Be careful about the creation of new tags without user demand.
We had a discussion about this a couple of years ago on Space Exploration:
How is our tagging situation? What can we do to improve it?
In the time since then, Space Exploration's tag count has continued to grow at a higher rate than comparable sites (albeit, slightly less than before), and not only that but Astronomy's tag count has started to grow at a similar rate. The other sites have remained relatively stable in their tag counts.
Why is this an issue? As described at the linked post, this creates a lot of poorly maintained tags. Space Exploration's singleton tags have dropped a bit, but they remain much higher than comparable sites. Astronomy's singleton tags have leapt up significantly in the past couple of years.
It's not out of control yet, but I'm just advising some extra caution here.