Howard Joel Wolowitz, M.Eng. (portrayed by Simon Helberg ; main: the Big Bang Theory seasons 1–12; guest: Young Sheldon season 5) is an aerospace engineer at Caltech's Department of Applied Physics who often hangs out at Leonard and Sheldon's apartment. Unlike Sheldon, Leonard, and Raj, Howard does not have a doctorate and often gets disparaged as a result, especially by Sheldon. He defends this by pointing out that he has a master's degree in Engineering from MIT and that the equipment he designs is launched into space, unlike the theoretical work of his friends. In the fifth-season finale, Howard goes to the International Space Station on Expedition 31.