Astronomy And Space Science: Your Bones in Space Hypogravitational Osteoporosis: A review of literature. By Lambert Titus Parker. May 19 1987. (GEnie Spaceport) Osteoporosis: a condition characterized by an absolute decrease in the amount of bone present to a level below which it is capable of maintaining the structural integrity of the skeleton. To state the obvious, Human beings have evolved under Earth's gravity "1G". Our musculoskeleton system have developed to help us navigate in this gravitational field, endowed with ability to adapt as needed under various stress, strains and available energy re