This episode continues our series of episodes on space biology and #SpaceOmics with Dr. Tejaswini Mishra. Dr. Mishra introduces The NASA Twins Study, a cornerstone scientific work where two twin astronauts were monitored, with one twin traveling to space, and one staying on earth. Dr. Mishra explains the importance of studying long term spaceflight missions, how The NASA Twins Study was set up in a particularly great way to study spaceflight impact, the many different types of data collected and analyzed, and some of the results found by the study. During the episode, Dr. Mishra explains many of the types of data collected such as microbiome and telomere data. After covering the types of data, we explore some of the main results such as the first ever test of a vaccination in space. Dr. Mishra then explains more in depth on changes seen during spaceflight such as telomere length, gene expression, DNA damage, cognitive function, and more. We discuss how concerning the various changes that occur in space could be for astronauts, such as becoming hypoxic. Dr. Mishra also explains pointers to the kinds of things we should focus on when we go deeper into space for understanding the impact on the human body. Finally, we summarize the main messages of the paper and hear Dr. Mishra’s thoughts on the future of space research.  The NASA Twins Study can be found at: https://science.sciencemag.org/content/364/6436/eaau8650