That's the problem though, it IS the only way it can be.
Let me break it down simply for you...
Take the amount of people who work either for NASA or some other space, or geological, or atmosphearic industries (oh, and throw in electrical enginers and GPS companies just for fun). Now, subtract the amount of people just in those areas that are involved in the conspiracy.
I don't know how many people work in those combined areas but I'm going to guess the number is pretty high. Significactly high in fact, even after removing the people who are keeping FE a secret. Just that fact alone makes it a mathmatic improbability, combined with chaos theory it becomes impossible.
I'll break it down into small scale now:
3 people cannot keep a large secret from each other - i.e. married man has an affair, wife WILL (for the most part) find out (it's only a matter of time), usually due to a silly mistake from the husband.
That's 2 people trying to keep one secret from one person, very difficult to do.
Try this, one person cannot keep a secret from many people. I'll explain:
Murder. Do I need to spell this out? Two people know something, one is killed by the other, people investigate, eventually the murderer gets caught. He can't hide all of the evidence of the crime all of the time from all of the experts.
Take those examples and expand them to include the industries I described before, now apply the same rules but make all of the people smarter and harder working. Their job usually consists of defining, refining, explaining, discovering and other '-ings' that scientists and enginers do. They are TRYING to find out secrets.
Even a few people cannot hide a secret this large from many people who are trained to think outside of the box.