This question has been appearing in several places recently! I answered a version of it
here last week, although I will mention that this part hides something of note:
I know that we blowd him up as the first titan to be destroyed.
The reasons for having some remaining Control systems now is related very strongly to being the first Titan destroyed:
- We cleared all its systems last November 3309—before Titans could be destroyed at all—and it started capturing them again after they completed Recovery.
- Doing that required an absolutely massive effort and expended all its Spire sites, without which we could not do it again.
- Thus, we had to destroy Titan Taranis first in February 3310 because it was recapturing systems we could no longer win back.
For the three months from then until Titan Hadad exploded in May 3310 as the fourth Titan destroyed, there was simply nothing to be done about the remaining Taranis systems. They were no longer attacking anything at least, and nor were they reinforcing each week, but still they were simply too prohibitively strong to clear away.
That changed at the end of May 3310 with the
Thargoid War overhaul, which you can see has
System difficulty is now linear with respect to distance from a Titan, making capture possible again. Titan Taranis exploded while it had seven Control systems, then its remaining Alerts and Invasions completed to give it a few more after it was already gone, but a few Commanders have since returned and reduced that to four.