From a post to Baen's Bar Honorverse dated June 11, 2008:

Do you plan ahead for which characters die?

    I know from the moment that I introduce them that some characters are going to die. Paul Tankersley was a case in point in the Honorverse, as was the original Sean MacIntyre in Mutineers' Moon, or Raoul Courvosier. Others end up dying (or living, against original plans) because of something the story demands. And some of them end up dying because I write military fiction and in military fiction, good people die as well as bad people. Military fiction in which only bad people -- the ones the readers want to die -- die and the heroes don't suffer agonizing personal losses isn't military fiction: it's military pornography. Someone who write military fiction has a responsibility to show the human cost, particular because so few of his readers may have any personal experience with that cost. In answer to your specific questions, I knew that one of the middies was going to be killed in the confrontation with the Jessyk Combine ship. The fact that Ragnhild wound up as Terekhov's personal shuttle pilot made it her. And in AAC, it was actually Honor who was supposed to die and McKeon who was supposed to arrive too late to save her. Due to some things which happened when Eric and I started collaborating, elements I had planned for a post-Honor Honorverse (if that makes sense) got pulled forward considerably in time. As a result, there wasn't time for me to have Honor's child mature to a point of dealing with the new generation of problems. I won't pretend that I was heartbroken to not killer her after all, since it had never been something I'd looked forward to, but that was the original game plan.