in-space propulsion system to support crewed missions to Mars. (b) Plan The Administrator shall develop a plan, including a cost estimate, to achieve an in-space flight test of a nuclear thermal propulsion system within 10 years of the enactment of this Act. (c) Transmittal The Administrator shall transmit the plan 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 12 months after the date of enactment of this Act. 603. Nuclear surface power (a) Sense of congress Developing lightweight fission reactors systems is critical for generating sufficient power to run systems that enable long-term presence, robotic or human, in space. It is the sense of Congress that NASA should continue developing kilopower technology. (b) Program The Administrator shall establish a program for research, testing, and development of a space surface power reactor design. (c) Plan NASA shall develop a plan and timeline for a kilopower program taking into consideration mission needs and shall include opportunities for participation by United States commercial entities. (d) Transmittal The Administrator shall transmit plan 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 12 months after the date of enactment of this Act. 604. Review of flight opportunities program (a) Review The Comptroller General shall carry out a review of the Flight Opportunities Program to assess— (1) the goals and objectives of the program, and the basis for those goals and objectives