ABORT - an unscheduled interruption of a launch or a flight, enabling the safe release of an astronaut.
ABSOLUTE HUMIDITY - the amount of water vapor present in a unit quantity of a gas, generally expressed as a mass of water vapor per unit volume of gas plus water vapor, e.g., as grains per cubic foot.
ACCELERATION - the rate of change of velocity, expressed in feet (or centimeters) per second. See also PHYSIOLOGICAL ACCELERATION.
ACCEPTOR- changes produced by the organism's own behavior.
ACCLIMATIZATION - the habituation of an organism to a changed or different environmental condition.
ACOUSTICS - the science of sounds. The term includes propagation and conduction of all kinds of material vibration their generation, perception, measurement reproduction.
ACCUMSTOMIZATION - the process of learning the techniques of living with a minimum of discomfort in an extreme or new environment. See also ACCLIMATIZATION and ADAPTATION.
ADAPTATION - the response and adjustment of an organism to its total environment, or the process by which it becomes fit. See also ACCUMSTOMIZATION.
AEROEMBOLISM - the formation or liberation of gases in the blood vessels of the body brought on by a too rapid change from a high, or relatively high, atmospheric pressure to a lower one. See COMPRESSED AIR ILLNESS.
AERO-OTITIS MEDIA - an inflammatory reaction of the middle ear resulting from a difference m pressure between the gas in the middle ear and the surrounding atmosphere. Also called otitic barotrauma. See also OTITIS MEDIA.
AEROSINUSITIS - an inflammatory reaction of one or more of the accessory nasal sinuses, resulting from a difference in pressure between the gas in the sinus and the surrounding atmosphere Also called sinus barotrauma.
AEROSPACE MEDICINE - a speciality of medicine dealing with the treatment or prevention of unfavorable psycho-physiological functioning, resulting from flight or its related conditions.
AIR CONDITIONING - the process of cooling, cleaning, humidifying, or dehumidifying air in a room, hall, building etc.
AIR SICKNESS - a condition of sickness frequently resulting from flight or acceleration.
ALTITUDE SICKNESS - in general, any sickness brought on by exposure to reduced oxygen tension resulting from reduction of barometric pressure.
ALVEOLAR OXYGEN PRESSURE - the oxygen pressure in the alveoli. The value is about 105 millimeters of mercury.
ALVEOLI - terminal air sacs deep within the lungs.
ANOXEMIA - See HYPOXEMlA.
ANOXIA - condition resulting from lack of sufficient oxygen for normal metabolic functions.
ANTHROPOMETRY - science of measurement of the human body itself, its parts and their relationships.
ANTIBIOTICS - chemical substances produced by microorganisms that alter the normal processes of other forms of life; may exhibit either cidal static or toxic- effects.
ANTI-G SUIT - Sec G SUIT.
ASTRONAUT - person who rides in a space vehicle; test pilot or scientist. See COSMONAUT.
ASTRONAUTICS - the art, skill, or activity of operating spacecraft; in a broader sense, the science of spacefIight.
ATMOSPHERE - envelope of air surrounding the Earth; also the body of gases surrounding or comprising any planet or other celestial body (compare biosphere, geosphere, hydrosphere, lithosohere).
BAILOUT BOTTLE - personal supply of oxygen usually contained in a cylinder under pressure, utilized when the individual has left the central oxygen system, as in a parachute jump.
BAROTRAUMA - injury of a part or organ as a result of changes in barometric pressure (used as otitic barotrauma). See AERO-OTITIS MEDIA and AEROSINUSITUS.
BEHAVIOR - the way in which an organism, organ, body, or substance acts in an environment or responds to excitation, as the behavior of steel under stress, or the behavior of an animal in a test.
BENDS - popular term for COMPRESSED AIR ILLNESS.
BIOASTRONAUTICS - study of biological, behavioral, and medical problems pertaining to astronautics. This includes systems functioning in the environments expected to be found in space, vehicles designed to travel in space, and the conditions on celestial bodies other than Earth.
BIOCHEMISTRY - chemistry dealing with the chemical processes and compounds of living organisms.
BlODYNAMlCS - study of the effects of dynamic processes (motion, acceleration, weightlessness etc.) on organisms.
BIOENGlNEERlNG - the art or science of designing the function or behavior of building, or equipping mechanical devices or artificial environments to the anthropometric, physiological, or psychological requirements of the organisms that will use them. The application of engineering techniques to biological problems.
BIOINSTRUMENTATlON - use of instruments for the purpose of detecting, measuring, recording' telemetering, processing, or analyzing different biological values or quantities as encountered in spaceflight.
BIOLOGICAL RHYTHM - change in a variable biological process as influenced by environmental conditions. See also CIRCADIAN RHYTHM and DIURNAL RHYTHM.
BIOLOGY - the science of life and the living.
BIOMETRY - the application of mathematical and statistical principles to the biological sciences
BIONICS - the study of systems, particularly electronic systems, which function after the manner of, or in a manner characteristic of, or resembling, living systems.
BIOPAK - container for housing a living organism in a habitable environment and for recording biological functions during spaceflight.
BIOPHYSICS - the physics of vital processes.
BIOSATELLITE - an artificial satellite specifically designed to contain and support humans, animals, or other living material in a reasonably normal manner for an adequate period of time and which, particularly for humans and animals, possesses the proper means for safe return to the Earth. See ECOLOGICAL SYSTEM.
BIOSENSOR - a sensor comprising a living system used to provide information about interaction of physical conditions and biological response in a particular environment.
BIOSPHERE - transition zone between Earth and the atmosphere within which most form of terrestrial life are commonly found; the outer portion of the geosphere, the inner or lower portion of the atmosphere, and the hydrosphere.
BIOTELEMETRY - the remote measuring and evaluation of life functions, as in spacecraft and artificial satellites.
BIOTRON - test chamber used for biological research within which the environmental conditions can be completely controlled, thus allowing observations of the effect of variations m environment on living organisms or providing particular environments whenever needed.
BRADYCARDIA - abnormal slowness of the heartbeat.
CARDIOVASCULAR - pertaining to the heart and blood vessels.
CHEMICAL STERILIZATION - complete destruction of microorganisms by chemical substances.
CHLOROPLAST - a plastic containing chlorophyll, with or without other pigments, embedded singly or in considerable numbers in the cytoplasm of a plant cell.
CHOKES - pain and irritation in chest and difficulty in breathing, due to release of gas bubbles in the pulmonary circulation as a result of reduced ambient pressure.
CHROMOSOMES - basophilic granules consisting of deoxyribonucleic acid containing the hereditary factors. They are usually constant in number for a biological species. The chromatin of the cell nucleus resolves into the chromosome prior to mitotic division of the cell.
CIRCADIAN RHYTHM - a regular change in physiological function occurring in approximately 24-hour cycles, or other well-defined time intervals.
CLEAN ROOM - an area where viable and nonviable particles are controlled according to established standards.
CLOSED ECOLOGICAL SYSTEM - system that provides for the maintenance of life in an isolated living chamber through complete reutilization of the material available in particular, by means of a cycle wherein exhaled carbon dioxide, urine and other waste matter are converted chemically or by photosynthesis into oxygen, water, and food.
CLOSED RESPIRATORY GAS SYSTEM - completely self-contained system within a sealed cabin, capsule, or spacecraft that will provide adequate oxygen for breathing, maintain adequate cabin pressure, and absorb the exhaled carbon dioxide and water vapor.
COMPONENTS - an integral part of a complete unit that is essential to perform a particular function required of the unit.
COMPRESSED AIR ILLNESS - a disease or condition characterized principally by neuralgic pains, cramps, and swelling, and which includes collapse and sometimes results in death. This condition is caused by the formation of the gas bubbles (mostly nitrogen) in the body fluids, the tissues, and in the circulating blood. It is the result of lowered gas tension associated with the relatively rapid reduction of ambient pressure, i. e. a too rapid change from a high or relatively high atmospheric pressure to a lower one.
CONDITIONED REFLEX - a reflex not normally present that has been developed by regular association of some physiological function with an unrelated outside event or stimulus.
CONTAMINANT - a viable or nonviable particle, the presence of which may or may not interfere with the results of a planned experimental program.
CONTROL - to regulate, check, or keep within limits.
COORDINATION - to bring into a common action, movement, or condition; to act together in a smooth, concerted way.
CORIOLIS EFFECTS - physiological effects (nausea, vertigo, dizziness, etc ) felt by a person moving radially in a rotating system, as a rotating space station.
CORIOLIS FORCE - a deflecting force acting on a body in motion (as an airplane or projectile) due to the Earth's rotation. Any object moving above the Earth with constant space velocity is deflected relative to the surface of the rotating Earth. Deflection is to the right in the northern hemisphere and to the left in the southern hemisphere.
COSMIC RADIATION - highly penetrating radiation from extraterrestrial sources reaching the entire surface of the Earth The hard (primary) component consists of high-energy particles, mainly mesons, a small number of protons, and a few nuclei of heavier atoms like carbon, nitrogen, oxygen, and iron The soft (secondary) component, largely formed as the result of interaction with the atmosphere, is made up of about equal pro portions of positrons, negative electrons (negatrons), and photons with energy less than 200 MeV.
CREPUSCULAR - pertaining to twilight as opposed to day or night. Animals, birds, and insects that are active at dawn or dusk are said to be crepuscular.
CULTURE - the propagation of microorganisms or of living tissue cells in special media conducive to their growth; the process by which microorganisms are grown as a means of isolation and identification; or the growth of microorganisms.
CYBERNETICS - comparative study of the automatic control system formed by the nervous system and brain, and by mechanical-electrical communication systems; the science of control mechanisms and of the transmission and processing of information that they entail; mathematical modeling, biostatistics, biophysics, computer simulation of physiological processes and computerization of data reduction, man-machine interrelationships. See also MAN-MACHINE INTEGRATION.
DECELERATION - rate of diminution in the speed of a vehicle or moving part; measured in feet per second per second.
DECOMPRESSION - systematic reduction of atmospheric pressure; particularly, various techniques for preventing CAISSON DISEASE or the CHOKES.
DECONTAMINATION- process of removing chemical, biological, or radiobiological contamination from, or neutralizing it on, a person, item, or area.
DEHYDRATION - removal of water from the body or a tissue; or the condition which results from undue loss of water.
DEMAND OXYGEN SYSTEM - see DEMAND SYSTEM.
DEMAND SYSTEM - an oxygen system in which oxygen flows to the user during inspiration.
DENITROGENATlON - removal of nitrogen dissolved in the blood and body tissues, usually by breathing pure oxygen for an extended period of time, in order to prevent aeroembolism at high altitudes
DESlCCATlON - dehydration; the removal of water.
DlASTOLlC BLOOD PRESSURE - pressure exerted by the blood during periods between cardiac contraction.
DISORIENTATlON - loss of proper bearings or a state of mental confusion, especially as to time, place, or identity.
DlURESIS - increased secretion of urine.
DIURNAL - related to daytime. Animals active mainly during daylight hours are said to be diurnal; the opposite of nocturnal.
DIURNAL RHYTHM - regular change in physiological function occurring in approximately 24-hour cycles.
DOSE - also referred to as dosage. The accumulated or total quantity of radiation. According to current usage, the radiation delivered to a specific area of the body or to the whole body. Units used in specifying the dose are roentgens for x rays or gamma rays, and reps or rems for beta rays.
DOSIMETRY - accurate and systematic determination of the amount given up by ionizing, radiation in tissues and other substances. See also PERMISSIBLE DOSE and DOSE.
DRUG - substance used as a medicine.
DRYHEAT STERlLIZATION - destruction of all living forms through use of high temperature applied in the absence of appreciable moisture.
DYNAMIC STEREOTYPE - system of conditioned reflexes reinforced numerous time the same sequence or combination so that they come to be performed smoothly.
DYSBARISM - pathological condition of the body resulting from the existence of pressure differential between the total ambient pressure and the total pressure of dissolved and tree gases within the body tissues, fluids and cavities. See also COMPRESSED AIR ILLNESS.
DYSPNEA - difficult or labored breathing.
EBULLISM - formation of bubbles, with particular reference to water vapor bubbles in biological fluids caused by reduction of ambient pressure, the boiling of body fluids.
ECOLOGY - study of the environmental relation and interaction of organisms, both flora and fauna.
ENDOCENOUS RHYTHM - rhythm generated from within the animal (i.e., an internally driven rhythm).
ENERGY BALANCE - conserved quantity involving the maximum amount of work that a system does in coming to a state of equilibrium.
ENVIRONMENT - external condition, or the sum of such conditions, in which a piece of equipment, a living organism, or a system operates.
ENZYME - an organic compound, frequently a protein capable of accelerating or producing by catalytic action some change in its substrate for which it is often specific.
ESCAPE - safe ejection of an astronaut.
EXPIRATORY RESERVE - volume of air that can be expelled from the lungs after a normal expiration.
EXPOSURE SUIT - suit designed to protect a person from harmful effects of extreme environment, such as cold or heat.
EXTRAPOLATION REFLEXES - perception of a changing situation whereby an organism is able to foresee further development of an ongoing process and behave accordingly.
EXTRATERRESTRIAL LIFE - life forms evolved and existing outside the space vehicle.
EXTRAVEHICULAR ACTIVITY (EVA) - activity of an astronaut in space outside the space vehicle.
EXOBIOLOGY - branch of biology that deals with the search for life beyond the regions of the Earth.
FATIGUE -a state of increased discomfort and decreased efficiency resulting from prolonged or excessive exertion, with resulting loss of powers or capacity to respond to stimulation.
FEEL - the sensation or impression that a pilot has or receives as to his or the aircraft's altitude, orientation, speed, direction of movement, or acceleration, or proximity to nearby objects, or, as most often used, as to the aircraft's stability and responsiveness to control.
FILTER - a medium such as spun glass, paper, or wire mesh used to remove matter from a volume of air or liquid.
FIRST SIGNAL SYSTEM - system of conditioned reflexes to nonlanguage stimuli; includes both somatic and visceral reflexes; is common to animals and man; in man it is very intimately related to the second signal system.
FLOTATION GEAR - gear or apparatus, such as commonly inflatable bags, vests, and rafts, carried aboard a vehicle to support the vehicle or persons downed in water.
FRUSTRATION THRESHOLD - level of emotional trauma at which an individual feels or shows frustration over inability to achieve an objective.
FULL PRESSURE SUIT - suit which completely encloses the body and in which a gas pressure sufficiently above ambient pressure for maintenance of normal function may he sustained.
FUNCTIONAL RESERVES - ability of the body to accomplish additional muscular or other activity and useful work beyond the normal level of activity of an individual.
GAMMA RAY - a quantum of electromagnetic radiation emitted by a radioactive nucleus, each such photon being emitted as a result of a quantum transition between two energy levels of the nucleus.
GAS EXCHANGER - biological system used to provide oxygen and remove carbon dioxide as a means of life support during spaceflight.
G-FORCE - inertial force usually expressed in multiples of Earth gravity.
GNOTOBIOTICS - aspect of biology concerned with animals whose microbial populations are totally known and rigidly controlled.
GRAVIRECEPTORS - highly specialized nerve endings and receptor organs located in skeletal muscles, tendons, joints, and the inner ear, which furnish information to the brain about body position, equilibrium, and the direction of gravitational forces.
GRAVITATIONAL BlOLOGY - study of the force of gravitation and its effect on life forms.
GRAVITY - a property of matter which gives rise to an attractive force between masses. See SUBGRAVITY.
G-SUIT - suit that exerts pressure on the abdomen and lower parts of the body to prevent or retard the collection of blood below the chest under positive acceleration. See PRESSURIZED SUIT.
G-TOLERANCE - a limiting value in a person or other animal, or in a piece of equipment, to an acceleration.
HEAT TOLERANCE - a limit to withstand higher than normal temperatures without loss of efficiency or impairment of function.
HIGHER NERVOUS ACTIVITY - activity of the cortex and higher parts of the subcortex, i. e, activity which maintains the complex relations of the whole organism to the external world; may rightly be called (in place of the earlier term psychological") higher nervous activity.
HIBERNATION - the dormant, torpid, resting, reduced metabolic state in which certain animals pass the winter.
HUMAN ENGINEERING - science of designing, building, or equipping mechanical devices or artificial environments to the anthropometric, physiological, or psychological requirements of the people who will use them.
HUMAN FACTOR - study of psychological and physiological variables that affect man's performance in an operational system.
HYDROSTATIC EQUILIBRIUM - state of a fluid whose surfaces of constant pressure and constant mass or density coincide and are homeostatic throughout.
HYPEROXIA - condition in which the total oxygen content of the body is increased above that normally existing at sea level.
HYPERVENTILATION - overbreathing; a respiratory-minute volume, or pulmonary ventilation, that is greater than normal.
HYPERVENTILATION SYNDROME - syndrome of blurring of vision, sensation, tingling of the extremities, faintness, and dizziness, which may progress to unconsciousness and convulsions, caused by reduction of the normal carbon dioxide tension of the human body, due to increased pulmonary ventilation.
HYPOBARIC - pertaining to low atmospheric pressure, particularly the low atmospheric pressure of high altitudes.
HYPOBARISM - disturbances resulting from a decrease of ambient pressure to less than that within the body fluids, tissues, and cavities.
HYPOCAPNIA - deficiency of carbon dioxide in the blood and body tissues, which may result in dizziness, confusion, and muscular cramps.
HYPODYNAMIA - diminished power; a reduction of normal or vital powers.
HYPOVENTILATION - a respiratory-minute volume or pulmonary ventilation that is less than normal.
HYPOXEMIA - condition or reduction of the normal oxygen tension in the blood.
HYPOXIA - deficiency of oxygen; any state wherein a physiologically inadequate amount of oxygen is available to, or utilized by, tissue without respect to cause or degree.
IMMOBILIZATION - usually considered to be physical or mechanical, but could be biochemical. See also RESTRAINT SYSTEM.
INSTABILITY - condition of a body if, when displaced from a state of equilibrium it continues, or tends to continue, to depart from the original condition. Compare stability.
INTERMITTENT PRESSURE BREATHING - pressure breathing in which different pressures are used at different points in the respiratory cycle, usually with a high pressure during inspiration and lower pressure during expiration.
INTEROCEPTIVE-EXTEROCEPTIVE AFFERENTATION - refers to neural impulses reaching the cortex from the sensory receptors of internal organs (interoceptive) or from the external environment (exteroceptive).
IONIZATION - process by which neutral atoms or groups of atoms become electrically charged, either positively or negatively, by the loss or gain of electrons; or the state of a substance whose atoms or groups of atoms have become thus charged.
IONIZING RADIATIONS - any particulate or electromagnetic radiation capable of producing ions, directly or indirectly, in its passage through matter. Alpha and beta particles produce ion pairs directly, while gamma rays and x-rays liberate electrons as they traverse matter, which in turn produce ionization in their paths.
IRRADIATION - exposure to radiation. One speaks of radiation therapy, but of irradiation of the patient. The exposure of material to x-ray, gamma-ray, or slow neutron radiation The exposure of material in a nuclear reactor. Bombardment of material with particle radiation.
ISOLATION - use of culture medium or other appropriate environmental conditions for the purpose of further study in medicine, to separate from other persons, materials, or objects.
LABYRINTHINE - referring to the labyrinth of the inner ear, which acts as an acceleration sensor.
LAG - delay between change of conditions and the indication of the change on an instrument Delay in human reaction. The amount one cyclic motion is behind another, expressed m degrees. The opposite is "lead."
LAP BELT - safety belt that fastens across the lap. This is the usual kind of safety belt. Also called a seat belt.
LEANS - illusion of a craft being tilted, with corresponding leaning of the crew in the opposite direction, caused by a false labyrinthine reaction uncorrected by visual cues.
LENS - medium-crystalline lens of the eye.
LIFE SCIENCES - field of scientific disciplines encompassing biology, physiology psychology, medicine, sociology, and other related areas.
LIFE SUPPORT SYSTEM - system of instrumentation used in a spacecraft to facilitate the maintenance of normal life processes in living organisms. See also NITROGEN CYCLE.
MAGNETIC FIELD - region in the neighborhood of a permanent magnet or a current carrying conductor in which magnetic forces can be detected.
MAN-MACHINE SYSTEM - system in which the functions of the man and the machine are interrelated and necessary for the operation of the system.
MAN-MACHINE INTEGRATION - matching of the characteristics and capabilities of man and machine to obtain optimum conditions and maximum efficiency of the combined system.
MANNED - refers to a vehicle occupied by one or more persons who normally have control over the movements of the vehicle, as in a manned aircraft or spacecraft, or who perform some useful function while in the vehicle.
MECHANORECEPTOR - a nerve ending that reacts to mechanical stimuli, as touch, tension and acceleration See also SENSOR.
METABOLISM - sum of the physical and chemical processes by which living organized substances are produced and maintained; also, the transformation by which energy is made available for the uses of the organism.
MICROORGANISM - minute, living organism, usually microscopic. Those of medical interest are bacteria, spiral organisms, rickettsia, viruses, molds, and yeasts.
MOTILITY - ability to move spontaneously.
MOTION SICKNESS - syndrome of pallor, sweating, nausea, and/or vomiting, which is induced by unusual accelerations. See also AIR SICKNESS.
NITROGEN CYCLE - exchange of nitrogen between animals and plants, in which plants convert urea or nitrates to protein; animals digest protein and excrete its nitrogen content as urea, which is taken up again by plants. See LIFE SUPPORT SYSTEM.
NITROGEN DESATURATION - reduction of the nitrogen content of the tissues of the body by breathing gases not containing nitrogen (e g., breathing a helium nitrogen mixture to eliminate nitrogen in the body).
NOCTURNAL - moving about at night, as nocturnal animals, birds, or insects Occurring during nighttime hours, as opposed to diurnal.
NUTRITION - the sum of the processes by which an animal or plant concentrates and assimilates food substances.
NYCTOTHERMAL - pertaining to both day and night it is used to describe rhythms (e g., nyctothermal rhythms of man).
NYSTAGMUS - involuntary rapid movement of the eyeball, which may be horizontal, vertical rotatory, or any combination of these, especially occurring as a result of eye fixations and stimulations of the inner ear during rotation of the body.
OPEN SYSTEM - system that provides for the body's metabolism m an aircraft or spacecraft cabin by removal of respiratory products and of waste from the cabin and by use of stored food and oxygen.
OPERATIVE TEMPERATURE - an equivalent or effective temperature parameter used m the study of human bioclimatology, one of several factors designed to measure the cooling effect of air on a human body under specific hypothetical conditions and apparel.
OPTICAL ACTIVITY - property possessed by many substances whereby plane polarized light in passing through them, undergoes a rotation of its plane of polarization, the angle of rotation being proportional to the thickness of the substance traversed by the light. See also POLARIMETRY.
ORIENTING-INVESTIGATORY REFLEX - response of an organism to any change in the environment.
ORTHOSTATIC TOLERANCE - ability to withstand immobilization in an erect position for a long period of time.
OTITIS - inflammation of the ear, which may be marked by pain, fever, abnormalities of hearing, deafness, tinnitus, and vertigo. See also OTITIS MEDIA.
OTITIS MEDIA - inflammation of the middle ear. See also OTITIS.
OTOLITH - dustlike substance made up of minute six-sided prisms of calcium otoconia carbonate arranged in a single layer in the gelatinous film which covers the maculae acustacae of the membranous labyrinth of the inner ear.
OXYGEN RECOVERY - the regaining of utilized oxygen from carbon dioxide and other metabolic compounds.
PARAFOVEAL VISION - vision in which the eye is so oriented toward the pertinent light source as to have the light fall on some portion of the retina surrounding the fovea. See also FOVEA.
PARTIAL PRESSURE SUIT - skintight suit which does not completely enclose the body but which is capable of exerting pressure on the major portion of the body to counteract an increased oxygen pressure in the lungs. See also PRESSURE SUIT.
PATHOLOGY - branch of medicine concerned with the essential nature of disease especially of the structural and functional changes in tissues and organs of the body which cause or are caused by disease.
PATHOMORPHOLOGY - perverted or abnormal morphology.
PATHOPHYSIOLOGY - physiology of disordered functions.
PAYLOAD - amount or character of the load carried by an aircraft, rocket, or spacecraft over and above that which is necessary for the operation of the vehicle for its flight.
PERMISSIBLE DOSE - dose of ionizing radiation which, in the light of present knowledge is not expected to cause appreciable bodily injury to a person during his lifetime. See also DOSIMETRY and DOSE and RADIATION DOSE.
PHOTORECEPTOR - sensory organ that responds to the stimulus of light waves The eye is the most familiar organ of this kind, but there are great varieties of visual systems among lower forms of living organisms The skin is a photoreceptor, although its response is evident only in the degree of pigmentation.
PHYSIOLOGICAL ACCELERATION - acceleration experienced by a human or an animal test subject in an accelerating vehicle. See also ACCELERATION and PHYSIOLOGY.
PHYSIOLOGY - science concerned with functions of living organisms or their parts, as distinguished from morphology, anatomy, etc.
PLANETARY QUARANTINE - sterilization and decontamination studies directed to the prevention of contamination of planets by terrestrial organisms so that the search for extraterrestrial life may have validity.
POSITIVE ACCELERATION - acceleration such that speed increases; accelerating force in an upward sense or direction, e.g., from bottom to top, or seat to head; acceleration in the direction in which this force is applied. See also ACCELERATION.
POSTHYPOXIA PARADOX - abrupt convulsive incident that may occur when a marked oxygen deficiency is relieved by sufficient oxygen; this contrasts with the normal rapid recovery from lack of oxygen. See also HYPOXIA and HYPEROXIA and ANOXIA.
PRESSURIZED - containing air or other gas, at a pressure higher than ambient. See also PRESSURIZED SUIT.
PRESSURIZED SUIT - suit designed to provide pressure directly on the body so that respiratory, circulatory, and other functions may continue as near normally as possible under low-pressure conditions occurring at high altitudes or in spaceflight without the use of a pressurized cabin. See also PRESSURIZED and C-SUIT.
PROPHYLACTIC - tending to ward off disease; a remedy that tends to ward off disease.
PROPHYLAXIS - prevention of disease; preventive treatment.
PSYCHOLOGY - science of the functions of the mind, such as sensation, perception, memory, and thought; and more broadly, the behavior of an organism in relation to its environment.
PSYCHOMOTOR ABILITY - of or pertaining to muscular action ensuing directly from a mental process, as in the coordinated manipulation of aircraft or spacecraft controls.
PSYCHONEURAL ACTIVITY - behavior of animals trained in what is termed an instrumental, place-learning situation.
PSYCHOPHYSICAL QUANTITY - a physical measurement, as a threshold, dependent on human attributes or perception.
PSYCHROPHILE - an organism whose optimum temperature for growth and reproduction is low (approximately 10-15°C for most cold-loving microorganisms).
RADIAL - general: issuing in rays, related to rays of light; medical: pertaining to the radius.
RADIATION - emission and propagation of energy through space or through a material medium in the form of waves (e g., electromagnetic radiation, sound waves, and elastic waves). The term radiation, or radiant energy, usually refers to electromagnetic radiation which is classified, according to frequency, as Hertzian or radiofrequency and microwave, infrared or heat, visible or light, ultraviolet, x-ray, and gamma (y) ray. See also CHEMICAL, DRY HEAT, INDICATOR (STERILITY), and STERILIZATION.
RADIATION DOSE - amount of radiation absorbed by a material, system, or tissue in a given amount of time usually measured in one of the commonly accepted units such as roentgen, roentgen-equivalent-man, or roentgen-equivalent-physical, etc. See also PERMISSIBLE DOSE and DOSE.
RADIATION SICKNESS (illness) - acute, self-limiting organic disorder following radiation and characterized by a group of signs and symptoms called the acute radiation syndrome, varying with the level or dose of whole-body irradiation received. Usual agents producing injury are gamma rays, x-rays, and fast and slow neutrons.
RADIOBIOLOGY - term used interchangeably with radiation biology; the science dealing with every step in the action of radiation on living matter, from the absorption of energy to injury and repair or death of the cell of the organism. Radiobiology has many facets: energy absorption; ionized and excited molecules; cell changes, biochemical lesions sub-microscopial lesions, visible lesions, and cell death; early physiological response to radiation; acute somatic response to radiation; delayed somatic effects; and mutations leading to genetic damage.
RADIO FREQUENCY - an electromagnetic wave frequency intermediate between audio frequencies and infrared frequencies, used in radio and TV transmission.
REFLEX - response; the organism's total response to a stimulus; responses are referred to as reflexes whether they are produced by classical conditioning or instrumental conditioning, involuntary reflexes versus voluntary reflexes.
RELIABILITY - suitable or fit to be relied on; trustworthy. Unlikely to break down or cause trouble.
REM - acronym for roentgen-equivalent-man.
RESPIRATION - act or function of breathing; the act by which air is drawn into and expelled from the lungs including inspiration and expiration.
RESTRAINT SYSTEM - physical device used to limit mobility. See also IMMOBILIZATION.
RETINA - innermost tunic and perceptive structure of the eye, formed by the expansion of the optic nerve and covering the back part of the eye.
REVERSE AFFERENTATION - feedback; the development of coordinated responses where afferent impulses from the muscles play a role in the regulation of the extent of muscular activity.
RHYTHM - movement marked by regular recurrence of or regular alternation in phenomena; hence, periodicity There are many different types of rhythm, including daily rhythm, diurnal rhythm, circadian rhythm, endogenous rhythm, nocturnal rhythm physiological rhythm, temperature rhythms, activity rhythm, and hormone-production rhythm.
SANITARY ENGINEERING - application of engineering principles to matters concerning health and the prevention of infection and disease.
SECOND SIGNAL SYSTEM - system of conditioned reflexes to verbal stimuli.
SELECTION - choosing for survival or elimination Theory under which organisms tend to produce progeny far above the means of subsistence; a struggle for existence ensues which results m the survival of those with favorable variations Since the favorable variations accumulate as the generations pass, the descendants tend to diverge markedly from their ancestors and to remain adapted to the conditions under which they live.
SENSATION - an impression conveyed by an afferent nerve to the sensorium commune.
SENSATION LEVEL - the level of psychophysiological stimulation above the threshold.
SENSE - a faculty by which the conditions or properties of things are perceived Hunger, thirst, malaise, and pain are varieties of sense, a sense of equilibrium, of well-being (euphoria), and other senses also are distinguished.
SENSOR - component of an instrument that converts an input signal into a quantity which is measured by another part of the instrument. See also MECHANORECEPTOR.
SIMULATOR, FLIGHT - training device to familiarize personnel with situations that are likely to be encountered in flight.
SLEEP-WAKEFULNESS - behavioral parameter related to performance with regard to varying amounts of sleep of an organism.
SOLAR FLARE - a bright eruption of the sun's chromosphere, ejecting high-energy protons which present a serious hazard to man in space.
SOLAR RADIATION - radiations from the Sun comprise a wide range of wavelengths m the electromagnetic spectrum, ranging from the short ultraviolet radiation at one end to the long infrared radiation at the other Fortunately for man, much of the energy toward either end of the spectrum is absorbed by the atmosphere, with the solar radiation on Earth being confined largely to the visible and near infrared.
SPACE BIOLOGY - see BIOASTRONAUTICS.
SPACE CAPSULE - container for conducting experiments during spaceflight.
SPACE MEDICINE - see AEROSPACE MEDICINE
SPACE STATION - a manned space platform in Earth's orbit, designed as a supply station for spacecraft
SPACE SUIT - a pressure suit for wear in space or at very low ambient pressures within the atmosphere, designed to permit the wearer to leave the protection of a pressurized cabin. See also PRESSURIZED SUIT and C-SUIT.
SPACECRAFT - devices, manned or unmanned, designed to be placed in orbit about the Earth or into a trajectory toward another celestial body.
STERILIZATION - complete destruction of all living organisms by application of heat chemicals, or radiation. See also CHEMICAL, DRYHEAT, and RADIATION.
STIMULUS - any agent, act, or influence that produces functional or trophic reaction in a receptor or in an irritable tissue; any event that initiates behavior; more specifically, any energy change that activates a sense organ.
STRESS - effect of a physiological, psychological, or mental load on a biological organism, which causes fatigue and tends to degrade proficiency.
SUBGRAVITY - condition in which the acceleration acting on a body is less than normal between zero and one g. See also GRAVITY.
TACHYCARDIA - very rapid beating of the heart; term is usually applied to a pulse rate above 100 per minute.
TELEMETRY - science of measuring and transmitting quantities (puIse rate , respiratory rate etc. ) to a distant station where they are interpreted and recorded.
TEMPERAMENT - a determinant of personality. Other determinants of the same order include demands, interests and capacities.
TEMPERATURE - intensity of heat as measured on a scale (Fahrenheit, Celsius) by means of various instruments.
TOLERANCE - ability to endure without ill effect, such as ability to endure the continued or increasing use of a drug.
TOXICOLOGY - sum of what is known regarding poisons; the scientific study of poisons,, their actions, their detection, and treatment of the conditions produced by them
TRACKING TASK - a sight experiment conducted during spaceflight or simulated spacefIight.
TYPOLOGY - study and especially analysis of division of humanity in terms of social types; of higher nervous activity - strength, balance, and mobility.
VELOCITY - rate of change of position or rate of displacement, expressed m feet (or centimeters) per second Velocity is a vector quantity; i. e, for its complete specification, its direction as well as its magnitude must be stated.
VENTILATION - biologically, the aeration of the lungs and blood by breathing; the inhalation and exhalation of air in the process of respiration.
VIABILITY - the state of being alive, capable of growth and reproduction, following exposure to an unfavorable environment.
VIBRATION - motion due to a continuous change in the magnitude of a given force, which reverses its direction with time.
WASTE CYCLING - conversion of metabolic waste products within a space cabin for the purpose of recovering potable water.
WATER IMMERSION - submersion in water for the purpose of studying some simulated effects of weightlessness, especially on the cardiovascular system.
WEIGHTLESSNESS - condition in which no acceleration within the system in question can be detected by an observer.
WORK-REST CYCLE - activity alternated with periods of respite, studied to measure psychophysiological performance under varying conditions.
X-RAY - non-nuclear electromagnetic radiation of very short wavelength, Iying within the interval of 01 to 100 angstroms (between gamma rays and ultraviolet radiation).
ZERO-C - see WEIGHTLESSNESS.