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How NASA brought the F-1 “moon rocket” engine back to life (2013) (arstechnica.com)
80 points by jedberg on Jan 6, 2015 | hide | past | web | favorite | 16 comments

A superb promoted comment from a "ws3"

Imagine you're a Rocketdyne engineer in the 60's and one day, some guy walks out of a time warp into your assembly area, pulls out some weird looking cameras, takes a few pictures of your engine, plugs some cables into some unknown equipment, and then, looking bored, sits down and directs his attention to a thin metal and glass slab for a while. When a light changes on the unknown equipment, the guy gets up, sticks his hand inside, and pulls out a tool which takes apart your engine.

That would be magic. You'd think the guy was from the 25th century or something. But no, only 45 years.

I've always known intellectually that the Saturn V was an absurdly powerful rocket, but I think this is the comparison that really drove it home

> [T]he power output of the Saturn first stage was 60 gigawatts. This happens to be very similar to the peak electricity demand of the United Kingdom.

Yes, but how many (American) football fields is that ?

This is a really amazing article. And to readers who are reading the comments first: please don't be discouraged by the negativity. Just go ahead and read it first.

What I thought strange was that they would have to reverse engineer something that they themselves built? That sounded pretty strange to me. But the article clarifies this point:

"A typical design document for something like the F-1, though, was produced under intense deadline pressure and lacked even the barest forms of computerized design aids. Such a document simply cannot tell the entire story of the hardware. Each F-1 engine was uniquely built by hand, and each has its own undocumented quirks. In addition, the design process used in the 1960s was necessarily iterative: engineers would design a component, fabricate it, test it, and see how it performed. Then they would modify the design, build the new version, and test it again. This would continue until the design was "good enough.""

We try very hard to do better, but even know this is the normal state of all manufactured products everywhere. One other problem is that mechanical design documents don't have good places for "why is this this way" type comments.

These techniques are the future of reverse engineering and product customization.

This makes me wonder if it will be possible to reverse engineer some of the complex things we're building today.

I think the answer to that is "yes", since our technology is advancing all the time. The question this made me wonder about is, "If this new 2015 engine was given to the 1970s engineers, would they be able to understand how it was made and create a similar one?" This is just 40 or so years later. It makes you wonder how advanced an alien civilization would really have to be to impress us.

They'd realize that some kind of new technique was being used to fabricate complex free-form parts. After close examination of the metal, they'd discover it was a sintering process, because sintered metal has a recognizable structure. They'd quickly figure out it was built up layer by layer by some deposition and heating process, because the layers are visible. Lasers were known in the 1960s. Even kilowatt-sized lasers existed in the 1960s, although they were big and involved chemical reactions. Numerically-controlled milling machines were known, although they were really clunky and usually involved paper tape readers, rather than direct computer control. Scanning electron microscopes were available by 1971, so it was possible to look at the fine structure of a chunk of metal. So the whole process might have been figured out. With enough money, laser sintering might have happened in the 1970s. It was actually invented in 1981, by a grad student looking for a project. (http://www.me.utexas.edu/news/2012/0712_sls_history.php) It took a long time before it worked well, but that could have been accelerated with money.

Making a model by laser scanning with structured light was a known process in the early 1970s. It was used by Ford Motor to get from clay models of cars to metal dies used to stamp out body parts. Previous approaches involved plaster casts and mechanical tracing machines.

However, a computer tablet was beyond 1970s technology to even analyze, let alone duplicate.

>However, a computer tablet was beyond 1970s technology to even analyze, let alone duplicate.

I doubt they'd be able to duplicate it, since there's a whole manufacturing infrastructure they'd have to duplicate first. But I doubt they'd have any trouble analyzing it. By 1970 they had integrated circuits, and there were people who were already looking ahead to the possibilities. It's not that hard to pop the plastic off of an IC and look at it with a microscope.

Based on the gestalt of the time, they'd probably look at the tablet and think you should have something more advanced by 2015.

They'd also immediately recognize what the tablet was, and anyone who was familiar with The Mother of All Demos or Xerox PARC's work would recognize the linage.

And wonder why the UI was so inconsistent ^_^.

As for ICs, the "standard" 7400 series dates back to the mid-60s: https://en.wikipedia.org/wiki/7400_series They'd be impressed by the surface mounting, but that's not a great leap from through hole DIPs. They'd be really impressed by the CPU, since computing resources were so hard to get back then, but putting it all on a single chip is obvious, and e.g. the 4004 dates back to late 1971. Even DRAM dates back to the mid-60s (IBM), with the 1103 (Intel's first DRAM, a whopping 1024 bits) being sold stating in late 1970 (albeit with low yields for a while).

Anti gravity engines. Warp engines. Replicators like those of Star Trek.

I want to complain about the fact that I read this a year and a half ago, but since I just reread the entire article, I'll just say: neat!

NASA is reverse engineering an old staged combustion engine. It is good of course, building a computer model, test firing the turbo-pump ... fun learning exercise ... leading nowhere (cheese shop?) While Musk has produced a new from scratch staged combustion engine and is working on full flow stage combustion. Because Musk's enterprise has specific goal, like actually flying to space where is NASA doesn't have such (NASA produced F1 when they did have real goal :).

The F1 is not a staged combustion engine; it's a stock-issue gas generator -- as are the Merlin engines on the current generation of SpaceX rockets. SpaceX is working on a staged combustion engine (the Raptor) for their next generation of very-heavy-lift rockets, but plans for those are still in flux.

It's so true! NASA is suppose to be working towards "Deep Space" flight, but SpaceX seems to be beating them at that too! The Engines Musk is working on are based on the F1 and he is revolutionizing them by using 3D printed metal components and reusable rocket motors.

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