Child custody orders are very difficult when one party is in the military and on active service. Section 452.412 sets a number of limits on child custody modifications when a parent is in the military and deployed out of state:
A party’s absence, relocation […] shall not, by itself, be sufficient to justify a modification of a custody or visitation order if the reason for the absence, relocation […] is the party’s activation to military service and deployment out-of-state. Section 452.412.2.
As such, a Court cannot use military service as the sole basis for a modification; other facts evidencing a substantial change in circumstances must exist. And even when a Court does agree and modify a custody or visitation plan involving a military parent deployed out of state, the court order may last only:
during the time of such out-of-state military deployment of the party, including as part of an entry of decree of dissolution of marriage or legal separation, shall be temporary in nature and shall not exceed the length of time of such deployment. Section 452.412.2(2).
Obviously, this can be very frustrating because frequent changes in military status or deployment will necessitate further legal proceedings.