Here's how you know that Jessica Chastain's role in The Martian may inspire girls to want to become astronauts: she inspired the astronaut who helped her prepare. In an exclusive clip, astronaut Tracy Caldwell Dyson interviews Chastain about her role as the disco-loving Commander Lewis, who leads her team on a mission to retrieve fellow crew member Matt Damon's Mark Watney from Mars. Watney is, unfortunately, left behind after the rest of the crew assumed he died when they were evacuating during a storm. When Dyson asks Chastain about what she hopes people get from watching her play Commander Lewis, Chastain explains, "You know what would be great? If there is a little girl who watches the film and then says I want to do that." Apparently, watching the trailer brought out the "little girl" in Dyson. The astronaut tells Chastain she told her husband, "she makes me want to be an astronaut." When Chastain says that Dyson's "already doing it," Dyson responds, "you made me want to keep doing it." Dyson helped Chastain with her portrayal. Chastain spent a day at Johnson Space Center with Dyson, and also visited NASA's Jet Propulsion Laboratory. The Martian, which comes out Friday, is especially timely given the recent discovery of water on Mars. (Something that apparently director Ridley Scott was aware of before the rest of us were.) It also happens to be a very good critical examination about the necessity of space travel and human ingenuity.