Yes. TNT appears to leave the base's metals dumped all over the
planet's surface. Seems to destroy everything else nicely though. I
managed to get rid of most of the Dur. and the Moly, just couldn't seem
to get rid of the Trit.
As for the timing, well, yes, you misjudged a bit

IIRC, you
invaded the same turn I TNT'd, and you did indeed destroy all the ships
you could see, and command codes are after combat, which leads to the
next question...
Perhaps you -- or someone else -- can settle something for me that does
not appear to be clearly (or correctly?) addressed anywhere, which is
whether non-Fed Lokis with skilled crew or HG can detect a perfectly
cloaked Bird-owned Resolute or Darkwing. From the anecdotal evidence
in our game (including one particular cloaked Resolute with a TNT
command), the answer appears to be no but I was wondering if you cared
to confirm.
-- Karnak Prime
>> Stay informed about: Visibility of Bird bases