When you write some code and put it on a spacecraft headed into the far reaches of space, you need to it work, no matter what. Mistakes can mean loss of mission or even loss of life. In 2006, Gerard Holzmann of the NASA/JPL Laboratory for Reliable Software wrote a paper called The Power of 10: Rules for Developing Safety-Critical Code. The rules focus on testability, readability, and predictability:

NASA keeps the original film negatives from the Apollo program sealed in a frozen vault in Houston, TX and rarely grants access to them. As a result, nearly all of the photos we see of those historic missions were made decades ago or are copies of copies. Recently, the film was cleaned and digitally scanned at "an unprecedented resolution".

How Many Decimals of Pi Do We Really Need? 3.141592653589793. That’s it. For the whole visible universe!