in
reference to his website, I don't know. I have linked to it when
appropriate.

Listen to the interview; it's no
different than what he's said in many other places--radio, etc.

OOPS--YOU goofed. :-) It's Panel 15, and yes,

LaDonna, the term "IIRC" means: *If I Recall Correctly* but you snipped out
the context of "OOPS--YOU goofed".

Here it is again to clarify the context and difference between an off the
top of my head remark, and your statement which was represented de facto.

"So how did you err? You went by MDC panel 12,
***IIRC***, which shows that the there are four propellant tank isolation
valve
control *switches*, and that is true; however each of those four propellant
isolation valve switches controls both the fuel and oxidizer isolation
valves for a given quad. Thus you blended a control panel issue with an
actual physical configuration of the spacecraft hardware issue. No harm no
foul, just as long as we get it right in the end."

***emphasis added***

I was talking about the
12 controls that are on the MDC. Obviously, with 16 thrusters, there
are 16 valves, but there are only 12 switches and twelve potential grey
bars.

Yes I know that but people unfamiliar with the spacecraft likely could not
have known that because you did not say what you apparently mean't, hence my
correction. Why it is important is that for each propellant switch on panel
15, any of two separate iso valves can be the source of the problem and can
cause a failure indication. Isolating that failure is limited to a specific
quad and not to a specific propellant tank. It is okay but it is limiting.
There are always limits to what you can know about hardware when you have
weight concerns.

As for the "heat related issues associated with the coils"--APPLAUSE!

You have got to be kidding.

Below you clearly state that the helium tank isolation valves are energized
in order to open them. That is clearly and factually incorrect. The helium
iso valves are *energized* to *close* them as they only need to be closed
for maintenance and filling for the most part. I was quizzing you to see if
you really understood how they functioned. During the countdown and mission
these valves are open so that the system is pressurized and since that is
the most common position for them to be in, that position is controlled by
mechanical latching so that the valves do not require constant energy which
is limited in supply. Also leaks in the system can be readily found by
ground and/or flight controllers before commitment to launch occurs as the
Helium pressure values will decay if the system is pressurized and there is
a leak.

http://makeashorterlink.com/?D5C7428B8

Are the valves open when they are energized or closed when they are
energized?

The helium tanks were empty weren't they?

We have not talked much about telemetry yet, but this is an area in which
rk
has tried to engage you in discussion on more than one occasion.

There are operational limits on those valves in the dry state that must be
strictly followed.

Daniel

In order to open the valves must be energized. Once degaussed, they
will not open.
The He tanks were empty.
The telemetry, other than the brief little snippets NASA has provided,
is still classified.
LaDonna


Apparently you've finally HEARD ME! That's what I've been saying.

No it is not.

That was the problem.
And no, I have not quoted an IDR with regard to those iso valves,
they're on one of the schematics--AGAIN, go to Scott's website. You
don't have to venture past the home page to see everything you need to
see on the above. Listen to the interview, and look at the posted
diagrams.

No, I will listen to the report thanks.

Daniel

wrote in message
...

Obviously, with 16 thrusters, there
are 16 valves, but there are only 12 switches and twelve potential grey
bars.

I just caught this and it too is irrelevant. The Helium valves are
redundant. That is why there are eight. The SM RCS system is bipropellant
and that is why there are eight propellant tank iso valves. It has nothing
to do with the number of thrusters.

Daniel

This is EXACTLY WHY I lose patience with posting here!!!!! I spend ten
minutes typing an explanation, only to have it lost because of a ^$$#!!
server error! I'm going to try again, but I am out of patience.
(Frankly I don't even have my train of thought anymore.)
What I was TRYING to say is: people were asking where the information
came from on the iso valve vs. pyro relay issue. I told you where to
find it. If you don't care to, that's your business. He's also talked
about it on radio, but chances are you won't catch replays. However,
I've ALSO directed you to the schematic on the website; apparently
you're refusing to do that as well.
As for the heat issue: you are ASSUMING all systems were being
monitored. They were not. In fact, MOST were not. Read the Record
again--or perhaps you should wait for Volume I. There were very few
monitors that afternoon, mostly because the test was deemed
"non-hazardous."
As to the drawing you posted--it's a very nice mock-up of the CSM.
However, you leave the impression the sector door was open! It was
not. Only the access doors were open, not an entire panel (that looks
like Apollo 13 after the explosion!)
As for a post I saw somewhere (I don't recall where): MAYBE there
would have been flames going up the wiring to the simulators. Maybe
NOT. You folks act like fires only take one given, preset path.
Perhaps we need a firefighter in the mix? There are a lot of factors
involved in where a fire will travel once lit.
HOWEVER, there is more than one witness statement that talks about a
cable being on fire--remember, Daniel?
LaDonna