I'm playing around with some machine learning software I've written. It would be theoretically possible to code this to answer real word questions (like those asked on this site). Of course any answers are only as complete as the sources the answer is constructed from. Are there any plain text document repositories for the field of space exploration?
Yes. In the documents collection of each bundle you can find science articles. It is up to the data provider to include these.
8A.2.2 Document Products The range of relevant documents will depend on the type(s) of data and the scope of the associated collections and bundle. In general, completeness of information is the goal. For a typical planetary spacecraft mission, documents could include: • Mission Plan • Instrument papers • Instrument user guides • Calibration reports • Science articles • Archive content, format, and organization, e.g. Software Interface Specifications (SISs) • Software user manuals