NASA will be missing one of its top congressional supporters next year with the retirement of U.S. Sen. Kay Bailey Hutchison (R-Texas), and another, Sen. Bill Nelson (D-Fla.), is in a struggle to keep his seat, Space Policy Online reports.

Nelson, an avid supporter of NASA’s human spaceflight program who flew on the space shuttle in 1986, faces a tough race against the Republican challenger, U.S. Rep. Connie Mack IV, in the November election. Both men easily won their Florida primary races Aug. 14. Mack, the son of former U.S. Sen. Connie Mack III and husband of U.S. Rep. Mary Bono Mack (R-Calif.), represents a Gulf Coast district far from the Space Coast, and his stance on the space program is unclear.

Nelson and Hutchison helped forge a compromise with the White House on the 2010 NASA Authorization Act that backed development of the Space Launch System and Multi-Purpose Crew Vehicle to send humans beyond low Earth orbit along with reliance on commercial companies for transportation to and from the international space station.