While I like the idea, I think you have the wrong five.
There's a subreddit called "Explain Like I'm Five" exactly for this kind of thing. My only concern is that it would be a meta tag, which are a no-no. Or is it? I mean, consider the similarities to this and the Beginner tag that used to be on Stack Overflow.
That being said, the target market of this ...
IMO - the "questionable" one is fine, but the other two should be untagged. I don't think a general "identify-this" tag is useful. That's kind of the point of most questions: to explain the phenomenon the person asked about.
I'm not sure that this is really necessary since "Lunar Module" is a pretty well understood name here, and any future spacecraft used for that purpose will probably have different names. If it does become an issue, we can always make a change at that point, but I don't think there's a need to do anything preemptively.
To me solar-power and the proposed tag photovoltaic-cell serve different purposes. solar-power is about energy source design, specifically designs made to draw power from the sun. photovoltaic-cell is about the use of a specific technology, regardless of the context of its use. I think solar-power should remain and not be made a synonym of anything. Likewise,...
I'm not necessarily opposed to my idea of a simple-english tag for this purpose, but there is a potential problem I see with this concept. This tag would open us up to having "simple" duplicates of every question.
Is there any reason to send space probes along the plane of our solar system instead of perpendicular to the plane of our solar ...
I disagree. Definition of regolith:
Regolith (/ˈrɛɡəlɪθ/)1 is a layer of loose, heterogeneous superficial deposits covering solid rock. It includes dust, soil, broken rock, and other related materials
(emphasis mine). Regolith is a superset of dust, so please don't treat them as synonyms.
I generally think of biology as the deliberate study of living things. It's a scientific field. life refers more to the incidental presence of living things, such as potential extra-terrestrial organisms, or the contamination from one world to another.
I don't think too strongly on the issue, and I could be convinced of a better distinction.
life should ...