[zjp]

You know it never occurred to me I could look things up before. Everything I've ever known I learned orally. Even C. I remember sitting on pappy's lap, watching him wave his hand to draw out an asterisk in the air. "A pointer..."

Literary culture is so confusing.

Anyway, the editorial rule is to spell it out on the first use and then to abbreviate it:

The National Aeronautics and Space Administration (NASA) announced today... ...NASA says...

Many articles fail to do this and assume insider knowledge. It's all fine and good after you look it up or if you're an expert and familiar with the topic. Good for you. For everyone else, in other disciplines, or lay people, or for students, it's nice to extend the courtesy of spelling it out once.