Space Future - Space Tourism and Space Medicine

Last year, I went to Florida to see off our Space Shuttle mission, Space Lab-J as an ex-Principal Investigator, and the originator of a medical experiment with carp. On that occasion, I visited Disney World together with my wife. An attraction we chose was a big roller coaster called the Space Mountain. We followed the waiting line for an hour. Then I noticed several senior couples left the line when they reached a sign post. Soon I found it said that persons with any one of the following symptoms may not ride on this vehicle; aged, high blood pressure or lumbago. Those who left the line must have obeyed the warning. I myself suffered from all of them, but didn't care. Fortunately, my wife did not read English. When our turn came, our seats happened to be at the front. It was a great experience in both physical and mental terms. My wife had to rest for thirty minutes afterward to recover from dizziness. I was quite all right and felt proud of the exciting experience.

On my return to Japan after this, I found a letter on my desk inviting me to make comments on the space tourism study today. The excitement I experienced in Disney World might have made me more aggressive than usual. I responded to the letter positively.

2. Safety First

I now remember with surprise what made me decide to take a ride on the thrilling Space Mountain. I think I completely trusted in the safety of the attraction; both the vehicle and its operation. When we fly with air lines, we believe the aircraft is absolutely safe, that is why we use it as transportation. This fact is apparently shown by the statistics of general aviation. Therefore, the most important condition for space tourism is safety. This is the premise of my comments to follow.

3. Space Environment and Medicine

At first, I would like to discuss the space environment from the medical point of view.

Atmosphere:

Most aircraft used for transportation are pressurized. The pressure level is equivalent to an altitude of 2700m for transoceanic flights. In the case of space vehicles the pressure program to match the rate of climb will be a key issue. The gas composition will be another issue, since the cabin atmosphere will be made of a mixture of gases carried in bottles.

Acceleration:

This is a special feature of space flight different from aircraft. At first, the high acceleration during ascent to space is inevitable. To our knowledge, the maximum endurable level of acceleration depends on the direction acting on the human body. Four G acting from head to foot will cause blackout, while two G is the maximum in the reverse direction. The relations of endurable G and direction of acceleration are shown by Figure in the next page.

In this figure, curve A is the case of water immersion, that is the human body in water. In this case, tolerable G levels are higher than 10 and tolerable time is 4 minutes for 10G. Other curves are acceptable if they are out side the solid line which represents a constant acceleration level and duration for typical launching conditions. It is most favorable for the acceleration level to be kept lower than 3 G.

Figure 1 Effect of back angle on tolerance to + Gz (1)

Rotation and Vibration:

Slow pitching and rolling motion will cause air sickness, but I do not know much about the motion of space launch vehicles. Vibration and acoustic noise should be eliminated for passenger transportation. It should be noted that many medical data including the diagram shown here are concerned with physiological limits, which are too severe for tourist passengers.

Weightlessness:

Space sickness is caused by weightlessness. Sea sickness can be compared to space sickness, but the conditions of seasickness which can be defined by the three symptoms of cold sweat, nausea and pale face are not observed in the case of space sickness. A person suffering from spacesickness suddenly throws up without bad feeling. It is necessary to make a medicine to cure the sickness. When one is space sick, it is difficult to eat medicine, so that an ointment type of medicine should be studied.

Spacesickness is the main medical problem for space tourism. In this space tourism study plan, the phase one tour was proposed based on the assumption that three hours flight in weightless condition would not cause spacesickness. I am skeptical about this assumption. At present astronauts undertake various forms of physical training, which seem to improve their durability against space sickness. I am afraid some ordinary people may become sick in several minutes, as in the case of seasickness. Human blood moves to the upper past of the body under weightless condition. This occurs even during the short period of the phase one tour.

Radiation:

The Atlantic anomaly located between the altitudes of 90 and 160 km over the southern Atlantic ocean will be considered to be dangerous to human bodies.

4. Physical Requirements of Space Tourists

In the scenario prepared for the proposed study, passengers are assumed to take a health inspection while they are enjoying rides on various types of attractions. This reminded me of my father's case. When he flew with airlines, there was a rule to reject aged persons who were older than seventy years old. But he always lied about his age. To make sure of this, I asked Japan Air Line if they had such old documents, but the answer was no.

For the future space tours, I hate to hang a sign to reject those who are "aged", and have "high blood pressure" and "lumbago". But we have to be careful of such a people who are determined to make their last tour to space. Actually the airlines have a simple criterion to check such a passenger. One such rule specifies warning against disease of the heart, low blood pressure, hypoxia and so on. However, some of these criteria are not clear, and so not useful. Thus, this is just an information for discussion.

5. Concluding Remarks

In conclusion, medical aspects of space tourism can be discussed in such a frame work like this, but I would like to emphasize that only a few accidents can damage the dream of space tourism. In this respect, we should study practical themes such as the best angle of reclining seat or the attitude of passengers during flight, based on the phase one tourism described in the scenario.

Reference

NASA

Genyo Mitarai graduated in 1946 from Nagoya University where he also received his M. D. degree in 1954. From 1967 he was a Professor in the Department of Aerospace Physiology, at the Research Inst. of Environ. Med., Nagoya University, until 1984 when he retired as the Director of the Institute. Then he was invited to Chukyo University as Professor, and was appointed Dean from 1989, retiring in 1992. He is now a lecturer of the University. His major fields have been electrophysiology of the retina, and equilibrium physiology. He proposed a medical experiment for the Japanese First Material Processing Test (FMPT) mission. After it was accepted, he worked for preparation of the flight as the Principal Investigator until his retirement from Nagoya University. Later the experiment was successfully carried out by his colleagues onboard Spacelab/Space Shuttle in 1992. Since 1962, he was a councillor of Japan Society of Space, Aviation and Environ. Med, for which he serves as Chairman of Board of Directors. He is member of many academic societies including the Japanese Rocket Society.


A comment presented at JRS Space Tourism Study Conference held on April 14, 1993. Edited and translated into English from taped transcript originally in Japanese. Originally published in the Journal of Space Technology and Science, Vol.9 No.1 '93 spring, pp.13-15	Space Tourism and Space Medicine
Exercise Physiology, School of Physical Ed.Chukyo University, Tokodate 101, Kaizu-cho, Toyota 470-03	Genyo Mitarai
	1. Introduction
Copyright � 1993 by Japanese Rocket Society. All rights reserved.	Last year, I went to Florida to see off our Space Shuttle mission, Space Lab-J as an ex-Principal Investigator, and the originator of a medical experiment with carp. On that occasion, I visited Disney World together with my wife. An attraction we chose was a big roller coaster called the Space Mountain. We followed the waiting line for an hour. Then I noticed several senior couples left the line when they reached a sign post. Soon I found it said that persons with any one of the following symptoms may not ride on this vehicle; aged, high blood pressure or lumbago. Those who left the line must have obeyed the warning. I myself suffered from all of them, but didn't care. Fortunately, my wife did not read English. When our turn came, our seats happened to be at the front. It was a great experience in both physical and mental terms. My wife had to rest for thirty minutes afterward to recover from dizziness. I was quite all right and felt proud of the exciting experience. On my return to Japan after this, I found a letter on my desk inviting me to make comments on the space tourism study today. The excitement I experienced in Disney World might have made me more aggressive than usual. I responded to the letter positively. 2. Safety First I now remember with surprise what made me decide to take a ride on the thrilling Space Mountain. I think I completely trusted in the safety of the attraction; both the vehicle and its operation. When we fly with air lines, we believe the aircraft is absolutely safe, that is why we use it as transportation. This fact is apparently shown by the statistics of general aviation. Therefore, the most important condition for space tourism is safety. This is the premise of my comments to follow. 3. Space Environment and Medicine At first, I would like to discuss the space environment from the medical point of view. Atmosphere: Most aircraft used for transportation are pressurized. The pressure level is equivalent to an altitude of 2700m for transoceanic flights. In the case of space vehicles the pressure program to match the rate of climb will be a key issue. The gas composition will be another issue, since the cabin atmosphere will be made of a mixture of gases carried in bottles. Acceleration: This is a special feature of space flight different from aircraft. At first, the high acceleration during ascent to space is inevitable. To our knowledge, the maximum endurable level of acceleration depends on the direction acting on the human body. Four G acting from head to foot will cause blackout, while two G is the maximum in the reverse direction. The relations of endurable G and direction of acceleration are shown by Figure in the next page. In this figure, curve A is the case of water immersion, that is the human body in water. In this case, tolerable G levels are higher than 10 and tolerable time is 4 minutes for 10G. Other curves are acceptable if they are out side the solid line which represents a constant acceleration level and duration for typical launching conditions. It is most favorable for the acceleration level to be kept lower than 3 G. Figure 1 Effect of back angle on tolerance to + Gz (1) Rotation and Vibration: Slow pitching and rolling motion will cause air sickness, but I do not know much about the motion of space launch vehicles. Vibration and acoustic noise should be eliminated for passenger transportation. It should be noted that many medical data including the diagram shown here are concerned with physiological limits, which are too severe for tourist passengers. Weightlessness: Space sickness is caused by weightlessness. Sea sickness can be compared to space sickness, but the conditions of seasickness which can be defined by the three symptoms of cold sweat, nausea and pale face are not observed in the case of space sickness. A person suffering from spacesickness suddenly throws up without bad feeling. It is necessary to make a medicine to cure the sickness. When one is space sick, it is difficult to eat medicine, so that an ointment type of medicine should be studied. Spacesickness is the main medical problem for space tourism. In this space tourism study plan, the phase one tour was proposed based on the assumption that three hours flight in weightless condition would not cause spacesickness. I am skeptical about this assumption. At present astronauts undertake various forms of physical training, which seem to improve their durability against space sickness. I am afraid some ordinary people may become sick in several minutes, as in the case of seasickness. Human blood moves to the upper past of the body under weightless condition. This occurs even during the short period of the phase one tour. Radiation: The Atlantic anomaly located between the altitudes of 90 and 160 km over the southern Atlantic ocean will be considered to be dangerous to human bodies. 4. Physical Requirements of Space Tourists In the scenario prepared for the proposed study, passengers are assumed to take a health inspection while they are enjoying rides on various types of attractions. This reminded me of my father's case. When he flew with airlines, there was a rule to reject aged persons who were older than seventy years old. But he always lied about his age. To make sure of this, I asked Japan Air Line if they had such old documents, but the answer was no. For the future space tours, I hate to hang a sign to reject those who are "aged", and have "high blood pressure" and "lumbago". But we have to be careful of such a people who are determined to make their last tour to space. Actually the airlines have a simple criterion to check such a passenger. One such rule specifies warning against disease of the heart, low blood pressure, hypoxia and so on. However, some of these criteria are not clear, and so not useful. Thus, this is just an information for discussion. 5. Concluding Remarks In conclusion, medical aspects of space tourism can be discussed in such a frame work like this, but I would like to emphasize that only a few accidents can damage the dream of space tourism. In this respect, we should study practical themes such as the best angle of reclining seat or the attitude of passengers during flight, based on the phase one tourism described in the scenario. Reference NASA CR-1205, Compendium of Human Responses to the Aerospace Environment, Nov. 1968, Fig. 7-8 in p.7-20. Genyo Mitarai graduated in 1946 from Nagoya University where he also received his M. D. degree in 1954. From 1967 he was a Professor in the Department of Aerospace Physiology, at the Research Inst. of Environ. Med., Nagoya University, until 1984 when he retired as the Director of the Institute. Then he was invited to Chukyo University as Professor, and was appointed Dean from 1989, retiring in 1992. He is now a lecturer of the University. His major fields have been electrophysiology of the retina, and equilibrium physiology. He proposed a medical experiment for the Japanese First Material Processing Test (FMPT) mission. After it was accepted, he worked for preparation of the flight as the Principal Investigator until his retirement from Nagoya University. Later the experiment was successfully carried out by his colleagues onboard Spacelab/Space Shuttle in 1992. Since 1962, he was a councillor of Japan Society of Space, Aviation and Environ. Med, for which he serves as Chairman of Board of Directors. He is member of many academic societies including the Japanese Rocket Society.