Comment by highfrequency | Hacker News Reader

Comment by highfrequency | Hacker News Reader

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Lots of wise advice. It's telling that one of the most frequently occurring words in this document about landing a man on the moon is "simple."

- "Build it simple and then double up on many components so that if one fails the other will take over. Examples are ablative thrust chambers that do not require regenerative cooling; hypergolic propellants that do not require an ignition source; three fuel cells, where one alone could bring the spacecraft back from the moon"

- "Another important design rule, which we have not discussed as often as we should, reads: Minimize functional interfaces between complex pieces of hardware. In this way, two organizations can work on their own hardware relatively independently...The main point is that a single man can fully understand this interface and can cope with all the effects of a change on either side of the interface. If there had been 10 times as many wires, it probably would have taken a hundred (or a thousand?) times as many people to handle the interface." (interesting proposed scaling)

- "Generally, tedious, repetitive tasks are best performed automatically...but the entire rendezvous sequence was designed so that the pilot could always monitor the automatic system's performance and apply a backup solution if deviations were noted."

- "The single most important factor leading to the high degree of reliability of the Apollo spacecraft was the tremendous depth and breadth of the test activity...Most important of all, the tests gave us a tremendous amount of time and experience on the spacecraft and their systems. Such experience -- together with a detailed analysis of all previous failures, discrepancies, and anomalies -- led us to the conclusion that we were ready to fly a lunar orbit with Apollo 8"

- "Throughout Apollo, many discrepancies or failures occurred daily...the result was the same: The failure had to be understood and, if applicable, some corrective action taken.

- "Pay particular attention to what seem minor details, especially for substitute parts and 'explained' failures."

A lot of this advice can be applied without much additional cost, too!

Whenever one of these "engineering lessons you could learn from aviation (or spaceflight)" threads comes up, there's always a few people who come out of the woodwork with the tired old "LOL aerospace has infinite budget" excuse. Yes, some things in aerospace are cost-prohibitive to bring to your company that does CRUD apps, but things like simplicity, minimizing interfaces, automation and so on probably wouldn't cost as much as you imagine. That hot mess of 50 microservices talking to each other through 20 layers of abstraction and frameworks in your code base probably cost more than a simpler one would. And things like attention to detail, thorough defect analysis and so on are more of a culture change than something your company has to pour money into.

As someone who used to work in the marine and aerospace industries, joining a "normal" application development company was a bit of a culture shock. It took some adjusting to what passes for Quality Assurance, Failure Analysis, Robustness, Stability, in regular commercial software.

Any resources you'd recommend for learning those principles/standards used in more "rigorous" fields? thanks :)

OP’s article is a good start. For avionics, look up DO-178C, Software Considerations in Airborne Systems and Equipment Certification.

Speaking from experience with software engineering which might not apply everywhere, but complexity is one of those things that’s often easy to point out and very difficult to get rid of. It’s often a form of organizational disease where a ton of people’s jobs are tied to maintaining or introducing new complexity - once it becomes entrenched, watch out. Requires good (and rare) leadership to pull out of this.

> Examples are ablative thrust chambers that do not require regenerative cooling

Now imagine that there’s already a team with a vested interest to make regenerative cooling work no matter what. The real puzzle is how do you get them to stop working on it altogether gracefully without hurting too many egos or careers.

I have a feeling that Apollo had a different culture in the early days that was focused on the mission, and these problems didn’t show up. This is often true of early stage startups as well.

Man. Moon. Decade. That was the goal. It was achieved.

It was a dead end. Cost per launch was so high that nobody ever went to the moon again. All that technology was special purpose and single use, not useful for much other than moon missions. Apollo didn't lead anywhere.

> All that technology was special purpose and single use, not useful for much other than moon missions. Apollo didn't lead anywhere.

To the contrary, the lineage that underpins modern computing traces directly back to Apollo and the work that supported the program. Apollo was a force multiplier in going from “adding machines running on buildings full of vacuum tubes” to solid state technologies and running higher level software that could control hardware.

Similarly, what we learned about building human-rated spacecraft directly led to the follow-on programs, some of which would become ISS.

Many of these advancements would be synthesized into modern defense, weather forecasting, and other technologies. The need for NASA to interconnect facilities far afield from one another was a huge force for advancing what telephony and telematics could do.

Apollo wasn’t meant to go beyond the moon, but that doesn’t mean it didn’t go anywhere. Apollo accomplished what it set out to do and became a scientific foundation for the next several decades.

> To the contrary, the lineage that underpins modern computing traces directly back to Apollo and the work that supported the program.

No, that was mostly the USAF, not NASA. At one point, the USAF was the largest buyer of transistors. There were transistorized computers as early as 1953. The USAF had a transistorized computer in a plane by 1955. DEC was founded in 1957. The Minuteman missile (1962) had a digital computer onboard.

And no, NASA did not develop Velcro, Teflon, or Tang, either.

I didn’t claim that NASA invented transistor based computers, nor did I claim they developed Velcro, Teflon, or Tang.

In the strictest sense, academia and industry developed all of those technologies on a practical level for some amalgamation of NACA, USAF, and NASA programs.

What NASA accomplished with Apollo was something that the USAF wasn’t positioned to do, which was to transform nascent technologies into platforms that went on to be commercially viable. Apollo straddled a line between what existed, what was possible, and what could be applied without compromising national security during the Cold War. Truly digital computing has its roots in Apollo as a result of the need for telematics and communications that could span half the planet and to the Moon.

There is some fantastic reading on the topic that may interest you. Digital Apollo is a wonderful history, and the NASA NTRS and NASA History repositories online have an endless supply from the banal to the executive.

Recently I enjoyed the coffee table book Core Memory, edited by Mark Richards. It’s a fantastic visual survey and light history of specific computers from the past and includes some of the USAF/SAC hardware, including an ARPANET Interface Message Processor, as well as the Apollo GNC. Great to flip through if you also enjoy viewing these legendary pieces of hardware.

Edit: I misread your comment initially; I see you didn’t claim that I said NASA invented transistor based computers. I submit that it’s a nuanced point, although I’ve also been long fascinated by that earlier work by (e.g.) Bell Labs, Draper, MIT MVL, and so on.

  > Most important of all, the tests gave us a tremendous amount of time and experience on the spacecraft.

Surely they mean man-hours and not aggregate time. Apollo 8 was only a year and a half after the Apollo 1 fire, and much of the spacecraft was redesigned afterward.

I think they meant aggregate. Remember that most of the people leading the Mercury/Gemini/Apollo charge had WWII experience. Safety was based on "at least nobody is currently shooting at us" and development cycles were influenced by the fasttrack programs during the war. Similar trends happened in other areas (motor racing). Those with wartime experience just shrugged off safety, accepting danger as they did during the war.

Completely tangential here, but there's an important exception to the Keep-it-simple-stupid rule. It's Admiral Rickover's nuclear reactors. He looked at all the options and decided that there's just no way to "keep it simple". He decided that his reactors will be what they'll need to be, and the operators will be extraordinarily well trained so that accidents don't happen. There's a well known Rickover diatribe [1] where he goes on a rant against know-it-alls who propose different designs that work only on paper. It gets posted on HN regularly, I won't quote it again.

[1] https://whatisnuclear.com/rickover.html

"Build it simple"

I once heard a story from a NASA employee. She said that regular ballpoint pens don't work in space due to the zero gravity. So she said NASA got some engineers to develop some sort of fancy ballpoint pen that would move the ink even in zero gravity.

She said the Soviets just used pencils.

And pencils are famously dangerous in space. Graphite is a conductor. You don't want conductive dust floating around a pressurized chamber filled with electronics, oxygen and people.

There are lots of little health details about zero gravity, things that literally never come up on earth. Dust is a big one. Dust doesn't settle to the ground in space. You end up inhaling it. Graphite (also glass) is not the sort of things you want to inhale.

Yeah that's probably why the soviets (and the americans) used grease pencils instead of graphite pencils in space.

The absurdism of this pencil/pen lore goes so deep that even the corrections can't get it right. Seriously does everyone just assume that people in the 60's were that stupid?

It’s a compelling story that’s fun to tell at parties. These are often 90% untrue. Seriously think of any historic “fun fact”, it’s probably mostly false.

The reality is much simpler. Pencils suck for long term record keeping. Grease pencils especially. A guy developed a space pen and asked NASA if they wanted it. They tested it and it worked pretty well, so they ordered a bunch. The Soviets then bought a bunch too by the way! But yeah that’s not nearly as fun as “dumb rich Americans over-engineer everything”.

During the space race, it was actually America that pioneered drinking alcohol in space.

https://www.theguardian.com/commentisfree/belief/2012/sep/13...

> Seriously does everyone just assume that people in the 60's were that stupid?

Most people assume history is about getting smarter and better; That bartering changed to trade with seashells because currency is smarter. They don't understand the supply chain, and the difficulty of obtaining enough quantities of calcium carbonate to construct city walls. They don't understand that people can't economize on things they don't know. They think /dumb/ is synonymous with /ignorant/. Some do learn the difference, but choose to remain /stupid/ by assuming past people were dumb, instead of making the best out of what they had and knew.

No, it's just a meme about how Americans are supposedly nerds who overengineer things while Russians are supposedly commonsensical manly alcoholics.

This is an urban legend.

https://en.wikipedia.org/wiki/Space_Pen#Uses_in_the_U.S._and...

Yet they sold me one of those space pens in the cape canaveral visitor center in 2000…and it‘s a really good pen, works as advertised upside-down, and is still working. I like to use it when I sign important papers.

The urban legend is not that such a pen exists. But the part about the pencils and the part that NASA paid their engineers to develop the pen. The Fisher pen was developed using private capital, not government funding. It was later used by both NASA and the USSR.

You made it even worse by quoting an urban legend and trying to pass it as personal experience.

Also, graphite shavings are bad for your lungs and they float everywhere in low gravity.

This was personal experience, it’s really not necessary for you to call me a liar.

https://www.zmescience.com/feature-post/space-astronomy/spac...

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