To pursue a career in research related to medicine and space, individuals can explore fields like aerospace medicine and medical physics, which integrate these interests. Astronauts are specifically defined as those who participate in space missions, while roles such as astrophysicists focus on space science without necessarily engaging in missions. Combining an MD/PhD with a PhD in astrophysics is challenging due to the differing nature of the fields, but some programs may allow for interdisciplinary studies. Biographies of current astronauts reveal that many have diverse backgrounds, including medicine, which can provide insight into potential career paths. Research opportunities exist for biologists studying the effects of zero gravity on human health, though these positions are competitive.