Saturn V Direction Problem

[Hans Tucker]

Interesting info of the Engineering behind the Saturn V

https://youtu.be/KswUfPnTwvQ?si=uuh_Q3Yb0aDy1xvv

[gary]

Hi Hans,

You might be interested in my June 2019 posting here on IceInSpace entitled :-

'"Guidance is internal". The remarkable Saturn V ST-124 inertial platform' (https://www.iceinspace.com.au/forum/showthread.php?t=176004)

that also includes photos and a link to a pdf :-

"A GENERAL DESCRIPTION OF THE ST124-M INERTIAL PLATFORM SYSTEM" (https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650024833.pdf)
by Herman E, Thomason, George C. Marshall space Flight Center. Huntsville, Alabama, NASA document, Sept 1965

See https://www.iceinspace.com.au/forum/showthread.php?t=176004

[By.Jove]

Buzz Aldrins PhD thesis is also a fascinating read for the mathematically inclined.

[LonelySpoon]

I'm always amazed that the entire Saturn V was designed using paper and slide rules.

Some of you might need to Google "Slide Rule"...

Cheers,

Neville
LSO

(BTW, my Lego Saturn V was designed entirely by computer... weird)

[Leo.G]

I have a near new slide rule here. I'm stuffed if I can remember how to use it.
Gone are the days of slide rules and Log tables.
I do love my still working calculator though, an old Casio FX790P with full programming functionality (Basic or machine code) required in the 80s for the electronics engineering studies. Along with a course in basic so we could use the things.


Saturn V
I have 4 original slides here of the Apollo 14 launch (published in the ASNSW monthly thing at one time). An old online friend of many years (Also a doctor (chemical engineering)) assisted a NASA doctor who took launch photos from a special staging area. He was gifted a set of 4 genuine, non published slides for his help and one of Apollo 13 going through the atmosphere (across the sky). My then 94 year old friend found the slides and the original letter gifting the slides and rights of these slides to him during a move from Florida and gifted them to me in Aus. The reproduced photos hang proudly on my living room wall.

Sadly I've lost contact with this friend after his wife of many years passed away Christmas eve 22 and he expressed his sorrow and loneliness. I think/hope his family may have moved him into a home.

[bojan]

Slide rule was a fantastic extension (or addition) to logarithmic tables.. I was using both during my studies (tables at high school, slide rule (Faber-Castell Darmstadt electro) at uni. The first exam I had on year one (uni) was slide rule calculations).
At some point, I was able to "use" slide rule in my mind (I think I had photographic memory.. not any more, unfortunately), the accuracy was ~10% or better (for up to 2-3 multiplications/divisions).
The most practical slide rule I had was round one (still can be found on ebay (https://www.ebay.com.au/itm/275817490981?chn=ps&_ul=AU&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&mkscid=101&itemid=275817490981&targetid=1278430613456&device=c&mktype=pla&googleloc=9071333&poi=&campaignid=19649531412&mkgroupid=146789074798&rlsatarget=pla-1278430613456&abcId=9305371&merchantid=7364522&gad_source=1&gclid=EAIaIQobChMIoaPP_pqRhQMVvQ2DA x1n1A1yEAQYBCABEgJOUfD_BwE), made in USSR back in late '60-ties.. It could be used with single hand, and conveniently stored in pocket :-)
And yes, I am sure I would know how to use it today, provided I had one :P

[Leo.G]

I think my old slide rule comes with instructions, I'll have to look for it. As for log tables I had the capacity to memorise them when I was younger, made my studies much easier. Now I don't remember what I had for breakfast and I eat the same thing every day.

[gary]

My brother-in-law was gifted a 6"x4" American cloth flag hand-signed
on the front along with accompanying letter written and signed by
Edgar D. Mitchell stating that it flew aboard Apollo 14 with he and Alan
Shepard in the Lunar Module Antares and down to the lunar surface.
Plus we know its provenance.

It's identical to the one pictured here.

[Leo.G]

That's quite the memento Gary.

[gary]

Though slide rules were used extensively for myriads of tasks
in the design of the Saturn, it is somewhat of a whimsical notion that
they were used exclusively. :)

Pretty powerful mainframe and mini computers were also used at the
time, including the Honeywell 1800 (1964), the IBM 7090 and
various models of the fabulous IBM 360 (introduced 1965).

So before the Saturn V was even built, IBM 7090's were
used to perform the initial calculations to determine thrust and trajectory
of the vehicle.

Software like LUMINARY which was the name of the program for the
Apollo Guidance Computer (AGC) installed in the Lunar Module (LM) were
originally coded and simulated on Honeywell 1800 and IBM 360/75 mainframes.

A model 360/75 was a pretty powerful machine. 32-bit with the famed
general purpose 360 instruction set and had about a MIPs performance.
(The number 360 came from the fact the computer was all-encompassing
for both scientific and business calculations - 360 degrees - and a
compass motif appeared in the logo). The 360 had in-built floating point
support, parallel arithmetic, interleaved memory, 256K of core memory.
All in all pretty capable.

IBM was a prime contractor on the Saturn V. The Saturn V
Instrumentation Unit or "IU" was a ring that stood atop the third stage
and along its interior walls were the Saturn V guidance computers.
It was no coincidence that many of the components within these
computers were borrowed from the IBM 360 circuitry.

There were also good mini computers available at the time like the
Dec PDP-8 series.

But in the 1960's, a lot of people just commonly used electo-mechanical
desktop calculators like the Marchants and the luckier, including NASA
during the Apollo program, used the Olivetti Programma 101. These
were similar to calculators today in they supported add, subtract,
multiply and divide and could do square roots. Plus they were programmable!

I remember playing with these type of calculators in the 1960's where
my father worked. Often an Olivetti was brought back to our home
after work. It was always fun to give them a long division and
watch them chug away. But they were pretty amazing.

See "The Calculator that Helped Land Men on the Moon" at the
The Institute of Electrical and Electronics Engineers web site here :-
https://spectrum.ieee.org/the-calculator-that-helped-land-men-on-the-moon

Wikipedia on the Olivetti Programma 101 desktop calculator
https://en.wikipedia.org/wiki/Programma_101

Video of one in operation :-
https://www.youtube.com/watch?v=fcaNhfOKjIE

Promotional video :-
https://www.youtube.com/watch?v=WnItIQSwfSw

Pictures of Honeywell 1800 and IBM 360/75 installations below,
a Marchant calculator and an Olivetti Programma 101 desktop
calculator

[AstroViking]

Adding to Gary's post there is the book "Digital Apollo" that details the design and evolution of the computer systems that controlled / guided the landing module.

Well worth a read!

[gary]

I have a copy of it and it is a good read, particularly how it describes
the man-computer-machine loop with the LM firmware in particular being
an early embodiment of a computer controlled fly-by-wire system.