For those who think we need more power out of the control system...

[Dave Flowerday]

I was browsing SparkFun, one of my favorite hobby electronics sites, today and they had an interesting article on their front page discussing the computers used on the Apollo missions to the moon. Seems appropriate given the name of our game this year!

Anyway, they make the point that the moon landings were driven by a computer that is less powerful than an Atmel AVR (which is itself significantly less powerful than the old IFI system and obviously the new CRIO system). Pretty interesting to think that they could navigate themselves all the way to the moon on 36K of program memory and 2K of RAM. And if it crashed, well, that would have been bad news.

Here it is 40 years later and I'm still amazed by what those engineers accomplished with hardware that would be considered beyond primitive today. It was the pinnacle of ingenuity and innovation. Just think if someone gave you this year's FRC control system and told you to write software on it to control a huge rocket and steer itself all the way to the moon. Talk about a challenge!

Here's the article:
http://www.sparkfun.com/commerce/news.php?id=248

[Uberbots]

To quote some rather frightening specifications:

 Apollo Guidance Computer	ATmega168
 $15M                          $2
 55W Power                     0.055W Power
 ~1 MIPS?                      20 MIPS
 70 lbs.                       0.0022 lbs.

man that took forever to format.
I love that little chip (the atmega)

[DonRotolo]

A slide rule was the accepted calculator. How many of you (under 40) have ever held one? I bought a beautiful 10" K&E log log duplex decitrig, in perfect condition, for $5 at a garage sale 2 weeks ago.

Oh, and the Apollo computers DID crash - kinda sorta. It seems the rendezvous radar was switched on, and the volume of incoming data was too much for it during the last minutes of descent, far exceeding its computational capacity, causing guidance calculations to never be perfromed. To quote:

a full minute's worth of guidance commands were never issued by the computer due to the rendezvous radar!

How would YOU feel if your nav computer was silent (or throwing "1201" and "1202" errors the whole way?) for an entire minute, just before you were going to be the first ones to land (or crash!) on the moon? If Neil Armstrong wasn't the pilot he was, literally flying by experience, they really would have crashed.

I've said it before, I'll say it again: That night watching them land (and later walk) on the moon changed my life.

Don

[EricH]

Originally Posted by Don Rotolo

A slide rule was the accepted calculator. How many of you (under 40) have ever held one?

Guilty! It was my grandfather's back in the day. Still in good condition.