1、Introduction to Space Life Sciences,Gilles Clment, Ph.D,CNRS “Cerveau et Cognition“ Laboratory Toulouse, France,Kluwer Academic Publishers Copyright 2003 All rights reserved,Fundamentals of Space Medicine Chapter 1,Key Concepts,Space Life Sciences: What is it ? Where we are The historical context of
2、 human spaceflight How we got there The importance of continuing research before long-duration exploration missions can be safely undertaken Where do we go from here,Space Life SciencesWhat is it,Life Sciences are specifically devoted to the working of the living world (from bacteria and plants to h
3、umans) On Earth, all living organisms have developed as a result of constant exposure to 1-g gravity Space Life Sciences open a door to understanding ourselves, our evolution, the working of our world without the constraining barrier of gravity Beside microgravity, during space flight living organis
4、ms are also affected by ionizing radiation, isolation, confinement, changes in circadian rhythms (24-hr day/night cycle), etc. Objectives of space life sciences: Enhance fundamental knowledge in cell biology and human physiology Protect the health of astronauts Develop advanced technology and applic
5、ations for space and ground-based research,Justification for Human Spaceflight,Robotics versus Human crews = Apples versus Oranges Human Pros: intelligent operators, efficient end-effectors Human Cons: expensive, complexity of habitable environmentHuman spaceflight critics often discount the value o
6、f Life Sciences on the “Discovery Ledger (Big Book)” often due to following fundamentals differences: Physical Sciences: more concrete discoveries in relatively unexplored sphere Life Sciences: an inherently inexact science; context of background physiological variability; requirement for repeated m
7、easurements,Photo NASA,Space Medicine versus Space Physiology,Space Medicine To solve medical problems encountered in spaceflight Includes some adaptive changes (e.g., space motion sickness), environmental exposures, etc. Includes also some non-pathologic changes which become maladaptive on return t
8、o Earth (e.g., bone loss) Outlook is operational, views problems/peculiarities from standpoint of mission impactSpace Physiology To characterize response to space, especially 0-G Necessary knowledge base for above Outlook is investigational, views problems/peculiarities from standpoint of scientific
9、 return,Where we are (as of 1st July 03),Photo CNES,Total number of persons who have flown in space: 433 (41 ) Cumulative spaceflight time: 72 years (26.410 days) Mean spaceflight duration: 28 days Cumulative spaceflight duration by individual: Polyakov (679 days; 2 flights) Avdeyev (748 days; 3 fli
10、ghts) Re-adaptation to Earth gravity stated “ to be 90% complete after 6 years “ Valery Polyakov (during a science conference) How did we get there?,22 months,25 months,1783: Two French gentlemen ride a hot-air (Montgolfier) balloon,Major Space Life Sciences Events,1951: First successful (non-orbita
11、l) flight of a sounding rocket with a monkey and 11 mice (previous attempts since 1948 were not successful),1957: Dog Laika first living creature into orbit (died after a few days)followed by monkeys,Photo CNES,1959: Selection of 7 American astronauts,Major Space Life Sciences Events,1960: Selection
12、 of 11 Soviet cosmonauts,Photo NASA,Photo RSA,1965: First space walk (Extra-Vehicular Activity),1961: First human to orbit the Earth (Y. Gagarin) 1963: First woman (V. Tereshkova) in spacesecond Russian woman (S. Savitskaya) did not fly until 1982,Major Space Life Sciences Events,1965-66: Longest st
13、ay in space is 14 days (Gemini 7) first observations on human body adaptation artificial gravity first tested (Gemini 11),Major Space Life Sciences Events,70s : Salyut, Skylab start of detailed SLS investigations,1981: First space vehicle piloted during return (Shuttle),Photos NASA,2000: First exped
14、ition crew on board ISS,1994: Longest stay in space is 14 months (MIR),Human Spaceflight Experience,Adapted from Reschke and Sawin (2003),Human Spaceflight Experience greater than 30 days,Humans in Space,First space missions were to demonstrate that humans could survive a journey into space Some peo
15、ple doubted whether humans could endure the g forces of launch and re-entry, or swallow, or sleep in the absence of gravity Some predicted that “the bowels would not work without gravity, the heart might cavitate like a pump, or become so weakened as to prohibit return to Earth“,How long can humans
16、live in space, and how effectively can they work in space are still open questions Living and working is far different from merely surviving After extended stays in space, can people return safely to Earth and lead normal, healthy lives? Such questions are much more difficult than questions of survi
17、val because they require sophisticated scientific experimentation,Movie: 13_impossi,Surviving the Odyssey,What Really Occurs,No up or down disorientation, nausea,Fluids shift towards head puffy face, sinus congestion, headache, changes in smell and taste,Antigravity postural (extensor) muscles not u
18、sed new locomotion pattern, chicken legs, muscle strength and endurance decrease,Photos NASA,What Really Occurs,Bone density decreases by 1-3% per month,No up or down disorientation, nausea Fluids shift towards head puffy face, sinus congestion, headache, changes in smell and taste Antigravity postu
19、ral (extensor) muscles not used new locomotion pattern, chicken legs, muscle strength and endurance decrease,Fluids volume decreases changes in heart volume, heart rate, and blood pressure, breathing difficult (less red blood cells),What Really Occurs,Intervertebrate disks less compressed height inc
20、reases, back pain,Sleep disorders,No up or down disorientation, nausea Fluids shift towards head puffy face, sinus congestion, headache, changes in smell and taste Antigravity postural (extensor) muscles not used new locomotion pattern, chicken legs, muscle strength and endurance decrease Fluids vol
21、ume decreases changes in heart rate and blood pressure, breathing difficult (less red blood cells) Bone loss,Adapted from Lujan and White (1994),Photo NASA,No up or down disorientation, nausea Fluids shift towards head puffy face, sinus congestion, headache, changes in smell and taste Antigravity po
22、stural (extensor) muscles not used new locomotion pattern, chicken legs, muscle strength and endurance decrease Fluids volume decreases changes in heart rate and blood pressure, breathing difficult (less red blood cells) Bone loss Intervertebrate disks less compressed height increases, back pain Sle
23、ep disorders,What Really Occurs,Psychological troubles,Sharper vision, but light flashes (radiation),Photo NASA,Photo NASA,Issues for Human Missions,Preflight: Astronaut selection, crew selection, medical training Inflight: Acceleration, vibration, noise during launch and landing,Movie: 19_launch,Pr
24、eflight: Astronaut selection; crew selection; medical training Inflight: Acceleration; vibration; noise during launch and landing,Psycho-sociological issues (support) Environmental issues: toxic substances, pressure changes Extra-Vehicular activity (EVA): strain on muscles and bones, decompression-r
25、elated disorders,Physiological adaptation: heart (dys-rhythmias) and blood vessels, muscles (strength), bones (fractures, renal stones), nervous system, immune system (infection),Radiation (sterility, cancer),Crew medical officer: diagnosis, treatment (surgery),Emergency return,Issues for Human Miss
26、ions,Issues for Human Missions,Postflight: Piloting “1-g feels like 4-g“ Emergency egress Standing: orthostatic intolerance Walking: postural instability Motion sickness (Mal de Dbarquement) Muscle and bone weakness Decreased exercise capacity Return to flight status,Photo NASA,Countermeasures,2 dai
27、ly 1-hour sessions of exercise: Treadmill with axial loading Cycle ergometer Resistive exercise Traction on “bungee cords” Low Body Negative Pressure Fluid loading before re-entry,Photos NASA,Human Mars Mission,Challenges for a Mars Mission,Crew selection Onboard medical officer Radiation dose Bone
28、loss Advanced Life Support Systems,Spaceflight Life Support,Human requirements Hygiene, sanitation Nutrition (adequate, appealing) Rest (avoid chronic fatigue) Exercise (fitness, recreation, motivation) Human performance (psycho- social, workload, circadian factors) Life support systems Atmosphere,
29、temperature, lighting, noise Food, waste From physico-chemical (recycled) to bioregenerative (ecologically closed) Biosphere 2 Mir Greenhouse Bio-Plex,Photo NASA,Photo ESA,Greenhouse in Space,Critical questions to be addressed : How far can we reduce reliance on expendables? How well do biological a
30、nd physico-chemical life support technologies work together over long periods of time? Is a “steady state” condition ever achieved with biological systems? How do various contaminants accumulate and what are the long-term cleanliness issues?,Photo NASA,Challenges,Short-duration spaceflights presumab
31、ly OK for tourists For long-duration missions, the MIR experience indicates that current inflight countermeasures are not optimalUsing the current countermeasures methods, humans would not be operational after landing on Mars Artificial gravity probably the most efficient countermeasure,Photo CNES,M
32、ovie: 27_cosmonaut,Artificial Gravity,Principle of centrifugation,For interplanetary travel the design is most likely to be a short-arm centrifuge. combined with muscular exercise,Criteria for comfort (less motion sickness with lower angular velocity; low velocity means large radius),Recommended zon
33、e for effective human performance in rotating space systems,Photo NASA,Movie: 28_centrifuge,Movie: 28_hyperg,Future Research,Changes seen at cellular level. However, too much publicity on biochemical factories in space Plants in space. Life support systems: how to move from physico-chemical to close
34、d ecological life support systems Human Mars mission. Probably the longest period away from Earth to date; also probably the longest exposure to hypogravity (1/3 g) environment to date,Think about development of insects, amphibians, mammals after several generations without perceived gravity,Space L
35、ife Sciences research is on hold now,ISS should be ideal for study of fundamental biological processesnew science: gravitational physiology; no Nobel prize yet, but given prizes have been challenged,Document NASDA,Photo NASA,Movie: 29_frog,Benefits of SLS Research,Biology Improve overall health of p
36、eople of all ages Improve crop yields using less nutrients and smaller surface Advance understanding of cell behavior Biotechnology Provide information to design a new class of drugs to target specific proteins and cure specific diseases Culture tissue for use in cancer research/surgery and bone and
37、 cartilage injuries Biomedical Research Enhance medical understanding of the role of force on bone in disease processes including osteoporosis (bone loss) Advance fundamental understanding of the brain and nervous system and help develop new methods to prevent and treat various neurological disorder
38、s (e.g., multiple sclerosis) Develop methods to keep humans healthy in low-gravity environments for extended time periods Education Use science on orbit to encourage and strengthen science education on Earth,Additional Reading,Clment G (2003) Fundamentals of Space Medicine. Dordrecht: Kluwer Academi
39、c Publishers Mullane MR (1997) Do Your Ears Pop in Space? New York, NY: John Wiley & Sons Oser H, Battrick B (1989) Life Sciences Research in Space. ESA SP-1105. Paris, France: ESA Publication Division Wassersug RJ (2001) Vertebrate Biology in Microgravity. American Scientist 89: 46-53 Wolfe T (1979
40、) The Right Stuff. New York, NY: Farra, Straus & Giroux A Strategy for Research in Space Biology and Medicine in the New Century. National Research Council. Washington, DC: National Academy Press,1998 National Geographic. The Body in Space. January 2001 issue Fifth Symposium on the Role of the Vestibular Organs in Space Exploration. NASA SP-314, 1973 http:/www.nsbri.org/HumanPhysSpace/index.html http:/weboflife.arc.nasa.gov/ http:/lifesci.arc.nasa.gov/,
