July 16, 2009 marks the 40 year anniversary of the Apollo 11 launch. Four days later, July 20, the Eagle landed on surface of the moon. It all started with the famous speech by President Kennedy. It’s still one of my favorite presidential quotes.
“We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.”
If you are at all interested, be sure to check out We Choose the Moon. This site will be doing a real-time replay of the entire mission. They will include all the transmissions as well as a lot of great information. I know I will be checking the site out often. There also are a few Twitter feeds to follow: @AP11_SPACECRAFT, @AP11_EAGLE, and @AP11_CAPCOM. [update: sorry, I needed to fix the Twitter links]
I was too young to really remember the early landings when they happened, but throughout my life, I read and watched everything I could on Apollo, Gemini, and Mercury programs. I can’t get enough of it. It’s one of the things that got me into science and computers.
Now, 40 years after the launch and a lot of software projects under my belt, I often ponder whether we could land a man on the moon in same amount of time. Kennedy made his speech on May 25, 1961, and Neil Armstrong stepped foot on the moon July 20, 1969 — a little over 8 years. Never mind the political climate and government project differences between now and then, I’m thinking about whether having all the computing power available today would have helped or hurt. Think about it. Apollo worked because thousands of very smart people did the work computers would do today (ironically, today it’s in an effort to use fewer people). The problem is that all that smarts would require mountains of code and would be nearly untestable for all possible cases. As an example, Boeing’s 777 has 2.5 million lines of code to deal with one aircraft. Add in the 3rd party code, and you’re talking about 4 million lines of code. That software project took 4.5 years to complete. The problem is that as complicated as the the 777 is, it’s nothing compared to a moon mission. The number of contingencies to handle in software would be crazy. So, you can try to build a brain to handle everything, or you can park a very smart brain in front of a computer and let them make a decision. Which is going to be more flexible?
Now, don’t get me wrong. A project like this would be a dream, but I also understand that if you wanted to do it in 8 years, you would not be able to automate everything. Too much code, not enough time to test it. As another example, the F22 Raptor project started in 1981, and the plane did not go into service until 2005. 24 years — ouch. I still would LOVE to see it happen though. Maybe this time Mars will be the goal.
Let me leave with one of my favorite calculations done for Apollo. Obviously, to step foot on the moon, you have to get there first. It’s close to 250,000 miles from Earth, but thanks to space you don’t have to run your engine the whole way. All you need to do is complete a forward pass from one moving object to another, but be sure to take into account the gravitational affects of at least 3 celestial objects. Newton would be proud.
You’re in orbit around the Earth, start your engine and get yourself to what speed? What direction? Once you turn off the engine, you will coast for about 3 days, and if everything goes right you will be in lunar orbit. Too fast or wrong direction, and you miss and go off into space. Too slow and you end up a pancake on the moon. With not much more than a slide rule (anyone even know how to use one of these things?), the Apollo scientists calculated lunar orbit to the exact second. Not bad. I know it impresses the hell of me every time I think about it.
Thoughts? BTW, anyone know the equations?