Guest speakers are an exciting part of the USS curriculum. The United Space School has guest speakers from various parts of the space industry give lectures to the students about topics of interest to their Mars project. Lectures cover everything from nano-materials for spaceflight to space law and policy. Lecturers are volunteers, and provide the students with real experience from the field. The USS is also proud to include astronaut lectures in the curriculum, with a focus on long-duration spaceflight.

Because lecturers are usually visiting during their work day or have even traveled to give their presentations, lecture schedules are subject to change on the fly during Space School.