; (B) the estimated number of officers needed to fill vacancies in those positions during the period in which it is anticipated that officers selected for promotion will be promoted; and (C) the number of officers in a space force active status authorized by the Secretary of the Air Force to serve both on sustained duty and not on sustained duty in the grade and competitive category under consideration. (b) Promotion to brigadier general and major general (1) Determination of maximum numbers Before convening a selection board under section 20211 of this title to consider officers for recommendation for promotion to the grade of brigadier general or major general, the Secretary of the Air Force shall determine the maximum number of officers serving in a space force active status on sustained duty, and the maximum number of officers serving in a space force active status not on sustained duty, that the board may recommend for promotion. (2) Determinations In order to make the determinations under paragraph (1), the Secretary shall determine— (A) the number of positions needed to accomplish mission objectives which require officers serving in a space force active status on sustained duty, and in a space force active status not on sustained duty, in the grade to which the board will recommend officers for promotion