English: NASA Deputy Administrator Pam Melroy, second from left, Bob Cabana, NASA associate administrator, and NASA Administrator Bill Nelson, speak with the 2021 astronaut candidate class, Wednesday, Oct. 18, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Upon completion of two years of training they could be assigned to missions that involve performing research aboard the International Space Station, launching from American soil on spacecraft built by commercial companies, as well as deep space missions to destinations including the Moon on NASA’s Orion spacecraft and Space Launch System rocket. Photo Credit: (NASA/Joel Kowsky)