[eigenvalue]

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]

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]

> 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]

Printers aren’t usually shipped in operable condition.

[dylan604]

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]

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.

[kens]

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]

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]

Let's hope the internet can connect us with someone who lives near by and has a ibrary card!

[jdblair]

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]

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]

Ah yes, its right there in the 2nd post! Thanks for the correction.

[atoav]

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