37 U.S.C. § 305

1. (a)A member of a uniformed service who is entitled to basic pay may be paid special pay under this section while the member is performing duty that is designated by the Secretary of Defense as hardship duty.
2. (b)Special pay payable under this section may be paid on a monthly basis or in a lump sum.
3. (c)
   1. (1)The monthly rate of special pay payable to a member under this section may not exceed $1,500.
   2. (2)The amount of the lump sum payment of special pay payable to a member under this section may not exceed the product of—
      1. (A)the maximum monthly rate in effect under paragraph (1) at the time the member qualifies for payment of special pay under this section; and
      2. (B)the number of months during which the member will be performing the designated hardship duty.
4. (d)Special pay paid to a member under this section is in addition to any other pay and allowances to which the member is entitled.
5. (e)A member who is paid special pay in a lump sum under this section, but who fails to perform the designated hardship duty during the months included in the calculation of the amount of the lump sum under subsection (c)(2), shall be subject to the repayment provisions of section 303a(e) of this title.
6. (f)The Secretary of Defense shall prescribe regulations for the payment of hardship duty pay under this section, including the specific monthly rates at which the special pay will be available.