Debugging a Live Saturn V | Hacker News Reader

Debugging a Live Saturn V

zamiang.com

276 pointsdblock33 comments

For those that are not familiar, the Saturn V was equipped with 5 (yes, you read that right)... five F-1 rocket engines. Each engine produced an absolutely staggering 1,500,000 pounds of thrust; that's a total of 7,500,000 pounds of thrust!

Can you imagine being tucked into the small, cramped Command Module, sitting on top of this power at lift-off?

The whole thing, the technology, the sound, the people coming together to make it happen... it's soul-stirring.

https://www.youtube.com/watch?v=y-cv_JJOxGI

A fun wikipedia page:

    18.3 GW – tech: peak electrical power generation of the Three Gorges Dam, the world's
                    largest hydroelectric power plant of any type.
    ...
    190 GW – tech: average power consumption of the first stage of the Saturn V rocket

After that, there are a few lasers that can fire for millionths of a second, but no proper man-made machines. Excluding those experimental lasers, the Saturn V remains the most powerful machine ever made. I have heard that stated a lot, but the truth behind that statement never really sunk in for me before.

Edit: whoops, forgot the link: http://en.wikipedia.org/wiki/Orders_of_magnitude_(power)

Can you explain what "power consumption" refers to in this context? The power released by the fuel to achieve the thrust, taking efficiency into account? Or how is it calculated?

Good question, I am not sure. I suspect that power figure is derived from thrust ("The three-stage Saturn V had a peak thrust of at least 7,650,000 pounds-force (34.02 MN)") and velocity.

This (annoyingly "furloughed") page on nasa.gov has an article written by Wernher von Braun that says:

>"A large stand was built to static-test the huge stage under the full 7,500,000-pound-thrust of its five F-1 engines. These engines generated no less than 180 million horsepower. As about I percent of that energy was converted into noise, neighborhood windows could be expected to break and plaster rain from ceilings if the wind was blowing from the wrong direction or the clouds were hanging low. A careful meteorological monitoring program had to be instituted to permit test runs only under favorable weather conditions."

http://web.archive.org/web/20130216021235/http://history.msf...

180 million horsepower is 134.2 GW, so the 190 GW figure is at least in the same general neighborhood.

You know its big when a rounding error or suchlike can make a 60 million horsepower difference.

Nice estimation. I also don't fully understand how they arrived at 190 GW.

For the purposes of a "back of the envelope" calculation to account for the entire capability of the Saturn V:

Based on the 180,000,000 HP figure, we can (naively) estimate:

Stage 1: 180,000,000 HP (7,500,000 pounds of thrust from 5 F-1 engines)

Stage 2: 27,870,000 HP (1,161,250 pounds of thrust from 5 J-2 engines)

Stage 3: 5,574,000 HP (232,250 pounds of thrust from 1 J-2 engine)

That's a total (non-simultaneous) output of 213,444,000 HP... the equivalent of 159.17 GW (!)

That's simply massive.

https://en.wikipedia.org/wiki/Rocketdyne_J-2

Are you counting the turbopumps needed to fire the engines?

Don't think so, but I don't know if it is appropriate to add those values on either. It should probably be possible to generalize the output of the engines without knowing much about their internal workings, and calculate a power figure just knowing how much they are lifting and how fast.

This stuff is really straddling the line of physics that I remember and physics that I forgot/never learned, so... heavy dose of salt, etc.

The series that that clip is from ("When We Left Earth") is soul stirring throughout. It's one of the most inspirational things I've ever seen. And it's on Netflix! They should really show it in schools, it's incredible.

Link: http://movies.netflix.com/WiMovie/When_We_Left_Earth_The_NAS...

And indeed, Netflix Canada doesn't have it. =(

I'm not even American and I feel a bit patriotic about that shot of the American flag rising up through the condensation and falling ice.

Yeah, it really is an incredible bit of footage. If you can watch the series, though, it makes it so much better, because it really expresses the breakneck pace that these guys were working on. They would go from major milestone to major milestone within weeks or months of each other. I got the sense that they knew very little in the beginning, and basically had ballistic missiles, and they had to become very proficient very quickly to meet their goals.

If you can't see it on Netflix, it looks like it's very cheap on Amazon: http://www.amazon.com/When-We-Left-Earth-Missions/dp/B001BEK...

That's going on my to-watch list tonight. Thanks for the pointer.

If you want to see a Saturn V, this is the place:

http://rocketcenter.com/mu/exhibits

And it is nowhere near the space nerdiest item on display. Von Braun lived in Huntsville, and Redstone Arsenal is where lots of the grunt work was done to put men on the moon.

This very-slow-motion footage of the Saturn V taking off is one of the more impressive pieces of footage I've ever seen. The entire launch process is described in detail, too.

https://www.youtube.com/watch?v=vPW7ZqtW5U4

Watching the entire launchpad engulfed in a fireball is crazy enough. Watching that fireball reverse direction and get /sucked/ down the exhaust hole as the F-1 engines quickly ramp up to that incredible 1.5M lb of thrust is, for me, up there with the photos of Sandia's Z-Machine as evidence that the Cool Sci-Fi Future has indeed arrived.

Signing off on the paperwork and /then/ getting out of there.

So NASA :-)

Careful adherence to a well-vetted plan is a good way to get to the moon and back.

I'd rather not drive a mile and a half away and then find out I missed something on the checklist and have to go back.

And that's what is meant by"Steely Eyed Missile Man."

We know that astronauts frequently have had to be badasses, and even flight controllers have had to be badasses (e.g. John Aaron, Apollo 12, "SCE to AUX"), but this is proof positive that even the guys that fix the bugs in the rockets sometimes have to be badasses, too.

Gene Crantz is another certified badass flight controller, I highly recommend his book "Failure is not an Option" which is all about his time in the American space program (which stretches from Mercury all the way to the Space Shuttle).

Amazing story and many condolences. I hope he was able to personally tell you some of these stories before he passed on.

Awesome. I wish/don't wish that my debugging was that exciting.

i think those situations find you, not the other way around :)

A fascinating story. Although the situation was very different, it reminded me of the aborted launch of Mercury Redstone 1:

"...following a normal countdown, the Mercury-Redstone's engine ignited on schedule at 9:00 a.m. Eastern Standard Time (14:00 GMT). However, the engine shut down immediately after lift-off from the launch pad. The rocket only rose about 4 inches (10 cm) before settling back onto the pad. It wobbled slightly, but stayed upright and did not explode. An odd series of events then took place.

Immediately after the Redstone's engine shut down, the Mercury capsule's escape rocket jettisoned itself, leaving the capsule attached to the Redstone booster. The escape rocket rose to an altitude of 4,000 feet (1,200 m) and landed about 400 yards (370 m) away. Three seconds after the escape rocket fired, the capsule deployed its drogue parachute; it then deployed the main and reserve parachutes, ejecting the radio antenna fairing in the process.

In the end, all that had been launched was the escape rocket. Meanwhile, a fully fueled, slightly wrinkled Redstone and its Mercury capsule sat on the launch pad, both with full batteries and live pyrotechnics. Among these pyrotechnics were the capsule's retrorockets and the Redstone's self-destruct system, which was still active. Furthermore, the capsule's main and reserve parachutes were hanging down the side of the rocket, threatening to tip it over if they caught enough wind..." [1]

[1] http://en.wikipedia.org/wiki/Mercury-Redstone_1

Somehow my occasional entry into the command line on a production server, opening up vi, and snapping a new configuration tweak in place and testing it – it doesn't seem quite so brave or adventurous any more…

What a great legacy to share. Thanks for sharing.

The author humbly failed to mention that late last night he accomplished quite an extraordinary just-in-time feat himself:

Today Artsy launched its live auction platform with TWO x TWO, a charity to benefit AIDS research: http://artsy.net/feature/two-x-two

Making a website is so amazingly far away from the engineering feat of the Saturn V that it's insulting to the Saturn V engineers to make the comparison.

Was referring to the general idea of last-minute fixing mentioned at the beginning of the post: "We all have stories, as engineers, of fixing some crazy thing at the last minute right before the demo goes up."

Incredible story, unfortunately debugging is not that exiting any more..

Since I spend a great deal of my time debugging (I would really say that I spend all of my time debugging), I would say it's a good thing that it's not that exciting.

Beautiful story.

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