; (9) the technical and programmatic viability of any approaches for meeting space communications needs after all Tracking and Data Relay Satellite System third-generation communications satellites are operational; and (10) the extent to which the Administration has an established plan and measures for mitigating threats to electromagnetic spectrum use. (c) Transmittal The review in subsection (a) shall be transmitted to the Committee on Science, Space, and Technology of the House of Representatives and the Committee on Commerce, Science, and Transportation of the Senate not later than 1 year after the date of enactment of this Act. V Aeronautics 501. Research effort to advance sustainable aviation (a) In general The Administrator, in consultation with other relevant Federal agencies, industry, and academia, shall conduct research and development efforts that contribute to reducing the environmental impact of aviation, providing for a sustainable future for aviation, and improving the efficiency and performance of United States commercial aircraft. (b) Research Effort The research effort in subsection (a) shall include research, development, and demonstration projects on— (1) subsonic aircraft and engine design and technology; (2) sustainable aviation fuels; (3) electric and hybrid-electric propulsion; and (4) other efforts that contribute to a sustainable future for aviation. (c) Goals The goals of the initiative in subsection (b) shall be to reach— (1) two percent annual fuel efficiency improvement through 2050