Sunday, March 20, 2011

Life Electronic: Straight to the Moon

   Sometimes, it's easy to forget how integrated computers have become in our society in the past few decades. Computers are integral parts of our lives even when we're not aware of it. In such cases, it's good at times to step back and understand some of the things we did before computers were an indivisible part of our lives. Of course much astounding work was done before computers ever really came into the limelight in the 1940s and 50s, but most of it has been repeated and replicated ad nauseam. However, there is a recent event first achieved on July 20, 1969 that hasn't been replicated since December 11, 1972. I am, of course, speaking about the moon landings. One of the most amazing things I find about the moon landings is we were able to accomplish this:
with this:
The astronauts of the Apollo 11 mission carried pocket slide rules with them into space.

   For those unfamiliar with slide rules (I'd wager most of the class has little to no experience with them, I know I've never played with one myself), there are a few things you need to know that make this accomplishment all the more astounding. Most slide rules are precise to two significant digits while leaving enough room for the user to approximate the third digit. Slide rules did not keep track of magnitude; that had to be kept track of by the user. Calculating 4*5 would yield the same result as 4000*0.5. To those of us used to calculators (pocket calculators weren't produced until the early 1970s) and personal computers, these devices seem ancient, almost primitive, but for the daring astronauts of the day, they were enough for many of the calculations the engineers were faced with, from launch to landing.
  Don't think that computers were completely absent from sending men to the moon. Larger batch calculations would be encoded on punch cards are passed through IBM 360s computers. The Apollo Guidance Computer was used on almost every Apollo flight to the moon for guidance, navigation, and control. Two AGCs were used in each Apollo mission, one in the command module and one for lunar module. The AGC was one of the first computers to use integrated circuits with a grand total of 2800 circuits for the logic controllers; even simple cellphones are more powerful than those 70 pound devices and could probably do most of the computer calculations done by every computer in 1969 by itself.
  This achievement is truly a testament to these days. With today's standards of technology and risk management, I'm sure most people would think we were sending those men to their deaths (which I found out was prepared for in case the worst happened and the men were stranded on the moon). Remarkable times for remarkable men.

1 comment:

  1. My father-in-law loves to remind me of this fact! Thanks for a cool post.

    It makes me think of all the things we can't do now, thanks to advanced technology. Most people couldn't fix a toaster if it broke, or a tv. The components in tv's and computers are too advanced, if not toxic, to mess with. So it's not just that it was a simpler time in the 60s, but it was also that we had more independence and more ability to control the technologies around us. It's weird to be in such a throw-away culture where we just have to get rid of things we can't fix (and makes me happy to be married to somebody handy who can fix the things that are still fairly mechanical).

    rant over :).

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