I agree, acronyms and other abbreviations should be further explained at least once in posts they're used, regardless, if they're a question or an answer.
This has nothing to do with the depth of understanding of discussed topics by their readers. For example, IUA (The International Astronomical Union) abbreviation for the planet Mars is
Ma. It just so happens,
Ma is also an abbreviation for "millions of years ago" or Megaannum, and for Mach number, is a Vietnamese ethnic group, a language spoken in DRC Congo, and so on. And there are, of course, worse, even more ambiguous examples.
Additional bonus comes from SEO (Search Engine Optimization), making web search engines index our contents more precisely, and any hits we get due to more relevant indexing will bring us visitors that are more likely to stay, too.
Enforcing a single style might be a tough sell, though. To most of our contributors, I'd hope, Space Exploration isn't the primary target where they publish their work, and each would already have developped their own writing style, be it by mostly writing scientific journals, news articles, blog posts or other media where they might not be limited by text length and broadness of topics as much as they're dictated by our Q&A format. There's just too many possible annotation styles, and all serve the purpose of further explaining the meaning and/or avoiding ambiguity of used acronyms equally well.
Personally, I try to write contributions in ways I believe they will later be read by others, trying to preserve fluency. This might mean I'll even use different annotation styles throughout my posts (maybe also for variety, to avoid it being dull reading), but I try to explain the meaning of abbreviations at least once, and this might be done thusly;
Explain their meaning in written word, by writing it down "as read", not disturbing the reader's word flow too much, e.g.:
NASA, the National Aeronautics and Space Administration agency of the
United States government, will soon ...
Attach explanation in brackets, following the abbreviation used, e.g.:
NASA (the United States National Aeronautics and Space
Administration), will soon ...
Use marginal annotations by adding unique marks following used abbreviations, and explaining them in the footnote, captions to attached images, e.t.c., e.g.:
* United States National Aeronautics and Space
By using hyperlinks to simulate effects of semantic links similar to those used on our tags that have a tag wiki description (i.e. Wikipedia and a lot of other referenced web pages might use full names in their URLs, that display by simply hovering over a link in most browsers), or to also serve as an external reference, e.g.:
ESA will soon ...
By combining multiple of described options to annotate, further explain and remove possible ambiguity of used abbreviations, or by explaining their intended meaning later on, either quoted in short excerpts, by re-emphasising it with additional explanation, or sometimes - simply answering a question that is using them, e.g.:
Since ESA is the European Space Agency, ...
There are of course other methods, and each of us will have different style. I'm in no way trying to suggest how to achieve that, but I do agree that they are essential to better understanding of questions and their answers. Many different branches of science and technology will use possibly ambiguous abbreviations, if used in interdisciplinary topics stretching several of them, and their intended meaning might not be clear because of it.
TL;DR - If any such clarifications are required on already existing contributions, please go ahead and edit them, and they should be approved without further ado. Please do mind however, that questions and answers are automatically converted to community wiki, once they reach 10 revisions, as we don't want to rob their respective authors of reputation gained by upvoting and/or accepting them.