Space adaptation syndrome

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Space adaptation syndrome
Space adaptation syndrome acclimation.jpg
NASA astronauts acclimating themselves to space adaptation syndrome in a KC-135 airplane that flies parabolic arcs to create short periods of weightlessness. [1] In about two thirds of the passengers, these flights produce nausea, [2] [3] giving the plane its nickname "vomit comet".
Specialty Space medicine   OOjs UI icon edit-ltr-progressive.svg
Prevalence50% of individuals

Space adaptation syndrome (SAS) or space sickness is a condition experienced by as many as half of all space travelers during their adaptation to weightlessness once in orbit. [4] It is the opposite of terrestrial motion sickness since it occurs when the environment and the person appear visually to be in motion relative to one another even though there is no corresponding sensation of bodily movement originating from the vestibular system. [5]

Contents

Presentation

Space motion sickness can lead to degraded astronaut performance. [6] : 32  SMS threatens operational requirements, reduces situational awareness, and threatens the safety of those exposed to micro-g environments. [6] Lost muscle mass leads to difficulty with movement, especially when astronauts return to Earth. This can pose a safety issue if the need for emergency egress were to arise. Loss of muscle power makes it extremely difficult, if not impossible, for astronauts to climb through emergency egress hatches or create unconventional exit spaces in the case of a crash upon landing. Additionally, bone resorption and inadequate hydration in space can lead to the formation of kidney stones, and subsequent sudden incapacitation due to pain. [7] If this were to occur during critical phases of flight, a capsule crash leading to worker injury and/or death could result. Short-term and long-term health effects have been seen in the cardiovascular system from exposure to the micro-g environment that would limit those exposed after they return to Earth or a regular gravity environment. Steps need to be taken to ensure proper precautions are taken into consideration when dealing a micro-g environment for worker safety. [8] [9] Orthostatic intolerance can lead to temporary loss of consciousness due to the lack of pressure and stroke volume. This loss of consciousness inhibits and endangers those affected and can lead to deadly consequences. [10]

Cause

Your body just isn't built to deal with zero-gravity. But there's no way of predicting how someone will handle it. Someone who gets car-sick all the time can be fine in space - or the opposite. I'm fine in cars and on rollercoasters, but space is a different matter.

—  Steven Smith [11]

When the vestibular system and the visual system report incongruous states of motion, the result is often nausea and other symptoms of disorientation known as motion sickness. According to contemporary sensory conflict theory, such conditions happen when the vestibular system and the visual system do not present a synchronized and unified representation of one's body and surroundings. This theory is also known as neural mismatch, implying a mismatch occurring between ongoing sensory experience and long-term memory rather than between components of the vestibular and visual systems, emphasizing "the limbic system in integration of sensory information and long-term memory, in the expression of the symptoms of motion sickness, and the impact of anti-motion-sickness drugs and stress hormones on limbic system function. The limbic system may be the neural mismatch center of the brain." [12] At present a "fully adequate theory of motion sickness is not presently available" but at present the sensory conflict theory, referring to "a discontinuity between either visual, proprioceptive, and somatosensory input, or semicircular canal and otolith input", may be the best available. [13] Space adaptation syndrome or space sickness is a kind of motion sickness that can occur when one's surroundings visually appear to be in motion, but without a corresponding sense of bodily motion. This incongruous condition can occur during space travel when changes in g-forces compromise one's spatial orientation. [5] According to Science Daily , "Gravity plays a major role in our spatial orientation. Changes in gravitational forces, such as the transition to weightlessness during a space voyage, influence our spatial orientation and require adaptation by many of the physiological processes in which our balance system plays a part. As long as this adaptation is incomplete, this can be coupled to nausea, visual illusions, and disorientation." [5] Sleep deprivation can also increase susceptibility to space sickness, making symptoms worse and longer-lasting. [12]

According to the sensory conflict hypothesis, space sickness is the opposite of the kinds of motion-related disorientation that occur in the presence of gravity, known as terrestrial motion sickness, such as becoming carsick, seasick, or airsick. In such cases, and in contrast to space sickness, one's surroundings seem visually immobile (such as inside a car or airplane or a cabin below decks) while one's body feels itself to be in motion. Contemporary motion sickness medications can counter various forms of motion disorientation including space sickness by temporarily suppressing the vestibular system, but are rarely used for space travel because it is considered better to allow space travelers to adapt naturally over the first one to seven days rather than to suffer the drowsiness and other side effects of medication taken over a longer period. However, transdermal dimenhydrinate anti-nausea patches are typically used whenever space suits are worn because vomiting into a space suit could be fatal by obscuring vision or blocking airflow. Space suits are generally worn during launch and landing by NASA crew members and always for extra-vehicular activities (EVAs). EVAs are consequently not usually scheduled for the first days of a mission to allow the crew to adapt, and transdermal dimenhydrinate patches are typically used as an additional backup measure.

Management

Just as space sickness has the opposite cause compared to terrestrial motion sickness, the two conditions have opposite non-medicinal remedies. The idea of sensory conflict implies that the most direct remedy for motion sickness in general is to resolve the conflict by re-synchronizing what one sees and what one feels. For most (but not all) kinds of terrestrial motion sickness, that can be achieved by viewing one's surroundings from a window or (in the case of seasickness) going up on deck to observe the seas. For space sickness, relief is available via the opposite move of restricting one's vision to a small area such as a book or a small screen, disregarding the overall surroundings until the adaptation process is complete, or simply to close one's eyes until the nauseated feeling is reduced in intensity during the adjustment period. Some research indicates that blindness itself does not provide relief; "Motion sickness can occur during exposure to physical motion, visual motion, and virtual motion, and only those without a functioning vestibular system are fully immune. [12]

As with sea sickness and car sickness, space motion sickness symptoms can vary from mild nausea and disorientation to vomiting and intense discomfort; headaches and nausea are often reported in varying degrees. The most extreme reaction yet recorded was that felt by Senator Jake Garn in 1985 on Space Shuttle flight STS-51-D. NASA later jokingly began using the informal "Garn scale" to measure reactions to space sickness. In most cases, symptoms last from 2–4 days. When asked about the origins of "Garn", Robert E. Stevenson said: [14]

Jake Garn was sick, was pretty sick. I don't know whether we should tell stories like that. But anyway, Jake Garn, he has made a mark in the Astronaut Corps because he represents the maximum level of space sickness that anyone can ever attain, and so the mark of being totally sick and totally incompetent is one Garn. Most guys will get maybe to a tenth Garn if that high. And within the Astronaut Corps, he forever will be remembered by that.

Garn's purpose on the mission was in part to subject him to experiments on space motion sickness. [15] Predicting whether someone will experience space sickness is not possible. Someone who suffers from car sickness may not suffer from space sickness, and vice versa. [11] In excellent physical condition, Garn did not become sick on the vomit comet before STS-51-D. [15] All three astronauts on Skylab 3 suffered from nausea, although the three on Skylab 2 had not; the illness affected their work during the first few days, worrying NASA doctors. [16]

Experienced aviators and space travelers can suffer from space sickness. Garn began piloting at the age of 16 [15] and piloted a variety of military aircraft for 17,000 hours—more than any NASA astronaut—before STS-51-D. Charles D. Walker became ill on the same flight despite having flown on the shuttle before. [17] [18] While the Skylab 3 crew quickly recovered—whether by eating six smaller meals instead of three larger ones, or just by becoming used to space—one of the Skylab 4 crew became sick despite anti-nausea medication. [16] Steven Smith estimated that on four shuttle flights he threw up 100 times. [11]

Space sickness that occurs during space flight can also continue for days after landing, until the vestibular system has again adapted to gravity. [19]

History

In August 1961, Soviet cosmonaut Gherman Titov became the first human to experience space sickness on Vostok 2; he was the first person to vomit in space. [20]

Apart from that record, space motion sickness was effectively unknown during the earliest spaceflights (Mercury, Gemini series) probably because these missions were undertaken in spacecraft providing very cramped conditions and permitting very little room for head movements; space sickness seems to be aggravated by being able to freely move around, especially in regard to head movement, and so is more common in larger spacecraft. [21]

See also

Related Research Articles

<span class="mw-page-title-main">Motion sickness</span> Nausea caused by motion or perceived motion

Motion sickness occurs due to a difference between actual and expected motion. Symptoms commonly include nausea, vomiting, cold sweat, headache, dizziness, tiredness, loss of appetite, and increased salivation. Complications may rarely include dehydration, electrolyte problems, or a lower esophageal tear.

<span class="mw-page-title-main">Sense of balance</span> Physiological sense regarding posture

The sense of balance or equilibrioception is the perception of balance and spatial orientation. It helps prevent humans and nonhuman animals from falling over when standing or moving. Equilibrioception is the result of a number of sensory systems working together; the eyes, the inner ears, and the body's sense of where it is in space (proprioception) ideally need to be intact.

<span class="mw-page-title-main">Vestibular system</span> Sensory system that facilitates body balance

The vestibular system, in vertebrates, is a sensory system that creates the sense of balance and spatial orientation for the purpose of coordinating movement with balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of the inner ear in most mammals.

<span class="mw-page-title-main">Dizziness</span> Neurological condition causing impairment in spatial perception and stability

Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness.

Spatial disorientation is the inability to determine position or relative motion, commonly occurring during periods of challenging visibility, since vision is the dominant sense for orientation. The auditory system, vestibular system, and proprioceptive system collectively work to coordinate movement with balance, and can also create illusory nonvisual sensations, resulting in spatial disorientation in the absence of strong visual cues.

<span class="mw-page-title-main">Labyrinthitis</span> Medical condition

Labyrinthitis is inflammation of the labyrinth, a maze of fluid-filled channels in the inner ear. Vestibular neuritis is inflammation of the vestibular nerve. Both conditions involve inflammation of the inner ear. Labyrinths that house the vestibular system sense changes in the head's position or the head's motion. Inflammation of these inner ear parts results in a vertigo and also possible hearing loss or tinnitus. It can occur as a single attack, a series of attacks, or a persistent condition that diminishes over three to six weeks. It may be associated with nausea, vomiting, and eye nystagmus.

Airsickness is a specific form of motion sickness which is induced by air travel and is considered a normal response in healthy individuals. Airsickness occurs when the central nervous system receives conflicting messages from the body affecting balance and equilibrium. Whereas commercial airline passengers may simply feel poorly, the effect of airsickness on military aircrew may lead to a decrement in performance and adversely affect the mission.

<span class="mw-page-title-main">Effect of spaceflight on the human body</span> Medical issues associated with spaceflight

The effects of spaceflight on the human body are complex and largely harmful over both short and long term. Significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton. Other significant effects include a slowing of cardiovascular system functions, decreased production of red blood cells, balance disorders, eyesight disorders and changes in the immune system. Additional symptoms include fluid redistribution, loss of body mass, nasal congestion, sleep disturbance, and excess flatulence. A 2024 assessment noted that "well-known problems include bone loss, heightened cancer risk, vision impairment, weakened immune systems, and mental health issues... [y]et what’s going on at a molecular level hasn’t always been clear", arousing concerns especially vis a vis private and commercial spaceflight now occurring without any scientific or medical research being conducted among those populations regarding effects.

Up-down cues are human sensory cues built into an environment to indicate which direction is "up", even if "up" is arbitrary.

<span class="mw-page-title-main">Motion simulator</span> Type of mechanism

A motion simulator or motion platform is a mechanism that creates the feelings of being in a real motion environment. In a simulator, the movement is synchronised with a visual display of the outside world (OTW) scene. Motion platforms can provide movement in all of the six degrees of freedom (DOF) that can be experienced by an object that is free to move, such as an aircraft or spacecraft:. These are the three rotational degrees of freedom and three translational or linear degrees of freedom.

<span class="mw-page-title-main">Vertigo</span> Type of dizziness where a person has the sensation of moving or surrounding objects moving

Vertigo is a condition in which a person has the sensation that they are moving, or that objects around them are moving, when they are not. Often it feels like a spinning or swaying movement. It may be associated with nausea, vomiting, perspiration, or difficulties walking. It is typically worse when the head is moved. Vertigo is the most common type of dizziness.

The sopite syndrome is a neurological disorder that relates symptoms of fatigue, drowsiness, and mood changes to prolonged periods of motion. The sopite syndrome has been attributed to motion-induced drowsiness such as that experienced by a baby when rocked. Researchers Ashton Graybiel and James Knepton at the US Naval Aerospace Medical Research Laboratory first used the term "the sopite syndrome" in 1976, to refer to the sometimes sole manifestation of motion sickness, though other researchers have referred to it as "Sopite syndrome."

In psychophysical perception, the Coriolis effect is the misperception of body orientation due to head movement while under the effect of rotation, often inducing nausea. This effect comes about as the head is moved in contrary or similar motion with the body during the time of a spin. This goes on to affect the vestibular system, particularly the semicircular canals which are affected by the acceleration. This causes a sense of dizziness or nausea before equilibrium is restored after the head returns to a stabilized state. Crucially, this illusion is based entirely upon perception, and is largely due to conflicting signals between one's sight and one's perception of their body position or motion. Examples of situations where this can arise are circular acceleration and movement during a circular rotation.

<span class="mw-page-title-main">Weightlessness</span> Zero apparent weight, microgravity

Weightlessness is the complete or near-complete absence of the sensation of weight, i.e., zero apparent weight. It is also termed zero g-force, or zero-g or, incorrectly, zero gravity.

The spins is an adverse reaction of intoxication that causes a state of vertigo and nausea, causing one to feel as if "spinning out of control", especially when lying down. It is most commonly associated with drunkenness or mixing alcohol with other psychoactive drugs such as cannabis. This state is likely to cause vomiting, but having "the spins" is not life-threatening unless pulmonary aspiration occurs.

Space neuroscience or astroneuroscience is the scientific study of the central nervous system (CNS) functions during spaceflight. Living systems can integrate the inputs from the senses to navigate in their environment and to coordinate posture, locomotion, and eye movements. Gravity has a fundamental role in controlling these functions. In weightlessness during spaceflight, integrating the sensory inputs and coordinating motor responses is harder to do because gravity is no longer sensed during free-fall. For example, the otolith organs of the vestibular system no longer signal head tilt relative to gravity when standing. However, they can still sense head translation during body motion. Ambiguities and changes in how the gravitational input is processed can lead to potential errors in perception, which affects spatial orientation and mental representation. Dysfunctions of the vestibular system are common during and immediately after spaceflight, such as space motion sickness in orbit and balance disorders after return to Earth.

<span class="mw-page-title-main">Astronaut training</span> Preparing astronauts for space missions

Astronaut training describes the complex process of preparing astronauts in regions around the world for their space missions before, during and after the flight, which includes medical tests, physical training, extra-vehicular activity (EVA) training, wilderness survival training, water survival training, robotics training, procedure training, rehabilitation process, as well as training on experiments they will accomplish during their stay in space.

It is inevitable that medical conditions of varying complexity, severity and emergency will occur during spaceflight missions with human participants. Different levels of care are required depending on the problem, available resources and time required to return to Earth.

Simulator sickness is a subset of motion sickness that is typically experienced while playing video games from first-person perspective. It was discovered in the context of aircraft pilots who undergo training for extended periods of time in flight simulators. Due to the spatial limitations imposed on these simulators, perceived discrepancies between the motion of the simulator and that of the vehicle can occur and lead to simulator sickness. It is similar to motion sickness in many ways, but occurs in simulated environments and can be induced without actual motion. Symptoms of simulator sickness include discomfort, apathy, drowsiness, disorientation, fatigue, and nausea. These symptoms can reduce the effectiveness of simulators in flight training and result in systematic consequences such as decreased simulator use, compromised training, ground safety, and flight safety. Pilots are less likely to want to repeat the experience in a simulator if they have suffered from simulator sickness and hence can reduce the number of potential users. It can also compromise training in two safety-critical ways:

  1. It can distract the pilot during training sessions.
  2. It can cause the pilot to adopt certain counterproductive behaviors to prevent symptoms from occurring.

Virtual reality sickness occurs when exposure to a virtual environment causes symptoms that are similar to motion sickness symptoms. The most common symptoms are general discomfort, eye strain, headache, stomach awareness, nausea, vomiting, pallor, sweating, fatigue, drowsiness, disorientation, and apathy. Other symptoms include postural instability and retching. Common causes are low frame rate, input lag, and the vergence-accommodation-conflict.

References

  1. ↑ "Mixed Up in Space". NASA. 2001-08-07. Archived from the original on 2009-05-13. Retrieved 2009-05-28.
  2. ↑ Golightly, Glen (October 20, 1999). "Flying The Vomit Comet Has Its Ups And Downs". space.com. Archived from the original on 2006-03-10.
  3. ↑ "Reduced Gravity: Vomit Comet Blog". PhysicsCentral. May 10, 2005. Retrieved 2007-11-07.
  4. ↑ Quine, Tony (April 2007). "Addicted to space: An appreciation of Anousheh Ansari, Part II". Spaceflight. 49 (4): 144. ISSN   0038-6340.
  5. 1 2 3 "Why Do Astronauts Suffer From Space Sickness?". ScienceDaily. 2008-05-23.
  6. 1 2 Thornton, William; Bonato, Frederick (2017-10-23). The Human Body and Weightlessness. Cham, Switzerland: Springer. doi:10.1007/978-3-319-32829-4. ISBN   978-3-319-32828-7. OCLC   1006502642.
  7. ↑ Smith, Scott M.; Heer, Martina; Shackelford, Linda C.; Sibonga, Jean D.; Spatz, Jordan; Pietrzyk, Robert A.; Hudson, Edgar K.; Zwart, Sara R. (2015). "Bone metabolism and renal stone risk during International Space Station missions". Bone. 81: 712–720. doi:10.1016/j.bone.2015.10.002. PMID   26456109.
  8. ↑ Gunga, Hanns-Christian; Ahlefeld, Victoria Weller von; Coriolano, Hans-Joachim Appell; Werner, Andreas; Hoffmann, Uwe (2016-07-14). Cardiovascular System, Red Blood Cells, and Oxygen Transport in Microgravity. Cham, Switzerland: Springer. Bibcode:2016csrb.book.....G. doi:10.1007/978-3-319-33226-0. ISBN   978-3-319-33226-0. OCLC   953694996.
  9. ↑ Fritsch-Yelle, Janice M.; Leuenberger, Urs A.; D'Aunno, Dominick S.; Rossum, Alfred C.; Brown, Troy E.; Wood, Margie L.; Josephson, Mark E.; Goldberger, Ary L. (1998). "An Episode of Ventricular Tachycardia During Long-Duration Spaceflight". The American Journal of Cardiology. 81 (11): 1391–1392. doi:10.1016/s0002-9149(98)00179-9. PMID   9631987.
  10. ↑ Clément, Gilles (2011). Fundamentals of space medicine (2nd ed.). El Segundo, Calif.: Published jointly by Microcosm Press. ISBN   9781441999054. OCLC   768427940.
  11. 1 2 3 Leadbeater, Chris (2020-06-10). "The next astronaut on the moon will be a woman". The Telegraph. Retrieved 2020-06-17.
  12. 1 2 3 Lackner, J. R. (2014). "Motion sickness: More than nausea and vomiting". Experimental Brain Research. 232 (8): 2493–2510. doi:10.1007/s00221-014-4008-8. PMC   4112051 . PMID   24961738.
  13. ↑ Kohl, R. L. (1983). "Sensory conflict theory of space motion sickness: An anatomical location for the neuroconflict". Aviation, Space, and Environmental Medicine. 54 (5): 464–5. PMID   6870740.
  14. ↑ "Interview with Dr. Robert Stevenson" (PDF). Johnson Space Center Oral History Project. May 13, 1999. p. 35. Archived from the original (PDF) on 2008-03-08. Retrieved 2022-07-13.
  15. 1 2 3 Lamar, Jacob V. Jr.; Hannifan, Jerry (April 22, 1985). "Jake Skywalker: A Senator boards the shuttle". Time. Archived from the original on 2010-10-29. Retrieved April 13, 2011.
  16. 1 2 Elder, Donald C. (1998). "The Human Touch: The History of the Skylab Program". In Mack, Pamela E. (ed.). From Engineering Science to Big Science: The NACA and NASA Collier Trophy Research Project Winners. The NASA History Series. NASA. SP-4219.
  17. ↑ Bolden, Charles F. (January 6, 2004). "Charles F. Bolden". NASA Johnson Space Center Oral History Project (Interview). Interviewed by Johnson, Sandra; Wright, Rebecca; Ross-Nazzal, Jennifer. Houston, Texas. Retrieved 2020-06-19.
  18. ↑ Walker, Charles D. (14 April 2005). "Oral History Transcript". NASA Johnson Space Center Oral History Project (Interview). Interviewed by Johnson, Sandra.
  19. ↑ Kornilova, L. N.; Naumov, I. A.; Glukhikh, D. O.; Ekimovskiy, G. A.; Pavlova, A. S.; Khabarova, V. V.; Smirnov, Yu. I.; Yarmanova, E. N. (2017). "Vestibular function and space motion sickness". Human Physiology. 43 (5): 557–568. doi:10.1134/S0362119717050085. S2CID   39254942.
  20. ↑ Glenday, Craig, ed. (2012). Guinness World Records 2013 . Guinness World Records. p.  27. ISBN   9781904994879.
  21. ↑ Kozlovskaya, Inessa B.; et al. (2004). "The Effects of Long-Duration Space Flight on Eye, Head, and Trunk Coordination During Locomotion". NASA Johnson Space Center. Archived from the original on 2012-02-07. Retrieved 2008-02-07.
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