((a)) Under regulations to be prescribed by the Secretary of the Army or the Secretary of the Air Force, as the case may be, each company, battery, squadron, and detachment of the National Guard, unless excused by the Secretary concerned, shall—

((1)) assemble for drill and instruction, including indoor target practice, at least 48 times each year; and

((2)) participate in training at encampments, maneuvers, outdoor target practice, or other exercises, at least 15 days each year.

((b)) An assembly for drill and instruction may consist of a single ordered formation of a company, battery, squadron, or detachment, or, when authorized by the Secretary concerned, a series of ordered formations of parts of those organizations. However, to have a series of formations credited as an assembly for drill and instruction, all parts of the unit must be included in the series within 90 consecutive days.

((c)) The total attendance at the series of formations constituting an assembly shall be counted as the attendance at that assembly for the required period. No member may be counted more than once or receive credit for more than one required period of attendance, regardless of the number of formations that he attends during the series constituting the assembly for the required period.

((d)) No organization may receive credit for an assembly for drill or indoor target practice unless—

((1)) the number of members present equals or exceeds the minimum number prescribed by the President;

((2)) the period of military duty or instruction for which a member is credited is at least one and one-half hours; and

((3)) the training is of the type prescribed by the Secretary concerned.

((e)) An appropriately rated member of the National Guard who performs an aerial flight under competent orders may receive credit for attending drill for the purposes of this section, if the flight prevented him from attending a regularly scheduled drill.

((f))

((1)) Under regulations to be prescribed by the Secretary of the Army or Secretary of the Air Force, as the case may be, a member of the National Guard may—

((A)) without his consent, but with the pay and allowances provided by law; or

((B)) with his consent, either with or without pay and allowances;

((2)) The training or duty ordered to be performed under paragraph (1) may include the following:

((A)) Support of operations or missions undertaken by the member’s unit at the request of the President or Secretary of Defense.

((B)) Support of training operations and training missions assigned in whole or in part to the National Guard by the Secretary concerned, but only to the extent that such training missions and training operations—

((i)) are performed in the United States or the Commonwealth of Puerto Rico or possessions of the United States; and

((ii)) are only to instruct active duty military, foreign military (under the same authorities and restrictions applicable to active duty troops), Department of Defense contractor personnel, or Department of Defense civilian employees.

((3)) Duty without pay shall be considered for all purposes as if it were duty with pay.