NASA stands for the National Aeronautics and Space Administration, which is a government agency responsible for the civilian space program, as well as aeronautics and aerospace research. The term 'STOP!' in this context refers to the term 'ABORT, ' which is used to describe the process of ending a mission or procedure prematurely. The crossword solution for 'ABORT' in this context is five letters long and spells out the word 'ABORT.'