Research on astronaut health and model organisms have revealed six features of spaceflight biology that guide our current understanding of fundamental molecular changes that occur during space travel. The features include oxidative stress, DNA damage, mitochondrial dysregulation, epigenetic changes (including gene regulation), telomere length alterations, and microbiome shifts. Here we review the known hazards of human spaceflight, how spaceflight affects living systems through these six fundamental features, and the associated health risks of space exploration. We also discuss the essential issues related to the health and safety of astronauts involved in future missions, especially planned long-duration and Martian missions.

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FT decreased intraoperative times, intraoperative red blood cell and cryoprecipitate transfusions, the need for prolonged mechanical ventilator support, renal failure and hospital length of stay. Using FT in MIAVR will allow for more reproducible, widespread adoption of minimally invasive approaches for aortic valve replacement.

Objective Valve-sparing aortic root replacement (David procedure) is the technique of choice in appropriately selected patients with aortic root aneurysms. These procedures are seldom performed in a minimally invasive fashion. We describe our systematic approach to the David procedure using an upper hemisternotomy (UHS). Methods: Our method involves a J-type UHS exiting the right third or fourth intercostal space. Ascending aortic and femoral venous cannulation are performed using the Seldinger technique under transesophageal echocardiographic guidance. Between August 2005 and August 2014, 27 patients underwent an isolated elective David procedure using a full sternotomy (FS). Sixteen underwent an isolated elective UHS David procedure from May 2015 to February 2019. Perioperative safety outcomes were compared between the 2 cohorts. Results: The UHS and FS David cohorts were primarily male (87.5% and 85.2%, respectively) and 51 and 50 years old on average, respectively. Custodiol-histidine-tryptophan-ketoglutarate cardioplegia (93.8% vs 37.0%, P < 0.001) and Cor-Knot (100% vs 0%, P < 0.001) were used significantly more in the UHS David cohort. There were no significant differences in cardiopulmonary bypass (200 [183–208] vs 212 [183–223] min, P = 0.309) and aortic cross-clamp (169 [155–179] vs 188 [155–199] min, P = 0.128) times in the UHS and FS cohorts. There were no instances of hospital or 30-day mortality in either cohort. Intensive care unit and hospital stays were comparable between the 2 cohorts. Conclusions: The David procedure via UHS is a safe and reproducible technique for aortic root replacement.