that will give him his ride. and in orbit a year of his life will be in the real version, not this model of the space station. >> there's not a lot of room in here. pretty comfortable for space bedroom. >> we need to figure out how people are going to live in space for really long periods of time. especially if we want to send someone to mars. or maybe want to send people to -- they want to one day build a base on the moon. >> reporter: to better figure that out while scott is in space, his twin brother will stay on earth, the brothers perfect subjects to study since they share the unique genetic code. >> how important is it to have a twin mark, on the ground as i baseline as you watch scott for a year in space. >> we can look at how the genes and proteins made from them change as a result of this unique environment. >> reporter: for scientists like nasa's doctor dr. steven gilmore this would provide a gold mine of data. the first step in ambitious plans for space. nasa will use the data to figure