We appreciate Mr. Carbin's1 efforts in providing an insightful editorial commentary of our article entitled “Variations in Urinary Microbiota on a Short Duration Space Mission to the International Space Station.”2 As accurately stated, the main limitation of studies related to space travel is the sample size, demographics, and duration of these space travel expeditions. The inherent costs, complicated technology involved, limited purpose, as well as rigorous training and preparation related to space travel makes this an overall rare opportunity. In recent years, there has been increasing interest in space tourisms with more private companies offering opportunities for space travel without the need for undergoing scrupulous training as compared with professional astronauts. These expeditions range anywhere from suborbital flights to brief orbital flights to multiday journeys to the International Space Station. As the commercial space sector continues to grow, improved automation with the aid of artificial intelligence and reduced cost with reusable rockets may allow space travel to be conducted more routinely and efficiently. This may ultimately provide an increase in future study participants, subsequently expanding the overall sample size for any space-related studies conducted in orbit.
Chung et al. (Wed,) studied this question.