When traveling in space, astronauts experience physiological changes normally associated with aging, such as bone loss, muscle deterioration and altered immune systems. When the astronauts return to Earth, the changes often reverse. To better understand the relevance of the astronauts’ experience to human health—both on the ground and beyond—NIH’s National Center for Advancing Translational Sciences (NCATS) partnered with the International Space Station U.S. National Laboratory (ISS National Lab) to send tissue chips, a research technology that reflects the human body, into space. The ISS National Lab and NASA partner to use the U.S. portion of the space station for research initiatives leveraging the unique microgravity environment in space.