In this podcast, NASA psychologist Al Holland discusses some of the the mental challenges astronauts might face during a mission to Mars.Podcast produced by David Levin. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by ExxonMobil, David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers.Find out how we might make it to Mars, and learn about the dangers we'd face along the way. Visit us at pbs.org/nova/sciencenow.