1969 in spaceflight with Apollo 12 also landing on the surface. The success of the Apollo program was a testament to the efforts of over 500,000 American engineers, scientists and technicians. In 1969, the Soviet Union's space program had success with the docking of two manned spacecraft as well as the success of their Venus and Lunar probes. The Soviets, however, suffered severe blows to their manned Lunar aspirations when their N1 rocket failed twice during two 1969 launches. <br> 1969 in spaceflight 1969 saw humanity step onto another world for the first time. On 21 July 1969, the Apollo 11 Lunar Module,
Effect of spaceflight on the human body Effect of spaceflight 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 (spaceflight osteopenia). Other significant effects include a slowing of cardiovascular system functions, decreased production of red blood cells, balance 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 Earth and developing