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Comment by tdicola | Hacker News Reader

The thing that really shocked me about the Apollo missions was how quickly they jumped from testing the hardware to actual mission to the moon. The _second_ manned launch of Apollo (and _first_ manned launch of the incredible Saturn V rocket) went straight out to the moon and orbited before returning back to Earth! The next missions did a few tests of the lunar lander in space, and the fifth manned mission was Apollo 11 which finally landed. Crazy to think of all the systems, hardware, etc. that just had a couple shakedown flights before the real deal. Incredibly impressive engineering to pull off such a feat without more problems.

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There's a nice parallel there to the construction and launch of individual rockets, as described in another story on the homepage[1]. Many rockets are essentially designed to be single-use, so they can't be put through too much stress during testing. Therefore missions are essentially flown with completely new, largely untested rocket hardware.

The work-around is to build two identical copies of the rocket. The first is a test unit which is tested to failure; the second is put through a very brief test to confirm that it appears to behave sufficiently similarly to the first, and then it's put into service.

[1]https://news.ycombinator.com/item?id=8060031

I recommend Apollo by Cox and Murray, an account of the Apollo program from the perspective of the engineers and managers, written based on hundreds of interviews and archive material. It's fascinating and explains how decisions like this were made in detail.

I second that recommendation. The book can be found for cheap, plus there's even a kindle version if you prefer that format:

http://www.amazon.com/Apollo-Charles-Murray/dp/0976000806/

Along those lines, the first ever detonation of a nuclear device was 21 days before the bombing of Hiroshima.

http://en.m.wikipedia.org/wiki/Trinity_(nuclear_test)

Which was only 7 years after the discovery of the phenomenon of nuclear fission.

And was an untested design.

They actually could've done it in 4 shake down missions. Apollo 10 was under fuelled for fear the team might attempt to land on the moon before Apollo 11 to achieve the record. They did everything except for the actual moon landing portion of the mission.

Even more shocking is the fact that today's cell phones have more computing power than the Apollo computers had - talk about optimizing your code! Just think of the code reviews those developers went through.

And, all the work that the Apollo program brought forth with physics, electronics, etc has powered decades of innovation.

Forget cell phones, your keyboard has vastly more power than the Apollo computers.

The power sequencer I worked with recently for an embedded system was a 16Mhz general purpose 8-bit processor with a bunch of 16 bit instructions and 24 bit addressing.

It cost 17 cents; I'm guessing this is a fraction of the cost of a single BIT of the Apollo computers.

I assume you're aware, but for the general audience: Every bit of memory on space shuttles was an individual physical bead stored in a hand-woven wire grid, with memory contents stored as magnetic orientation. This style of storage was the only available at the time, but continued through the 80's for robustness. No power to maintain memory, and practically immune to bit-flips caused by cosmic radiation.

http://en.wikipedia.org/wiki/Magnetic_core_memory

The article states that the price of a single bit varied from $1 to $0.01 USD over the product lifetime. I would assume that NASA paid extra for higher reliability. 17 cents for a single bit is well within the cost range of a single bit, and a reasonable estimate for that time period.

... jesus tap-dancing christ, a whole dollar for a single BIT? Wolfram|Alpha says that a dollar in 1955 would be worth almost $9 today. The memory in my desktop would be worth more than the GDP of all but 10 US states o_0

The Apollo memory, which was rope core memory, was also known at LOL memory, or "little old lady" memory, since it was women, with their quilting, knitting and crocheting skills, who wove it.

http://news.bbc.co.uk/2/hi/technology/8148730.stm

"a whole dollar for a single BIT?"

Talk to people who fool around with homemade relay based computers or guys like me who just draw schematics and then visit your typical supplier like digikey or mouser and search for 12 volt coil latching relays, which are basically elecromechanical single bit storage devices (aside from other more "practical" purposes).

You're looking at a good $4 to $7 bucks. Per bit. Non-aerospace rated. Made in China not USA.

This is why core memory was popular, being a lot faster, smaller, and cheaper.

"have more computing power"

Unfortunately that means nothing. That would imply someone with control over an iphone (apple, etc) could do "more" than the apollo, which is obviously not happening.

Real power is what you can transform those computations into. Obviously the Apollo computer was far more powerful because it could transform those calculations into landing on the moon and returning, whereas a comparatively powerless iphone can, by itself without infrastructure, do little more than play Angry Birds.

If you're trying to land on the moon, or mars, an iphone is utterly useless and doesn't have even a fraction of the "power" required. It just can't do it. Doesn't have the I/O or the reliability required, not to mention the lack of software.

It is very much an apples and oranges comparison.

> Obviously the Apollo computer was far more powerful because it could transform those calculations into landing on the moon and returning

I'm afraid you aren't looking at how the system went together. The landing process was manual. Remember this was 1969, when there were still elevator operators (though they were by then redundant), steam trains in regular service, etc.

You can read the cockpit transcripts of the landing and compare those to the cockpit transcripts of a modern plane. Armstrong was making burn decisions HIMSELF based on what he saw out the window and what Aldrin was choosing HIMSELF to tell him mattered (Armstrong couldn't see the instruments; Aldrin couldn't see out the window. Astonishing teamwork!)

You can also read the source code for that computer program. Essentially it was a slide rule doing coordinate translation and some instrumentation monitoring. But the fact that they landed with the computer non functional tells you its role in the process.

This is hard to appreciate now when we have computer modulated machinery (stability dynamics in your quadcopter, machine control of your brakes etc) and even materials (both in design, manufacture, and even dynamic control of some beams etc). But back then they couldn't do that kind of thing.

I disagree. I think that if you took that Apollo computer and removed it from the spacecraft, it would have the same amount of computing power . You are correct in pointing out that computing power is not the same as the ability to change the world, but that does not make it meaningless.

Also, you could write the appropriate software and connect the appropriate equipment to the phones I/O port and use an iPhone to land a spacecraft on the moon. It does in fact have the "power" required.

There are both wheeled robots and quadcopter drones that are controlled by phones, you can buy a kit to make them. I don't know whether anyone's done anything particularly impressive with them, but it's certainly possible.

Reminds me of that bit in Iron Sky ...

(not gonna spoil it for those who haven't seen it, it's a totally hilarious film about Nazis on the dark side of the moon, just go watch it)

Is there a github repo of that original code?

The post-hoc analysis of that could burn down the internet for weeks.

I don't know of a github repository, but the source code can be found on the Virtual AGC page. Colossus is the command module program, while Luminary is the Lunar module program.

http://www.ibiblio.org/apollo/Colossus.html http://www.ibiblio.org/apollo/Luminary.html

This is really cool. Here is PLANETARY_INERTIAL_ORIENTATION.agc which contains Apollo command module code for converting between vectors in earth or moon based coordinate systems and a basic reference system: http://www.ibiblio.org/apollo/listings/Comanche055/PLANETARY...

It really looks surprisingly similar to modern assembly code. Well commented too.

Nice. Fun to take a glimpse into the code. Random line:

    	TC	IBNKCALL	# FOR SATURN INTERFACE AND FDAI DISPLAY

The Chinese have a very "measured" manned space program. They launch about every three years. They make a lot of progress between launches. I dont know if its finances or careful engineering. They have the advantage of two previous space programs to study. And they arent racing anybody.

This is actually the only compelling argument in favor of the landing being a hoax. Too much progress too fast with a bit too much disregard to astronauts' lives.

>> Too much progress too fast with a bit too much disregard to astronauts' lives.

We live in a much different world today. Back then if someone died (and some did) they were heros, lessons were learned, and we moved on. Today everyone is so afraid, even the military has a low risk tolerance. But remember how WWII was won, on D-day they basically thew bodies at the enemy to achieve a foothold. People did what it took to achieve goals, even at great cost in dollars or lives. It's just not like that today so it seems rather unbelievable.

I just read a book [1] which argues that while the Americans didn't worry too much about getting the most they could out of their manpower on D-Day - because they had several million more troops waiting to go - the British were conscious of their limited manpower and so optimized their landing in a number of ways, such as longer aerial bombing and specialized tanks for breaking through obstacles on the beach.

[1] http://www.amazon.com/Engineers-Victory-Problem-Solvers-Turn...

Interesting to note that with our increased fear, things didn't get much safer. 1.5% of all shuttle launches killed their crews.

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