NASA HP-41 Flight Procedures Handbook

[Gene Dorr]

In my quest to learn more about the HP-65s that were carried on the ASTP flight, I ran across the "HP-41 Flight Procedures Handbook" for STS (Shuttle). I noticed that this has been mentioned in various threads here over the decades, but never actually surfaced ... so here it is, available (for now) to download from my "HP-65 in Space" page.

[Didier Lachieze]

Thanks for sharing this document. Another step to a comprehensive archive of the HP-41 usage on the Space Shuttle.

[trojdor]

That's really cool info....thanks for making that available.

I didn't realize they used the 41 for 9+ programs.

I was aware of the CG program, the Comms pgm, and the de-orbit calculations.
But I was totally unaware of the rest.

I was so lucky to be born at a time, when I got to watch the first US astronauts go into space with Mercury, the first American space walk with White/Gemini, the first moon landing with Apollo, watching while holding our breath for Apollo XIII, the Shuttle, the ISS, and now the privatization of space flight.

I was also lucky enough to spend several hours with James Irwin of Apollo XV, and listen to his stories.

Several of my engineering teachers came from the space program, after the mass NASA layoffs at the end of the Apollo program, and it was always great to hear their stories and insights, as well.

It was an optimistic time, when we believed anything was possible, and we knew something new and exciting was always just around the corner.

And we were all in it together....on our tiny little planet.

mike

[Steve Simpkin]

Thank you for posting this Gene and very well said trojdor.

Earthrise, taken on December 24, 1968, by Apollo 8 astronaut William Anders.

https://en.m.wikipedia.org/wiki/Earthrise

[twdeckard]

Are the actual hp41 routines documented anywhere?

[amalahama]

(04-29-2022 12:58 AM)twdeckard Wrote:  Are the actual hp41 routines documented anywhere?

I've been following this topic too. As far as I know, the actual programs are still missing but after this document I have the feeling we are a step closer to eventually find them out.

Also, during the nineties they started using the HP48G in their flights. I know they were using already laptops but there are some pictures in space with a -48G in their hands. I have found zero info about the ad-hoc programs developed for the 48G though, it's even less documented than the -41 usage.

Best regards

[Massimo Gnerucci]

(04-29-2022 07:40 AM)amalahama Wrote:  [Also, during the nineties they started using the HP48G in their flights. I know they were using already laptops but there are some pictures in space with a -48G in their hands. I have found zero info about the ad-hoc programs developed for the 48G though, it's even less documented than the -41 usage.

Ancient debates about this theme.

Another one.

[Ángel Martin]

(04-29-2022 07:40 AM)amalahama Wrote:  

(04-29-2022 12:58 AM)twdeckard Wrote:  Are the actual hp41 routines documented anywhere?

I've been following this topic too. As far as I know, the actual programs are still missing but after this document I have the feeling we are a step closer to eventually find them out.

The only Shuttle-related routine I'm aware of is the published in the Professional Computing V1N4 1984 magazine article, which Jürgen Keller published on his Calculator Nostalgia web site.

[Jlouis]

Excellent thread.

Where is the like button?

[rexbinary]

Thank you for posting about this.

[Tom Flatterhand]

That's really cool! Proof that the HP-41C really did have a role in shuttle flights! Thanks!

[Maximilian Hohmann]

Hello!

(05-01-2022 04:52 PM)Tom Flatterhand Wrote:  Proof that the HP-41C really did have a role in shuttle flights! Thanks!

We don't really know if it had a role other than being carried on board... I looked through the manual and most of the functions are provided for emergency use or in cases with total loss of communication with the ground stations. Neither of them occurred during the Shuttle operations (apart from the two accidents) and in the latter case, the loss of communications, the "infinitely" more powerful onboard computer would still have worked.

Out of curiosity I looked at the "landing program". Most of what it does (compute things like speeds for approach and landing or landing roll distances) is done with an iPad these days in the operation where I fly. So I guess the HP-41 could have been of some use there in case of a loss of communication and the loss of the onboard computer. This only covers the final approach phase though. The difficult part of landing a Shuttle is not this phase, but how to maneuver it into a postion from which the final gliding approach can be performed following the de-orbit burn.

Regards
Max

[Tom Flatterhand]

But they seem to have given serious thought to how to provide an alternative in the event of failure of the normal navigation facilities (the board computers). They probably had a meeting to think about what calculations they would need minimally and had someone develop the programs needed to do that. After all, that all costs time and money. For me reason enough to assume that it plays a role. :-)

[jonmoore]

Whether the 41 was actually used or not isn't the pertinent point here. The fact NASA felt the 41 could be used as part of a backup plan (and created a portfolio of suitable programs) is reason enough to prove that those classic HP calculator ads were more than clever marketing on HP's part.

BTW, that HP in space blog is probably my favourite HP related blog from over the years. It's something I return to time and time again - so many tasty nuggets of calculator lore to be found amongst its posts.

[Jurgen Keller]

(04-29-2022 09:33 AM)Ángel Martin Wrote:  

(04-29-2022 07:40 AM)amalahama Wrote:  I've been following this topic too. As far as I know, the actual programs are still missing but after this document I have the feeling we are a step closer to eventually find them out.

The only Shuttle-related routine I'm aware of is the published in the Professional Computing V1N4 1984 magazine article, which Jürgen Keller published on his Calculator Nostalgia web site.

For our English speaking friends: ignore the German text at the beginning and look at the link at the bottom of the page to grab the article (in English) as PDF document. Enjoy!

[Amy Collins]

(04-28-2022 08:12 PM)Gene Dorr Wrote:  In my quest to learn more about the HP-65s that were carried on the ASTP flight, I ran across the "HP-41 Flight Procedures Handbook" for STS (Shuttle). I noticed that this has been mentioned in various threads here over the decades, but never actually surfaced ... so here it is, available (for now) to download from my "HP-65 in Space" page.

Thank you, Gene!
To help solve the debates about the HP-41CV in space, I can accurately make a statement that that multiple HP-41CV's were flown on every Space Shuttle Mission STS-1 (April 1981) through STS-44 (November 1991) inclusive and including the controlled mode DoD missions, and that the latest observed in-cabin usage of HP-41CV's was by Vance Brand on STS-35 (December 1990).

I think the confusion about which programs were loaded onto each HP-41 is a result of SPOC (SPace Operations Computer) or GRiD Compass "inheriting" certain duties as the generations of these machines were upgraded. The HP-41 programs were reduced to carrying only those that were flight critical backups. (Deorbit, Cabin Leak, CG)

The full mainfest of calculators and laptops such as SPOC can be found in each mission's "Flight Data File Reference Data Flight Suppliment" JSC-48042-X as well as the logic/keypress charts as seen in the document you found.

The HP-48's were flown from STS-42 (January 1992) onward until at least the time of the STS-107 Columbia accident in 2003. During the program recovery time the Thinkpad A31p PGSC's were introduced, and calculators were no longer listed in the manifest.

More to come...

[Ángel Martin]

(10-12-2022 05:11 PM)Amy Collins Wrote:  More to come...

Thank you for an authoritative contribution to this subject; it rekindles my hopes to finally unearth the *actual* programs used in the flights.

Cheers,
ÁM

[aurelio]

There is an interesting discussion about Thinkpad PGSC's on the nasaspaceflight.com forum...

Thank you Gene, for the PDF document

[Gene Dorr]

Amy-

I'm very interested in your "More to come" teaser!

Ángel-

I'm curious about your desire "to finally unearth the *actual* programs used in the flights" -- why does that matter to you? I ask because I'm trying to formulate an argument that I can present to the NASM curators who are responsible for the ASTP-flown HP-65, to convince them to let me read the program cards in their collection -- and am finding it challenging to craft a truly compelling argument -- beyond "I'd really, really like to see them."

Gene

[twdeckard]

I am also very interested in the "actual" software. Nothing would please me more than to take my carry-around 41 and configure it, overlays and all, as if it was ready for flight.

If I could offer some rationale ... as we move into this exciting new future of privatized space - capturing the precise history of the role NASA played and will play in this transition is imperative (and only the future will know why).

Something will be lost if we do not bridge from the evaporating physical archives of the 70s into this distributed shared persistence of the world internet and they have an opportunity with enthusiasts like you to digitize and preserve even to the small corners free of charge.

If there is any practical value perhaps some young enthusiast in the future trying to pack as much capability into some nano satellite will take inspiration from the kepler loop in a 600khz processor as they build some organic quantum program out of crispr fabricated e-coli. Perhaps just posting those actual programs next to the picture of Dr. Ride floating with her calculators will spark the realization that mortal people made space grade applications and steer some brilliant young person into STEM

Who knows. Its more the sentiment that storage is free and we should be frantically digitizing everything.

Good luck!