Parents who are being deployed walk a fine line. They know they have to prepare their children for the challenges ahead, yet they don't want to worry them any more than necessary.
The best thing to do is to tell kids the truth — that Mom or Dad has to go away to do their job for our country — and to give explanations at a level they can understand. For example, young children have a limited concept of time, so their worries tend to focus on their daily routine (Who will take me to school in the morning? Who will tuck me in at night?). They need to know who'll be caring for them and keeping them safe in your absence.
Older kids, on the other hand, might have more concerns about the length of the separation and your well being. Reassure them as best you can that you are well trained to do your job and that every effort will be made to keep you safe.
Let children know it's OK to miss you — you'll be missing them, too. Talk about the ways you will keep your relationship strong — email, letters, photos, videos, even promising to think of each other at the same time every day. And finally, be sure to spend plenty of one-on-one time with your child in the days and weeks before your departure. These are the memories your child will hold on to until you return.