If you are in default on your military star card then the federal government may take your tax refund to pay your military star card.
You may be able to keep your tax refund in a Chapter 13 bankruptcy. If certain unexpected expenses emerge you may be able to request permission to keep your tax refund.
In most Chapter 13 bankruptcy cases you will not be able to keep your tax refund during the life of your plan. You will have to contribute your tax refund to your Chapter 13 plan.