I seriously doubt that a private company could have put a man on the moon within 10 years, and that's what NASA was born from. And from NASA, entire industries have evolved, and research that was done specifically for NASA has been used for other purposes. Sure, maybe most or all of those advances would have been made solely by private enterprise, but not nearly as fast, and probably not nearly as diverse. The US is the undisputed high tech leader in the world, and it's largely because of NASA.
The $5 figure is a general figure. If you look at the return directly out of NASA, the dollar figure is in the hole, huge, probably get back a dollar for every $10 spent. But if you look at all the collateral evolution (like the microchips and all of the things in use today that utilize the technology, and medical imaging and computer graphics), as one study showed, it's more like $25 back for every $1 spent.
NASA isn't perfect, never had been, but I would argue that even with the cost overruns and failures, NASA is more responsible with it's budget than any other government agency. But even looking at it as a pure loss leader, the information we learn from the space program is astonishing. The major advances in astronomy over the last 30 years have all come directly out of NASA. They're cataloging actual planets in other solar systems now, something that was impossible 30 years ago.
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