

How NASA brought the F-1 “moon rocket” engine back to life (2013) - jedberg
http://arstechnica.com/science/2013/04/how-nasa-brought-the-monstrous-f-1-moon-rocket-back-to-life/

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hga
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._

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bpodgursky
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.

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ovi256
Yes, but how many (American) football fields is that ?

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pm90
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.""_

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nialo
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.

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

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

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dmethvin
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.

~~~
Animats
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](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.

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tsotha
>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.

~~~
hga
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](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).

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kchoudhu
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!

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trhway
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
:).

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rst
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.

