Search NASA⌕ Search

Engineering topics

Dietlein, L. F.

Publications and source records attributed to Dietlein, L. F..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Medical considerations for extending human presence in space

The prospects for extending the length of time that humans can safely remain in space depend partly on resolution of a number of medical issues. Physiologic effects of weightlessness that may affect health during flight include loss of body fluid, functional alterations in the cardiovascular system, loss of red blood cells and bone mineral, compromised immune system function, and neurosensory disturbances. Some of the physiologic adaptations to weightlessness contribute to difficulties with readaptation to Earth's gravity. These include cardiovascular deconditioning and loss of body fluids and electrolytes; red blood cell mass; muscle mass, strength, and endurance; and bone mineral. Potentially harmful factors in space flight that are not related to weightlessness include radiation, altered circadian rhythms and rest/work cycles, and the closed, isolated environment of the spacecraft. There is no evidence that space flight has long-term effects on humans, except that bone mass lost during flight may not be replaced, and radiation damage is cumulative. However, the number of people who have spent several months or longer in space is still small. Only carefully-planned experiments in space preceded by thorough ground-based studies can provide the information needed to increase the amount of time humans can safely spend in space.

Review, Tutorial↗
NASA NTRS1988

Medical considerations for extending human presence in space

The medical factors affecting the duration of manned space missions are reviewed. Topics addressed include the effects of weightlessness on body fluids, the cardiovascular system, red blood cells, the musculoskeletal system, the immune system, and the nervous system and the problems encountered in readaptation to normal gravity for each of these systems. Also discussed are the effects of radiation exposure, altered circadian rhythms, and closed environments. Plans for in-flight health care on the International Space Station are briefly outlined.

Leach, C. S.↗
NASA NTRS1983

Future thrusts in life sciences experimentation in space

Biomedical research objectives for future Shuttle and/or Space Station missions are discussed, with a focus on experiments exploring the physiological effects of microgravity. Experience up to the present is found to indicate that molecular-level processes are not much affected by the space environment, so that future experiments should concentrate on larger-scale phenomena. Areas considered include cardiovascular, respiratory, skeletal, and muscular physiology; metabolism; neurophysiology; and behavior. Radiation effects are seen as well as understood on the basis of ground-based data, with the possible exception of HZE-particle radiation. The need for carefully constructed ground research to prepare for space experiments is stressed.

Dietlein, L. F.↗
NASA NTRS1981

U.S. manned space flight: The first twenty years - A biomedical status report

In the last 20 years, the biomedical problems facing man in space have been brought into sharper focus. Space motion sickness is presently the most serious problem. Its etiology remains obscure, but the 'sensory conflict' theory appears most plausible. No valid predictive tests of susceptibility exist and presently medication for prevention or mitigation of symptoms must be relied on. Adaptation/biofeedback techniques may prove useful. Cardiovascular 'deconditioning' may be effectively attenuated by use of anti-g suits or plasma expanding techniques. Recent bedrest simulation studies would seem to indicate that concerns about chronically elevated central venous pressure during space flight are unfounded. The loss of red cell mass in space flight appears to be self-limited, independent of mission duration, and not of clinical concern, based on recent Soviet experiences. And finally, clodronate, a new diphosphonate effective in preventing hypercalciuria and negative calcium balance in normal human bedrested subjects, may prove effective in preventing or lessening skeletal mineral loss in space.

Dietlein, L. F.↗
NASA NTRS1977

Skylab: A beginning

A major goal of Skylab was to learn more about man and his responses to the space environment for missions lasting up to 84 days. A review of Skylab data pertaining to this goal is given.

Dietlein, L. F.↗
NASA NTRS1976

Biomedical results of the Skylab Program

Skylab, the fourth in a logical sequence of USA manned space flight projects following Mercury, Gemini and Apollo, presented life scientists with their first opportunity for an in-depth study of man's response to the space environment. Extensive medical investigations were undertaken to increase our understanding of man's adaptation to the space environment and his readaptation to gravity upon return to earth. The flight durations of the three Skylab missions were progressively increased from 28 days to 59 days and, finally, 84 days. The results of these investigations of the various body systems clearly denonstrated that man can adapt to zero gravity and perform useful work during long-duration space flight. However, definite changes (some unexpected) in the vestibular, cardiovascular, musculo-skeletal, renal and electrolyte areas were documented. The most significant were: the occurrence of space motion sickness early in the missions; diminished orthostatic tolerance, both in-flight and post-flight; moderate losses of calcium, phosphorus and nitrogen; and decreased tolerance for exercise post-flight. The mechanisms responsible for these physiological responses must be understood and, if necessary, effective countermeasures developed before man can endure unlimited exposure to space flight.

Michel, E. L.↗
NASA NTRS1975

The medical story

The paper discusses the medical program of the Skylab missions. The major medical systems discussed include the food system, the waste-management system, the personal-hygiene system, and the inflight medical support system. The life-sciences experiments conducted on Skylab are reviewed. These dealt with the cardiovascular system, mineral balance and bioassay of fluids, sleep, blood, metabolic activity, vestibular function, and time and motion studies. The medical operations were accomplished with only minor problems.

Johnston, R. S.↗
NASA NTRS1974

The Proceedings of the Skylab Life Sciences Symposium, Volume 1

The three manned Skylab missions resulted in biomedical experiment data in the areas of neurophysiology, musculoskeletal physiology, biochemistry, hematology, cytology, cardiovascular and respiratory metabolic functions: as well as detailed test objectives involving crew health and environment procedures. Major emphasis was placed on results from the last mission, Skylab 4, which covered 84 days of in-flight data collection. Many new norms were defined for normal man living and operating in a unique environment. While man is quite adaptable to this unique environment, many of the changes observed in Skylab require additional research for future flights lasting very long periods of time such as a Mars mission requiring 18 months.

Johnston, R. S.↗
NASA NTRS1974

The Proceedings of the Skylab Life Sciences Symposium, volume 2

The three manned Skylab missions resulted in biomedical experiment data in the areas of neurophysiology, musculoskeletal physiology, biochemistry, hematology, cytology, cardiovascular and respiratory metabolic functions: as well as detailed test objectives involving crew health and environment procedures. Major emphasis was placed on results from the last mission, Skylab 4, which covered 84 days of in-flight data collection. Many new norms were defined for normal man living and operating in a unique environment. While man is quite adaptable to this unique environment, many of the changes observed in Skylab require additional research for future flights lasting very long periods of time such as a Mars mission requiring 18 months.

Johnston, R. S.↗
NASA NTRS1974

Skylab: A beginning

Skylab biomedical experience indicates that man adapts well to and functions effectively in the space environment for time periods approaching three months. Appropriate dietary intake coupled with adequate, programmed exercise, sleep, work and recreation periods are essential to crew health and well being. No untoward physiological responses have been noted that would preclude longer duration space flights, but more research is required in order to understand the mechanisms involved in the observed responses. Remedial or preventive measures may be required for Mars-type missions, and further study of man in earth orbit for an uninterrupted six-month period should ideally precede this Mars-type mission.

Dietlein, L. F.↗
NASA NTRS1974

Medical results of the Skylab program

The Skylab food system, waste management system, operational bioinstrumentation, personal hygiene provisions, in-flight medical support system, and the cardiovascular counterpressure garment worn during reentry are described. The medical experiments program provided scientific data and also served as the basis for real-time decisions on flight duration. Premission support, in-flight operational support, and postflight medical activities are surveyed. Measures devised to deal with possible food spoilage, medical instrument damage, and toxic atmosphere caused by the initial failures on the Orbital Workshop (OWS) are discussed. The major medical experiments performed in flight allowed the study of physiological changes as a function of exposure to weightless flight. The experiments included studies of the cardiovascular system, musculoskeletal and fluid/electrolyte balance, sleep, blood, vestibular system, and time and motion studies.

Johnston, R. S.↗
NASA NTRS1974

The medical story

An overview of the Skylab medical program is given. All medical subsystems provided in the orbital workshop functioned satisfactorily. Major systems included the food system, the waste management system, and provisions per personal hygiene. A series of lockers in the wardroom was used to stow the inflight medical support system. Cardiovascular counter pressure garments were launched in the orbital workshop for all three crews. Life services experiments were carried out. Two experiments were conducted in the Skylab missions to study the performance of the cardiovascular system during weightless flight and return to earth and the one g environment. A series of experiments was conducted to study mineral balance and the bioassay of body fluids.

Johnston, R. S.↗
NASA NTRS1973

The effect of bedrest on adrenal function

Eight male subjects were subjected to continuous bedrest for 24-80 weeks for the purpose of studying metabolic responses. Three of the subjects did supine exercises daily during part of the study. Adrenal function was examined in relation to adrenal cortical and medullary excretions. The results reveal an increase in hydrocortisone throughout the test period, a decrease in norepinephrine and no change in epinephrine. These data suggest that exercise could decrease the severity of deconditioning caused by bedrest.

Leach, C. S.↗
NASA NTRS1972

Past and future space flight experiments on man and their spin-off contribution to world health.

The manned space-flight program has created some requirements which were new to the practice of medicine. The remoteness of the patient made it necessary to provide sensing and transmitting capability for various physiologic functions. The space and weight penalties in a spacecraft required that such sensors and related equipment be miniaturized and of a noninterfering nature as far as the crewmen were concerned. The need for continually increasing flight durations created a requirement for a type of equipment reliability previously unknown to medicine. The requirement to protect the crewmen against the environment of space and provide a habitable spacecraft has produced a series of ground-based medical applications.

Berry, C. A.↗
NASA NTRS1971

Inflight phonocardiogram, experiment M004

Electrocardiographic and phonocardiographic data were obtained from both the Gemini 4 and 5 crewmembers. The objective of Experiment M004 was the measurement and correlation of the various phases of the electrical and mechanical activity of the cardiac cycle, in an effort to gain insight into the cardiac functional status of crewmembers during long-duration space flight.

Dietlein, L. F.↗
NASA NTRS1971

Inflight exercise and work tolerance, experiment M003

The response of the cardiovascular system to a known exercise workload is used as index of the general physical condition of crewmembers during long duration space flight. Day-to-day evaluations of pulse rates before and after exercise periods were not remarkable. The response of the cardiovascular system to a calibrated workload was relatively constant for a given individual during space flights of as many as 14 days in connection with the Gemini Program.

Dietlein, L. F.↗