Limits...
Artificial gravity as a countermeasure for mitigating physiological deconditioning during long-duration space missions.

Clément GR, Bukley AP, Paloski WH - Front Syst Neurosci (2015)

Bottom Line: In spite of the experience gained in human space flight since Yuri Gagarin's historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of weightlessness on humans.Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth's surface, thereby avoiding the physiological deconditioning that takes place in weightlessness.Because researchers have long been concerned by the adverse sensorimotor effects that occur in weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented.

View Article: PubMed Central - PubMed

Affiliation: Wyle Science and Engineering Group Houston, TX, USA.

ABSTRACT
In spite of the experience gained in human space flight since Yuri Gagarin's historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of weightlessness on humans. Were astronauts to embark upon a journey to Mars today, the 6-month exposure to weightlessness en route would leave them considerably debilitated, even with the implementation of the suite of piece-meal countermeasures currently employed. Continuous or intermittent exposure to simulated gravitational states on board the spacecraft while traveling to and from Mars, also known as artificial gravity, has the potential for enhancing adaptation to Mars gravity and re-adaptation to Earth gravity. Many physiological functions are adversely affected by the weightless environment of spaceflight because they are calibrated for normal, Earth's gravity. Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth's surface, thereby avoiding the physiological deconditioning that takes place in weightlessness. Because researchers have long been concerned by the adverse sensorimotor effects that occur in weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented.

No MeSH data available.


Related in: MedlinePlus

Hypothetical comfort zone bounded by values of artificial gravity level and rotation rate based on theoretical studies in the 1960s (see Hall, 2009, for details). The “comfort zone” is the area in blue delimited by a maximum rotation rate of 6 rpm. According to the model of Stone and Letko (1965) the Coriolis and cross-coupled angular accelerations generated at these rotation rates during walking, climbing and handling materials should be the most comfortable for the crewmembers. However, very little experimental data were actually collected to validate this model. Recent data indicate that the limit of 6 rpm is overly conservative.
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Figure 2: Hypothetical comfort zone bounded by values of artificial gravity level and rotation rate based on theoretical studies in the 1960s (see Hall, 2009, for details). The “comfort zone” is the area in blue delimited by a maximum rotation rate of 6 rpm. According to the model of Stone and Letko (1965) the Coriolis and cross-coupled angular accelerations generated at these rotation rates during walking, climbing and handling materials should be the most comfortable for the crewmembers. However, very little experimental data were actually collected to validate this model. Recent data indicate that the limit of 6 rpm is overly conservative.

Mentions: The results of studies on humans living aboard slow rotating rooms in the 1960’s (Graybiel et al., 1960, 1965, 1969; Kennedy and Graybiel, 1962; Guedry et al., 1964) suggested that the lightest acceptable system for providing “comfortable” artificial gravity using a rotating spacecraft would be one rotating at 6 rpm at a radius ranging from 12–24 m, such as to create an artificial gravity level ranging from 0.3 G to 1 G (Stone and Letko, 1965; Figure 2). These theoretical limits to rotation rates and radii were based on casual observations of humans walking, climbing, moving objects, and performing nominal head movements in a large-radius centrifuge. These assumptions have largely been taken at face value as correct, but they need to be validated by experimental evidence. More recent data suggest that the adaptation limits of humans to rotating environment are much greater than these earlier studies had anticipated. For example, it has been observed that subjects in a rotating environment could tolerate a rotation rate up to 10 rpm provided that the exposure is progressive (Graybiel et al., 1965) or even up to 23 rpm after habituation of motion sickness symptoms (Young et al., 2001).


Artificial gravity as a countermeasure for mitigating physiological deconditioning during long-duration space missions.

Clément GR, Bukley AP, Paloski WH - Front Syst Neurosci (2015)

Hypothetical comfort zone bounded by values of artificial gravity level and rotation rate based on theoretical studies in the 1960s (see Hall, 2009, for details). The “comfort zone” is the area in blue delimited by a maximum rotation rate of 6 rpm. According to the model of Stone and Letko (1965) the Coriolis and cross-coupled angular accelerations generated at these rotation rates during walking, climbing and handling materials should be the most comfortable for the crewmembers. However, very little experimental data were actually collected to validate this model. Recent data indicate that the limit of 6 rpm is overly conservative.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470275&req=5

Figure 2: Hypothetical comfort zone bounded by values of artificial gravity level and rotation rate based on theoretical studies in the 1960s (see Hall, 2009, for details). The “comfort zone” is the area in blue delimited by a maximum rotation rate of 6 rpm. According to the model of Stone and Letko (1965) the Coriolis and cross-coupled angular accelerations generated at these rotation rates during walking, climbing and handling materials should be the most comfortable for the crewmembers. However, very little experimental data were actually collected to validate this model. Recent data indicate that the limit of 6 rpm is overly conservative.
Mentions: The results of studies on humans living aboard slow rotating rooms in the 1960’s (Graybiel et al., 1960, 1965, 1969; Kennedy and Graybiel, 1962; Guedry et al., 1964) suggested that the lightest acceptable system for providing “comfortable” artificial gravity using a rotating spacecraft would be one rotating at 6 rpm at a radius ranging from 12–24 m, such as to create an artificial gravity level ranging from 0.3 G to 1 G (Stone and Letko, 1965; Figure 2). These theoretical limits to rotation rates and radii were based on casual observations of humans walking, climbing, moving objects, and performing nominal head movements in a large-radius centrifuge. These assumptions have largely been taken at face value as correct, but they need to be validated by experimental evidence. More recent data suggest that the adaptation limits of humans to rotating environment are much greater than these earlier studies had anticipated. For example, it has been observed that subjects in a rotating environment could tolerate a rotation rate up to 10 rpm provided that the exposure is progressive (Graybiel et al., 1965) or even up to 23 rpm after habituation of motion sickness symptoms (Young et al., 2001).

Bottom Line: In spite of the experience gained in human space flight since Yuri Gagarin's historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of weightlessness on humans.Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth's surface, thereby avoiding the physiological deconditioning that takes place in weightlessness.Because researchers have long been concerned by the adverse sensorimotor effects that occur in weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented.

View Article: PubMed Central - PubMed

Affiliation: Wyle Science and Engineering Group Houston, TX, USA.

ABSTRACT
In spite of the experience gained in human space flight since Yuri Gagarin's historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of weightlessness on humans. Were astronauts to embark upon a journey to Mars today, the 6-month exposure to weightlessness en route would leave them considerably debilitated, even with the implementation of the suite of piece-meal countermeasures currently employed. Continuous or intermittent exposure to simulated gravitational states on board the spacecraft while traveling to and from Mars, also known as artificial gravity, has the potential for enhancing adaptation to Mars gravity and re-adaptation to Earth gravity. Many physiological functions are adversely affected by the weightless environment of spaceflight because they are calibrated for normal, Earth's gravity. Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth's surface, thereby avoiding the physiological deconditioning that takes place in weightlessness. Because researchers have long been concerned by the adverse sensorimotor effects that occur in weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented.

No MeSH data available.


Related in: MedlinePlus