Debugging a Live Saturn V | Hacker News Reader

Debugging a Live Saturn V

zamiang.com

123 pointsjlangenauer35 comments

If you like these kinds of stories, Boris Chertok's memoirs have a lot more from the Russian early launches during the space race. He was in charge of electrical systems in many of the Russian rockets.

NASA history has an excellent four volume translation of his memoirs. In volume 2 he describes the development and testing of the R7 (Soyuz) rocket:

https://www.nasa.gov/connect/ebooks/rockets_people_vol2_deta...

That makes me remember some interesting things I read that explains how much of the space race went:

In the immediate post-WWII era, the US had lots of experience with long-range heavy bombers, and plenty of air bases close-ish to the USSR. So the US focused on delivering nukes via aircraft and neglected rockets at first. The Soviets weren't real into long-range heavy bombers, and didn't have many air bases near the US anyways, so they went in on long-range rockets sooner and harder. Their nuclear program was less developed too, so their bombs were bigger and heavier. This means that their long-range bomb delivery rockets were big and powerful enough to double as orbital rockets with minimal changes. US bomb delivery rockets were significantly smaller, so we needed to develop all-new rockets to start launching things into orbit.

The Soviets were also behind on electronics and automation. When they wanted to do orbital surveillance and intelligence gathering, they put actual humans in their satellites to do it. The Americans decided that it was better to use electronics to do the same job. It was indeed better to use electronics for the purpose of surveilence, but that also meant that the Soviets racked up a lot of experience in running manned space stations that we didn't start to touch until much later on.

Source: https://selenianboondocks.com/2019/05/amistics-of-human-spac...

They were given permission to take that long list of risks because of the urgency of the space program. I don't think anyone would dream of sending people into a flammable, toxic atmosphere for electrical work these days. And that's how we got to the moon.

> And that's how we got to the moon.

With only three dead (due to the use of flammable atmosphere!) and the narrow escape of another three. Better results than the average WW2 bombing mission, I suppose.

Honestly I think you would find thousands of volunteers to do space exploration with a much higher risk than we are willing to entertain today.

I sometimes wonder just how much we are handicapping ourselves as a civilisation with the risk averseness we take to some tasks while being pretty blase about others where the reward is nowhere near as high.

I would argue the bigger handicap is the resource constraint for large projects - from lack of funding as well as lack of resources since the major sources Of taxable income (Amazon, Apple, etc) don’t pay tax.

Resources are a choice. Nobody ever did a cost-benefit assessment for the trillion dollars of Iraq war.

(Arguably the space programme worked as a proxy war with the Soviet Union; America didn't want to let the Russians ""invade"" the moon first.)

Apologies - not sure I understand. But I think I agree that societies choose how to distribute their resources?

I suspect the risk avoidance is simply a political necessity. In the US, ever since the Apollo program ended NASA has to fight for their budget, they can't afford highly public deaths for fear of entire programs being cancelled.

Meanwhile Russia's space program is mostly noteworthy for being a reliable launch provider with one of the most reliable rockets ever built. With no budget for bigger ambitions and little competition until recently there was no incentive to change anything.

I doubt it's about what the astronauts themselves would consent to. It's about congressional hearings, what the talking heads on MSNBC and Fox News would say, and what all of that might mean for the lives and careers of many thousands of additional people who have no intention of going into space themselves.

ISTR the acceptable risk statement for the Apollo program was that there be no more than a 20% chance of losing a crew.

NASA lost the Apollo 1 crew in the pad fire, nearly lost the Apollo 13 crew, and lost a bunch more astronauts to plane crashes in the early days. They also nearly lost the Gemini 8 crew during the docking accident, and nearly lost Gus Grissom when the hatch cover pyros blew unexpectedly after his Mercury capsule splashed down. (On the other hand the attrition rate among test pilots in the 1945-1975 era was sky high.)

Then there was the Shuttle, which was supposed to have a less than 1% chance of losing a crew and managed to kill 14 astronauts in 130-something flights (and had a couple more very close calls).

Even the best/safest crew launch vehicle to date -- Soyuz -- killed four cosmonauts (on Soyuz 1 and Soyuz 11) and had a couple of extremely hairy launch aborts and uncontrolled ballistic re-entries.

TLDR: nearly 60 years after Gagarin's flight, human space vehicle launch and re-entry is still extremely dangerous. (Living on a space station: somewhat less so, but still not as "safe" as the crew of a nuclear submarine.)

> Then there was the Shuttle, which was supposed to have a less than 1% chance of losing a crew and managed to kill 14 astronauts in 130-something flights (and had a couple more very close calls).

That seems like a misleading way to frame it. It was 14 astronauts out of 833 who flew, or 2 crews out of 130, so 1.5%. Not far off the estimate. And with that high a percentage, a number close calls are also expected.

I thought all of the Nitrogen gas sounded much more dangerous. It's scary easy to die from nitrogen suffocation without even realizing anything is wrong until you're basically unconscious.

Switching a relay in a flammable atmosphere is ... bold. Does anyone know what voltages were used?

Edit: Seems like 28 volts DC unregulated supply (https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/197400...), which was regulated to 5V and 56V depending on where it was used (https://en.wikipedia.org/wiki/Saturn_V_instrument_unit#Power)

Was it a flammable atmosphere? Liquid oxygen would have been venting, but there shouldn’t have been any significant fuel in the air.

-Given sufficient oxygen levels, anything is fuel - including engineers...

Well sure, but a tiny spark in a relay isn’t going to ignite the engineer.

It might ignite the metal in the relay, before igniting the engineer.

-Not necessarily - there's a bunch of ATEX Ex relays in my desk drawer. Conventional, not solid state ones - they are just put in some potting compound, hermetically sealing them.

This reminded me of a recent post about how we can’t do anything fast anymore.

https://news.ycombinator.com/item?id=21848860

This kind of daring/insanity that can only be justified as part of something as important as the space race is possibly part of the reason.

"We resealed the cabinet, signed off on all the paperwork and got the out of there without any more sight seeing."

That's the NASA spirit!

Now I think of it, of course they used switching relays in the 1960s. But...I am astonished that they worked in such a high-vibration (and extreme temperature) environment.

The entire enterprise remains incredible, and the more I learn about it the more incredible it seems.

That's because it was actually all a hoax. ;-)

EDIT: Wow, HN really has zero tolerance for ironic humor.

I thought "NASA will have a spec for this", and sure enough a bit of Googling finds this from 1973: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/197300... which references "Teledyne 422" relays. That is https://www.teledynerelays.com/Datasheets/420422.pdf , which claims 30g at 3000Hz. Apparently by using strong fields over short distances.

(The first PDF is worth scrolling to the end for a full set of neat hand-drawn mechanical and circuit diagrams. No CAD back then!)

Latching relays don't need to rely on field strength to hold contacts in place. Then it's just a mechanical design problem.

In launch phase they presumably had plenty of power; I was thinking of mechanical chatter (rising) in the contacts.

Those are still available, but as expected, not cheap:

https://www.mouser.com/Teledyne-Relays/Electromechanical/Rel...

They are around $100 each.

All the tables and forms were typed and likely re-typed as well. Photocopiers did exist but were uncommon.

OK, men, you're about to service a fully fueled Saturn V rocket that is spewing all sorts of nasty gases and is an active spark away from blowing up itself, and you, over a 5 mile radius.

Do you all have your plastic safety helmets?

Amazing story, a once in a lifetime experience for sure!

One in a lifetime, in a GOOD way.

I love stories like these. Are there any more from engineers of the time? Perhaps, are any more of his stories published anywhere?

The best place to start is Apollo by Murray/Cox: https://www.goodreads.com/en/book/show/282086.Apollo Rather than focusing on the astronauts, this is very much a story of the engineering and management that made the project possible.

From someone who helped develop the lunar lander, there's Thomas J. Kelly's "Moon Lander: How We Developed the Apollo Lunar Module": https://www.amazon.com/dp/1588342735/

Another good book (so I've heard - I own a copy but haven't made time to read it yet) is Sunburst and Luminary by Don Eyles, who worked on the guidance system at MIT: https://www.sunburstandluminary.com/SLhome.html

For deep technical details (but light on first-person stories), there's How Apollo Flew to the Moon: https://www.goodreads.com/book/show/2323178.How_Apollo_Flew_...

Finally, not strictly related to the space race, but for some truly wonderful first-hand tales from the development of rocket propellants, you can't beat John D. Clark's Ignition!: https://www.amazon.com/Ignition-Informal-Propellants-Univers...

What a wonderful story - and a great way to honour and remember your grandfather.

One of the best stories this year. Thanks for sharing

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