; (2) in subsection (a), by striking is an Under Secretary of the Air Force and inserting are two Under Secretaries of the Air Force ; and (3) by striking subsection (b) and inserting the following new subsections: (b) (1) One of the Under Secretaries shall be the Under Secretary of the Air Force. (2) The Under Secretary of the Air Force shall be the first assistant to the Secretary of the Air Force and shall assist the Secretary in the performance of the duties of the Secretary and shall act for, and exercise the powers of, the Secretary when the Secretary dies, resigns, or is otherwise unable to perform the functions and duties of the office. (c) (1) One of the Under Secretaries shall be the Under Secretary of the Air Force for Space, who shall also be known as the Under Secretary for Space. (2) The Under Secretary for Space shall be responsible for the overall supervision of space matters. (d) In addition to the duties and powers described in subsections (b) and (c), the Under Secretaries shall perform such duties and exercise such powers as the Secretary of the Air Force may prescribe. . (b) Conforming amendments (1) Table of sections The table of sections at the beginning of chapter 903 of such title is amended by striking the item relating to section 9015 and inserting the following new item: 9015. Under Secretaries of the Air Force. . (2) Secretary of the Air Force Section 9013(f) of such title is amended— (A) in the first sentence, by striking Under Secretary and inserting Under Secretaries ; and (B) in the second sentence, by striking the Under Secretary and inserting either Under Secretary . (3) Office of the Secretary of the Air Force Section 9014(b)(1) of such title is amended by striking Under Secretary and inserting Under Secretaries . (4) Successor to duties Section 9017 of such title is amended— (A) by redesignating paragraphs (2) through (4) as paragraphs (3) through (5), respectively