[HN Gopher] Space Shuttle teleprinter reverse engineering
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Space Shuttle teleprinter reverse engineering
Author : DAddYE
Score : 87 points
Date : 2024-03-20 06:45 UTC (16 hours ago)
(HTM) web link (twitter.com)
(TXT) w3m dump (twitter.com)
| generj wrote:
| I am fascinated they used 60 pounds and a large amount of space
| for this teleprinter. At 30K per pound of payload that is $1.8
| million per flight. Really shows how important reliable printed
| updates were considered.
|
| And all the flaws of the printer that were managed around -
| turning it off to save power and prevent it overheating with
| specific tones.
| eddieroger wrote:
| I was pretty stuck by that, too, and it made me wonder if maybe
| I don't understand or underestimate the value of paper
| transmission. I suppose if radio communication is good but
| flaky, or for persistence of instruction, like procedures, then
| it would be good for them to be able to print. But at such a
| cost!
| willcipriano wrote:
| At least communism was defeated.
| actionfromafar wrote:
| This is true, but in hindsight only a partial success. A
| good chunk of the _communists_ weren 't. :-/
| a_gnostic wrote:
| Communism is the very definition of failure.
|
| Return, refit, and redeploy to purge the stain of this
| failure with the peroxide of victory!
| krisoft wrote:
| I guess with modern googles one would just pack an "ipad"
| equivalent tablet. If one worries about accidents and freak
| space particles disabling it give them 3. If one still
| worries one can develop a "space rated" tablet. But probably
| at those radiation levels one should also start worrying
| about the crew's health.
|
| But of course that is projecting our current capabilities
| back in time. I looked it up and the "Osborne 1" portable
| computer[1] was just released 9 days before the shuttle's
| first flight. It weighed 24.5 lb (11.1 kg) and could display
| 52 x 24 characters on a small CRT. So yeah, that would not be
| nice to read manuals with :D
|
| 1: https://en.wikipedia.org/wiki/Osborne_1
| generj wrote:
| Right it clearly was the best choice for the time the
| shuttle was developed but just shows how removed from the
| 1960s and 70s we are today.
|
| My earlier point about payload weight was probably the
| wrong focus. Mission success and maximizing what the crew
| can accomplish in orbit are greatly facilitated by one way
| text from ground control, and doubtlessly paid for the 60
| pounds
|
| Astronauts were already used to Telex weather reports as
| pilots so existing UX. And the crew specialists all had
| PhDs and thus were experts at reading typed paper. So no
| training on yet another shuttle subsystem.
|
| The teletype could be effectively shared between crew -
| just tear off the paper. A portable computer could only be
| used by one or two people, AND would need to be radiation
| hardened and aerospace qualified.
| amelius wrote:
| iPads are more hazardous than you think:
|
| https://appleinsider.com/articles/23/07/14/fatal-
| helicopter-...
| kayodelycaon wrote:
| Not really an iPad-specific issue. A clipboard or
| checklist could have done the same thing.
| dylan604 wrote:
| Maybe they remember the situation with Apollo 13 where they
| had no way to right down the procedures other than by hand
| and using space pages from the existing printed documents.
| You then had the issue where the guys were so fatigued and
| CO2 levels getting to a point of making vision blurry. I
| could see where that might have factored into the decision of
| wanting to avoid all of that with the ability of printing
| new/modified procedures.
| dylan604 wrote:
| too late to edit, but right != write <hangsHeadInShame>
| shagie wrote:
| Remember that this was also before easily portable
| electronics.
|
| Today you'd get a PDF and store it on your iPad. Secure it
| for landing and you're good. All the documents you want.
|
| In the 80s consider the "Mission Control has new landing
| procedures that you need to follow. Here is a 42 item check
| list that you'll need to do before initiating task 357 from
| the mission specification."
|
| How do you get that 42 item check list? Do you write it down?
| What that transcribed properly? Was that a P or a B that the
| person heard over the radio? (Yes, I know Bravo Papa).
|
| Here's a secret objective for the mission ( https://ntrs.nasa
| .gov/api/citations/20110023479/downloads/20... ) to preform
| while in orbit that has now been approved and was not part of
| the initial mission profile. The instructions will be printed
| out and are for the captain and pilots eyes only.
|
| There are a number of reasons that one may need a secure
| printer to handle new documents while on the Space Shuttle.
| With 70s and 80s tech, the approach taken is reasonable.
| KineticLensman wrote:
| > I am fascinated they used 60 pounds and a large amount of
| space for this teleprinter.
|
| IIRC the Zion space habitat in Neuromancer had a state-of-the-
| art line printer which at one point spews continuous-fold paper
| into the weightless environment.
|
| They had however got rid of the slide-rules that were essential
| in early-era Arthur C Clarke spaceships
| throwanem wrote:
| That was _Haniwa,_ not Zion. The printer was spewing paper
| because someone had put a laser through its faceplate while
| Corto was taking the ship.
|
| Also, _Haniwa_ is described explicitly and implicitly as an
| exoatmospheric luxury yacht, and thus likely wasn 't designed
| for high acceleration. Also, I'm pretty sure it was a thermal
| printer, not a line printer as here. Also, _Neuromancer_ is
| period-piece literary sf. So I 'm not necessarily sure how
| relevant it is here.
| KineticLensman wrote:
| In terms of relevance, I was amused that real and
| contemporary fictional spacecraft both had paper printers
| lsllc wrote:
| The question is, would the craft now need help from
| reaction wheels to offset the inertia from the moving
| print head / paper feed? Or would there need to be a
| special version of the printer firmware that kept track
| of its movement so it could always impart equal but
| opposite inertia?
| beerandt wrote:
| The thing that immediately jumped into my head is coded
| military use. Especially since they mention the printer being
| based on a military design.
|
| It's still rather obscure, if not still secret, just to what
| extent we were actually using the shuttles in their intended
| military capacity.
|
| But when designed, the military use was expected to be much
| much higher than what panned out.
|
| This printer would be high on the list of the weight budget, to
| the point that I wonder if it wasn't critical protocol to some
| still secret military use, similar to the teletype nuke codes /
| orders on a sub.
|
| Running over the audio system also makes me curious if it was
| strictly unencrypted comms, or if it could plug in to a
| decrypted steam. Were they clear broadcasting coded messages,
| or encrypted-broadcast clear messages (or both or neither).
|
| IIRC, NASA used to have at least some 'private' comms with
| astronauts that were in the clear, but they basically just
| didn't rebroadcast to the public or publicize those currently
| used frequencies, and just sort of trusted those in the know
| not to listen in.
| kens wrote:
| As far as cryptography, the military AN-UGC/74 teleprinter
| worked with cryptographic equipment such as TSEC/KG-30,
| KG-84, KW-7, and KY-57 [1]. You'd send the data stream into
| the crypto equipment and then to the teleprinter. However,
| the modifications for the Space Shuttle would have prevented
| this. Specifically, the FSK demodulation boards for the
| Shuttle were wired directly to the communication UART board,
| so there was no place to plug in the crypto box.
|
| [1] https://radionerds.com/images/e/e0/TM_11-5815-602-24.pdf#
| pag...
| walrus01 wrote:
| > The thing that immediately jumped into my head is coded
| military use. Especially since they mention the printer being
| based on a military design.
|
| a significant portion of the funding for the shuttle came
| from the USAF, and one of its capabilities (to capture and
| return a large satellite) was a USAF requirement. They even
| went as far as building an entire launch pad for it at
| Vandenberg, which came very close to being used.
| tyingq wrote:
| Here's my guess. Government bureaucracy is probably very high
| for anything space related. So _" based on the military's
| AN/UGC-74"_ could have helped get it through approvals. It
| would have ticked a lot of boxes for ruggedized parts, use in
| harsh environments, and so on.
| beerandt wrote:
| I don't doubt that for a second- but I'm more curious about
| the requirement for some kind of printout in the first place.
|
| Especially since it ultimately ended up weighing what it did.
|
| Military/ Ruggedized is a smart choice for a printer that
| needs to go through that environment, no matter the why.
|
| I'm more interested in what it tells us about the underlying
| purpose (or what it might rule out, like the part about wired
| directly into unencrypted comms).
| tyingq wrote:
| Oh, I didn't consider that, since I was a young person
| then. Sticking notes, directives, etc, everywhere was just
| really common. So if they get a note about extra daily
| checks on equipment X, they print/affix the note to the
| equipment. Or other similar needs. There would probably be
| limited screens, so anything you wanted to be known to
| everyone, becomes a note.
| amelius wrote:
| > At 30K per pound of payload that is $1.8 million per flight.
|
| Yeah, but they could save by using white-label ink cartridges.
| marcodiego wrote:
| X (twitter) is useless for threads unless you're logged in. How
| can I read this thread?
| ghosty141 wrote:
| Yeah somebody should mirror it. In general I dont understand
| why people post things like this on X. Its a horrible platform.
| bookofjoe wrote:
| For some; for technically dumb people like me, it's the only
| platform that's easy to use.
| bagels wrote:
| What are some better alternatives?
| kens wrote:
| Serious answer: I post things on Twitter because it is easy,
| lets a huge number of people read my thread, and provides
| easy interaction. I post the same threads to Mastodon and get
| orders of magnitude less interest. I also write blog posts,
| which take a huge amount of time (a week versus an hour) and
| are hit-or-miss. Sometimes they are very popular and
| sometimes they disappear without a trace.
| dylan604 wrote:
| Might it be that it takes a week because you spend time
| thinking things through in a much more coherent manner
| rather than just submitting stream of conscious level
| tweets? Sounding professional instead of trendy?
| nickloewen wrote:
| I'm always delighted when I visit HN and see one of your
| blog posts on the front page; they posts are great and they
| elicit some of the most interesting HN discussions. It took
| me a little while to realize that all these good posts were
| on the same blog, but once I did I had a lovely time
| browsing through the archive and reading more of the "deep
| cuts."
|
| The posts about the System/360 consoles come to mind, for
| example. I'm not sure how "popular" those were(?), but
| they've been very helpful as references for an art project
| I'm working on!
| nebalee wrote:
| This was also posted on mastodon
| https://oldbytes.space/@kenshirriff/112124283096167861
|
| (I assume it's the same post, couldn't read the one on twitter)
| bragr wrote:
| Can confirm it's the same
| kens wrote:
| Three ways you can read the thread: a) Log into Twitter. b)
| Read the same thread on Mastodon [1]. c) Wait until I turn it
| into a blog post.
|
| [1] https://oldbytes.space/@kenshirriff/112124283096167861
| dclowd9901 wrote:
| Can I ask as a genuine question: why use twitter at all for a
| post like this? I'm not trying to be a Luddite or even just
| anti-twitter. I just don't understand using it for long form
| deep topics like this. And yes I fully understand many people
| do use it this way, and to them I'd ask the same question.
| dt3ft wrote:
| Off the top of my head: Clicks/ Hype/Sharing/Reach.
| kens wrote:
| I answered that question elsewhere in this thread:
| https://news.ycombinator.com/item?id=39768125
| dpifke wrote:
| From the guidelines[0]:
|
| _Please don 't complain about tangential annoyances--e.g.
| article or website formats, name collisions, or back-button
| breakage. They're too common to be interesting._
|
| [0]: https://news.ycombinator.com/newsguidelines.html
| perihelions wrote:
| Wait, do normal printers need gravity to work? If I were to find
| one and flip it upside-down, would it continue functioning
| normally?
| a_gnostic wrote:
| Inkjets need a gas cartridge.
|
| https://www.spacepen.com/our-story
| falkenb0t wrote:
| Not exactly a primary source but according to this thread:
| https://forum.nasaspaceflight.com/index.php?topic=10617.0
|
| "Toner is held to the paper in a laser printer by electrostatic
| attraction (opposite charges attract), not gravity. Along those
| same lines, in an inkjet printer ink droplets are fired at the
| paper, not just dropped, so once again I doubt gravity is an
| issue."
| HeyLaughingBoy wrote:
| But before you even got to the point of printing, the paper
| in a regular laser or inkjet printer wouldn't even feed
| properly if upside down!
|
| I'm also willing to bet that whether or not the droplets are
| "fired" at the paper or not, the inkjet cartridges aren't
| going to work in an inverted position: they might not even
| supply ink in that configuration.
| rtkwe wrote:
| Normal printers probably wouldn't handle the shaking of
| launches and the extra G forces during that which for shuttle
| were ~3Gs.
| generj wrote:
| And when shuttle was developed, printers barely existed. Both
| inkjet and laser desktop printers were introduced
| commercially 1-3 years before the shuttles first flight in
| 1981, and weren't very reliable yet. Desktop printers _still_
| aren't as reliable as a teletype or dot matrix printer.
| There's a reason airlines use dot matrix for printing flight
| manifests at the gate.
|
| Ink plotters, teleprinters, and fax machines ruled the world.
| But plotters are dreadfully slow at writing text. Radio fax
| machines may have been viable if they were rugged enough. But
| they probably weighed as much as the teletype and were much
| slower - only real advantage is printing diagrams and photos.
| bluedino wrote:
| Imagine a printer in zero gravity just spraying printed pages
| around the cabin of the shuttle, since pages don't neatly fall
| into the output tray.
| johnklos wrote:
| An Apple ImageWriter II would work, no matter what. I bet it'd
| work if they were printing DURING a launch.
| scionthefly wrote:
| The only competition it would have would be a Microline
| ML184.
| eigenvalue wrote:
| This is cool but it just makes me think the Shuttle was absurdly
| inefficient across the board. Why waste not just the launch
| weight but the engineering work on making such a specialized
| printer? Aren't we talking about the late 70s/ early 80s? Surely
| there were commercially available printers that could have been
| substituted that would weigh less and wouldn't have the
| overheating issues. Having unlimited government money is
| ultimately a curse for efficiency and performance.
| wildzzz wrote:
| It's overkill for normal office use but the space shuttle is
| going to have some massive vibration and mechanical shock
| during launch. All systems have to be ruggedized to withstand
| the environment. A commercial unit might not survive the trip
| up and building some sort of vibration damping system for it
| might take up more space. If the manufacturer can't guarantee
| the uptime for the commercial unit, they might need a spare
| aboard as well also in its own special dampener case. Sometimes
| it just makes sense to do a custom design that meets your needs
| instead of trying to make a square peg fit a round hole. Also
| the related systems have to be considered. The Shuttle had a
| power bus of 28VDC, were there any commercial printers that
| took 28VDC and had proper EMI filtering? Were commercial
| printers compatible with the types of data signals expected on
| the Shuttle? You may need to build some sort of adapter to make
| a commercial printer work with the data and power systems. You
| may end up with something just as heavy and bulky and still not
| as reliable.
| dylan604 wrote:
| > It's overkill for normal office use but the space shuttle
| is going to have some massive vibration and mechanical shock
| during launch.
|
| Maybe you haven't seen how some delivery drivers treat the
| packages in their care. I swear I've received boxes that look
| like the were shaken, not stirred, to the level of a rocket
| launch.
| kayodelycaon wrote:
| Printers aren't usually shipped in operable condition.
| dylan604 wrote:
| You're suggesting that a printer being launched into
| space on a rocket would also not be secured in a similar
| fashion? What's your point otherwise?
| rtkwe wrote:
| I have doubts a commercial printer back then would handle the
| 3G acceleration and vibrations during launch and reentry well.
| There's also the issue of materials from the safety of them for
| fire risks to potential off gassing you wouldn't notice in an
| office but could cause issues in the enclosed recycled
| atmosphere of the shuttle.
|
| A lot of the cost for space bound items are from R&D being
| concentrated in a few items but others are because it costs a
| lot to make sure they're not going fail or kill someone. Using
| this behemoth saves some of the time by reusing a military line
| printer that was likely already tested for shock resistance if
| it was used on ships and for fire safety for similar reasons.
|
| There's also the potential military uses of the Shuttle which
| informed a lot of it's design. Military printer already has the
| decoding infrastructure if it needs to be built in with known
| key management etc you'd have to build seprately for a
| commercial printer.
| jdblair wrote:
| Its unlikely that it was special-built for the Space Shuttle.
| Obviously this is speculation, but it most likely was already
| special-designed for a military application and just re-used in
| the shuttle. All of those strategic nuclear bombers that used
| to fly on standby 24/7 needed communications, too.
| kens wrote:
| You don't need to speculate. As I explained in the thread,
| the Shuttle teleprinter was based on the military AN/UGC-74
| teleprinter but had many modifications including new three
| circuit boards for the FSK decoding.
| jdblair wrote:
| Ah yes, its right there in the 2nd post! Thanks for the
| correction.
| kens wrote:
| The explanation for why they chose this printer is in a
| conference paper published in the National Telesystem
| Conference, 1982. Unfortunately, I can't find these conference
| proceedings anywhere (even in physical form). If anyone happens
| to have a copy lying around...
|
| [1]
| https://ui.adsabs.harvard.edu/abs/1982ntc..confR...4S/abstra...
| jdblair wrote:
| I couldn't resist searching myself. It looks like there is a
| physical copy of the conference proceedings in a library in
| Japan!
|
| https://topics.libra.titech.ac.jp/recordID/catalog.bib/BA902.
| ..
| Maxion wrote:
| Let's hope the internet can connect us with someone who
| lives near by and has a ibrary card!
| atoav wrote:
| If you trust that office printer to survive a roll down a steep
| mountain sure.
|
| Your idea of how electromechanical devices "just work" is based
| on office environments (and even there they fail with
| astounding regularity today, half a century later).
|
| As an electrical engineer that has repaired many (also very
| old) devices I don't think you have a realistic idea of why the
| thing looks as it does. One point is environmental factors
| (strong vibration, harsh radiation, potential temperature
| differences etc) another one is risk managment. If your
| commercial printer fails, how will it fail? You better know
| _exactly_ what it 's failure modes are, because you are the guy
| who selected that printer and _you_ are reaponsible for both
| the failure of the mission and the potential death of
| astronauts who trust you. Still feel secure about the choice?
| Then you are probably the wrong person for the job.q
|
| TL;DR: look for a certain (recent) submarine failure to see how
| well your approach works in practise
| ajsnigrutin wrote:
| There's a much simpler version of a communications 'printer'
| called Hellschreiber
|
| https://en.wikipedia.org/wiki/Hellschreiber
|
| Some old specimens still work, some new reproductions have been
| made, and it can also be simulated in software with various
| popular ham-radio programs.
|
| ...also, it's used by at least a few dozen hams every now and
| then :)
| gooseyman wrote:
| TIL a space shuttle printer will fetch $8,659 at auction.
|
| https://www.rrauction.com/auctions/lot-detail/34715670664982...
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