Yeah the occums razor argument doesn't apply here. To take both sides for a moment...
If we didn't go, like the guy above me said it wouldn't be THAT hard to hide it. Look at the insane amount of censorship that China achieves in today's information age. The Great Firewall of China, the news censorship, the political censorship. That's over a billion people controlled in a country with the largest number of cell phones anywhere in the world (I think some 300-400M cell owners) and an international economy where information could easily 'leak' into the country. Yet they do it. And they do it well.
http://www.pbs.org/wgbh/pages/frontline/tankman/view/
In the last block they interview internet savvy, very intellegent college students at a University in China. They've never even heard that there was a revolt in Tianenmen Square. No knowledge whatsoever. And that was recent history broadcast around the world.
As an other example, Japan is very selective about what it will teach students regarding WWII. Many Japanese, despite their extreme tech and business savvy, are simply ignorant and unless they actively seek the information, it's not going to come find them. People more or less are happy to be happy, and what they learn they believe.
The idea that something being hidden is so difficult to achieve that therefore it *must* be true is flawed.
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On the other hand, we *were* launching rockets, we *did* go back many times after the initial landing, and some of the times we went back weren't major spectacles like the initial landing. No point 'faking' it if nobody is paying attention. Also the technology did exist then. Many of the rockets launched today were designed in the 60's and 70's (the Titan for example). Most of our nuclear stockpile, and the ICBM's that carry them, were designed during that era.
The technology was there, the will was there, the need to honor JFK was there, and the chance to raise a giant middle finger to the USSR was there. In many ways it made sense to go, and the USSR would be tracking every minute of that flight. If we faked it they would have made every effort to expose us.
--Illah