 Effect of space flight on the human body, venturing into the environment of space can have negative effects on the human body. Significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton space flight osteopenia. Other significant effects include the slowing of cardiovascular system functions, decreased production of red blood cells, balanced disorders, eyesight disorders and a weakening of the immune system. Additional symptoms include fluid redistribution causing the moon face appearance typical in pictures of astronauts experiencing weightlessness loss of body mass, nasal congestion, sleep disturbance, and excess flatulence. The engineering problems associated with leaving birth and developing space propulsion systems have been examined for over a century, and the ends of man hours of research have been spent on them. In recent years there it has been an increase in research on the issue of how humans can survive and work in space for extended and possibly indefinite periods of time. This question requires input from the physical and biological sciences and has now become the greatest challenge other than funding facing human space exploration. A fundamental step in overcoming this challenge is trying to understand the effects and impact of long-term space travel on the human body. In October 2015, the NASA Office of Inspector General issued Health Hazards Report related to space exploration, including a human mission to Mars.