Atrophy: is the degeneration of a normally developed organ or tissue. This may be due to lack of nourishment, lack of use, or aging. For example, muscle atrophy is reduction of muscle mass that results from lack of use of the muscles.
Centrifugal force: this force is included in the calculation of equilibria between forces in a rotating frame of reference. For example, for a rotating carrousel, rotating space station, rotating Earth. If all forces act on a body, in the rotating frame, the forces on a body of mass m are in equilibrium (demonstrated by the body staying at the same place).
Centripetal force: a special resulting force in which an object moves in a circular path. The velocity is constantly changing direction; therefore, the object is accelerating.
Fluid shift: shift of fluids from the lower to the upper body when it is exposed or is recovering from the effects of microgravity. This also occurs to a lesser extent during prolonged bed rest or when the lower body is exposed to negative pressure.
Free Fall: any object in descent under which the only force acting on it is gravity.
Keplerian Trajectory: an orbit that involves two spherical objects that are governed by gravitational forces only.
Microgravity: a condition of near-weightlessness that can be brought upon by free fall or unpowered spaceflight.
Orbit: trayectory of a body in space, generally under the influence of gravity.
Spatial Disorientation: the confusion of the senses when one doesn’t know which way is up or down or have any spatial frame of reference.
Systemic Circulation: a system that supplies nourishment to all of the tissues throughout the body, with the exception of the heart and lungs because they have their own systems.
Weightlessness: an environment where no force (such as weight) is sensed. This condition occurs in orbit or free fall, when gravity has produced its full acceleration and can produce no further effect.
Zero Gravity: a condition produced when the centrifugal force is in equilibrium with the gravitational force.
Compiled By: Shreya