One thing that struck me last time I watched Apollo 13: the slide rule scene. You know, things go wrong, recalculations must be performed, and everyone in Mission Control whips out a slide rule to do them.
Which got me thinking that you could probably perform all the computational requirements of the early moon missions on an iBook. Or a handheld. Or…well, how small a contemporary device could theoretically handle everything NASA’s computers did back in '69?
Does a contemporary digital watch have as much computing power as 1969 Mission Control? Or do we need to get a bit bigger? What’s the smallest device that could handle the mission?
The Apollo Guidance Computer, used onboard to guide Apollo 11 to the moon surface. Of course, you’re asking about the computers at Houston Ground Control.
The Wikipedia page on the Apollo Guidance Computer is pretty good. If I read it right it gives the effective CPU clock rate as 1.024 MHz/12 = 85kHz (complicated instructions took multiple cycles). I couldn’t find much information about the Mission Control computers, but for telemetry they had high-speed 2.4 kilobit/sec data lines.
For comparison, in 1968 the fastest super computer would have been the Cray CDC 6600. (According to Wikipedia )
Now, looking at the specifications, the digital camera I am working with right now (i’m an embedded application engineer) is orders of magnitude more computationally powerful than the CDC 6600 if you consider specialized image processing hardware. Disregarding special hardware the CPU in the camera alone has a roughly ten times the performance of a CDC 6600.
Considering how advanced modern watches can be I have absolutely no doubt that not only could you land on the moon using a modern watch, you could do a lot of other things back then as well. Looking up the specs on the watch linked above, I see it uses a Motorola Dragonball Super VZ 66MHz CPU and has 8MB of RAM. If I had to take an educated guess, I’d say this watch is about three times faster than the CDC 6600.
There are multitudes of factors other than raw computational speed, but trust me, everything has gotten significantly faster and bigger.
I guess this kind watch has a general purpose CPU in it (I thought it pretty much always cheaper to do that nowadays than produce custom hard-wired electronics), though I could be wrong. What would the spec’s of this kind of CPU. And would it be possible for someone with suffient technical know-how and equipment to re-program it to do some general purpose rather than tell the time ?
Awesome. I didn’t really doubt a watch could handle the task, but I was wondering how basic a device could get. The singing birthday card’s a good one.
I don’t know about the specs, but as for programming the watch, it would be…challenging. Since they don’t work off traditional stored programs (and therefore have nothing like a magnetic disk or mass storage device in them) , I suppose you’d have to have a compatible EPROM or EEPROM or something like that which you could use in a PROM burner to enter your programs, then replace the old chip with that one. Again, IF you could find a compatible, programmable chip.
So, my take is yes, it would be possible if you could find the right components, but this would probably be difficult.
I leave it to those microcoders who do this kind of stuff for a living to provide a more definitive answer than mine.
I bet you could do a good deal of it by rubbing two sticks together.
Look at how little storage computers of that era had.* The command module had 78K total, as per bup. I have 1024K built into my laptop’s CPU alone. Having fast storage is essential for doing fast calculations, and being able to fit the entire application plus all of its data into the CPU’s internal storage means things will go extremely quickly. If the landing module’s computer were designed to be built as a modern microprocessor, I’m certain it could fit onto any modern die with enough room left over to build a much better computer around it.
*(With good reason, of course. Creating large-scale reliable digital storage is tough, especially if that storage must also be random-access with fast read/write cycles.)
Very possibly, but all the unmanned probes gettin’ launched off to different parts of the solar system are all computery, and they travel through the radiation belt (however briefly).
