Aerospace Physiology. Overview of Crew Systems team project Cardiopulmonary physiology. Musculoskeletal Vestibular Neurological Environmental Effects

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2 Crew Systems Design Problem Design a deep space habitat for operations in cislunar space Must support a nominal crew of four for a 180- day nominal mission (plus three contingency days) Choose configuration, size, and outfitting orientation Keep the pressure habitat structural mass below 5000 kg, using the following mass estimating relation M<kg>= 91 V pressurized <m 3 >

3 Crew Systems Design Problem Tasks Perform life support system trades studies and select life support systems Identify power requirements Select atmosphere and perform denitrogenation calculations for transition to 5 psi 80% O2 suit Perform interior layout of habitat (CAD) Placement of life support equipment and consumables Stowage Common crew areas Individual crew berths Airlock(s) 3

4 Design Problem Submissions Create Preliminary Design Review slide package for your design Follow guidelines from Engineering Graphics lecture, especially in maximizing information transfer and organizing the presentation to form a coherent, engaging story Grade will reflect both content from Crew Systems lectures and quality of presentation created 4

5 Crew Systems Project Teams Team B1: Klein, Douglas Ortiz, Oliver Mellman, Benjamin Shallcross, Michael Zittle, Kyle Team B2: Adamson, Colin Borillo Llorca, Irene Kunnath, Sarin Schneider, Mark Weber, Kristy Team B3: Downes, Alexander Kantzer, Michael Phillips, Brandyn Schaffer, Michael Team B4: Adams, Matthew Kumar, Rubbel Kunnath, Sahin Mittra, Atin Team B5: Brassard, Brianna Du Toit, Charl King, Jennifer Patel, Mihir Team B6: Horowitz, Matthew Levine, Edward Raghu, Nitin Wallace, Mazi 5 Team B7: Feeney, Matthew Moran, Ryan Muller, Brooks Ouyang, William Team B8: Cloutier, Kyle Garcia, Irving Gonter, Kurt Pashai, Pegah Team B9: Bhattarai, Ashok Ferguson, Kevin Gregorich, Donald Kittur, Chandan Team B10: Chattopadhyay, Rajarshi Garay, Samuel Todaro, Daniel Toothaker, Cody Team B11(G): Carlsen, Chris Rodriguez, Jon

6 The Human Respiratory System UNIVERSITY OF 6

7 Lung Measurements From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

8 Respiratory Volume vs. Exertion 8

9 Metabolic Processes Respiratory Quotient ( RQ ) RQ = Exhaled volume of CO 2 Inhaled volume of O 2 Function of activity and dietary balance Sugar: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O ( RQ =1.0) Protein: 2C 3 H 7 O 2 N + 6O 2 5CO H 2 O ( RQ = 0.83) Fat: C 57 H 104 O O 2 57CO H 2 O ( RQ = 0.71) For well-balanced diet, RQ~0.85 9

10 The Human Circulatory System 10

11 Blood Pressure in Circulatory System 11

12 Gas Exchange in the Lungs From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

13 Gas Exchange in the Tissues From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

14 Respiratory Problems Hypoxia Hypoxic Hypemic Stagnant Histotoxic Hyperoxia Hypocapnia Hypercapnia 14

15 Types of Hypoxia Hypoxic (insufficient O2 present) Decompression Pneumonia Hypemic (insufficient blood capacity) Hemorrhage Anemia Stagnant (insufficient blood transport) Excessive acceleration Heart failure Histotoxic (insufficient tissue absorption) Poisoning 15

16 Pressure Effects on Blood Oxygenation From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

17 Pressure Effects on Blood Oxygenation From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

18 Effects of Supplemental Oxygen From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

19 Hypoxia Effective Performance Time From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

20 Lung Overpressure Following Decompression From Nicogossian and Gazenko, Space Biology and Medicine - Volume II: Life Support and Habitability, AIAA

21 Oxygen Toxicity From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

22 Effects of ppco2 From James T. Joiner, NOAA Diving Manual, Fourth Edition, 2001 UNIVERSITY OF 22

23 Acute Effects of Hyperventilation From James T. Joiner, NOAA Diving Manual, Fourth Edition,

24 Gravity Effects on Arterial Pressure 320 mm 95/55 mmhg 120/80 mmhg 1200 mm 1000 mmh 2 O = 74.1 mmhg 210/170 mmhg 24

25 The Human Circulatory System, Revisited 25

26 Cardiovascular Effects of Microgravity Cardiovascular deconditioning Upper body blood pooling Changes in blood volume Increased calcium content 26

27 Acceleration Effects on Arterial Pressure 320 mm 25/ mmhg 120/80 mmhg 1200 mm At 4 g s longitudinal: 1000 mmh 2 O = 296 mmhg 475/435 mmhg 27

28 Supersaturation of Blood Gases Early observation that factor of two (50% drop in pressure) tended to be safe Definition of tissue ratio R as ratio between saturated pressure of gas compared to ambient pressure P N2 R = =0.79 (nominal Earth value) P ambient 50% drop in pressure corresponds to R=1.58 (R values of ~1.6 considered to be safe ) 28

29 Tissue Models of Dissolved Gases Issue is dissolved inert gases (not involved in metabolic processes, like N2 or He) Diffusion rate is driven by the gradient of the partial pressure for the dissolved gas dp tissue (t) = k [P alveoli (t) P tissue (t)] dt where k=time constant for specific tissue (min -1 ) P refers to partial pressure of dissolved gas 29

30 Solution of Dissolved Gas Differential Eqn. Assume ambient pressure is piecewise constant (response to step input of ambient pressure) Result is the Haldane equation: P tissue (t) =P tissue (0) + [P alveoli (0) P tissue (0)] 1 e kt Need to consider value of P alveoli P alveoli =(P ambient P H2O P CO2 + P O2 P alveoli = P ambient P H2O + 1 RQ ) Q RQ P CO2 Q where Q=fraction of dissolved gas in atmosphere ΔP O2 =change in ppo2 due to metabolism 30

31 Linearly Varying Pressure Solution Assume R is the (constant) rate of change of pressure - solution of dissolved gases PDE is 1 R P t (t) =P alv0 + R t P alv0 P t0 k k This is known as the Schreiner equation For R=0 this simplifies to Haldane equation Produces better time-varying solutions than Haldane equation Easily implemented in computer models e kt 31

32 Haldane Tissue Models Rate coefficient frequently given as time to evolve half of dissolved gases: ln (2) ln (2) k = T 1/2 = k T 1/2 Example: for 5-min tissue, k= min -1 Haldane suggested five tissue compartments : 5, 10, 20, 40, and 75 minutes Basis of U. S. Navy tables used through 1960 s Three tissue model (5 and 10 min dropped) 1950 s: Six tissue model (5, 10, 20, 40, 75, 120) 32

33 Workman Tissue Models Dr./Capt. Robert D. Workman of Navy Experimental Diving Unit in 1960 s Added 160, 200, 240 min tissue groups Recognized that each type of tissue has a differing amount of overpressure it can tolerate, and this changes with depth Defined the overpressure limits as M values 33

34 Workman M Values Discovered linear relationship between partial pressure where DCS occurs and depth M = M 0 + Md M=partial pressure limit (for each tissue compartment) M 0 =tissue limit at sea level (zero depth) ΔM=change of limit with depth (constant) d=depth of dive Can use to calculate decompression stop depth d min = P t M 0 M 34

35 Effect of Multiple Tissue Times 35

36 Physics of Bubbles Pressure inside a bubble is balanced by exterior pressure and surface tension P internal = P ambient + P surface = P ambient + 2 r where γ=surface tension in J/m 2 or N/m (=0.073 for water at 273 K) Dissolved gas partial pressure P g =P amb in equilibrium Gas pressure in bubble P int >P amb due to γ All bubbles will eventually diffuse and collapse 36

37 Bubble Formation and Growth In equilibrium, external pressure balanced by internal gas pressure and surface tension Surface tension forces inversely proportional to radius 37

38 Historical Data on Cabin Atmospheres from Scheuring et. al., Risk Assessment of Physiological Effects of Atmospheric Composition and Pressure in Constellation Vehicles 16th Annual Humans in Space, Beijing, China, May

39 Spacecraft Atmosphere Design Space from Scheuring et. al., Risk Assessment of Physiological Effects of Atmospheric Composition and Pressure in Constellation Vehicles 16th Annual Humans in Space, Beijing, China, May

40 Effect of Pressure and %O 2 on Flammability from Hirsch, Williams, and Beeson, Pressure Effects on Oxygen Concentration Flammability Thresholds of Materials for Aerospace Applications J. Testing and Evaluation, Oct

41 Atmosphere Design Space with Constraints from Scheuring et. al., Risk Assessment of Physiological Effects of Atmospheric Composition and Pressure in Constellation Vehicles 16th Annual Humans in Space, Beijing, China, May

42 Constellation Spacecraft Atmospheres from Scheuring et. al., Risk Assessment of Physiological Effects of Atmospheric Composition and Pressure in Constellation Vehicles 16th Annual Humans in Space, Beijing, China, May

43 Categories of Sensing Proprioception (internal to body) Self-Sensing Vestibular (inertial forces) Muscle and tendon sensors (extension) Joint sensors (angle) Exteroception (external to body) Visual Auditory Cutaneous 43

44 Anatomy of the Ear From James T. Joyner, ed., NOAA Diving Manual, Best Publishing, 2001 UNIVERSITY OF 44

45 Vestibular System From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

46 Vestibular Sense Organs From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

47 Thresholds of Rotational Perception Rotational accelerations Yaw: 0.14 deg/sec 2 Roll and Pitch: 0.5 deg/sec 2 Mulder s Constant Acceleration x excitation time = 2 deg/sec 5 deg/sec 2 x 0.5 sec -> sensed 10 deg/sec 2 x 0.1 sec -> not sensed Rotational velocities - minimum perceived rotation rates 1-2 deg/sec (all axes) 47

48 Otolith Responses From Roy DeHart, Fundamentals of Aerospace Medicine, Lea & Febiger,

49 Thresholds of Translational Perception a x : g a y : g a z : 0.01 g Apparent change in direction of g vector =

50 Space Motion Sickness Space Adaptation Syndrome 2/3 of astronauts report some effects Symptoms Primary: stomach discomfort, nausea, vomiting Secondary: pallor, cold sweats, salivation, depressed appetite, fatigue No correlation to susceptibility to motion sickness Primary hypothesis: sensory conflict (Treisman s Theory) 50

51 Progression of Space Motion Sickness From Roy DeHart, Fundamentals of Aerospace Medicine, Williams and Wilkins,

52 Space Motion Sickness Countermeasures Preflight training Desensitization Autogenic feedback training (AFT) Pharmaceuticals Oral - scopolamine/dex-amphetamine (Scopdex) Transdermal - scopolamine Intramuscular - promethazine Mechanical systems Pressurized insoles Load suits Neck restraints 52

53 Artificial Gravity g rotation =ω 2 r Lunar gravity Mars gravity 0.5*Earth gravity 0.75*Earth gravity Earth gravity Rotation Rate (rpm) 53

54 Allowable Rotation Rates Select groups (highly trained, physically fit) can become acclimated to 7 rpm 95% of population can tolerate 3 rpm Sensitive groups (elderly, young, pregnant women) may have tolerance levels as low as 1 rpm 54

55 The Origin of a Class X1 Solar Flare 55

56 Radiation Damage to DNA 56

57 Radiation Units Dose D= absorbed radiation 1 Gray =1 Joule kg = 100 rad = 10, 000 ergs gm Dose equivalent H= effective absorbed radiation 1 Sievert =1 Joule = 100 rem = 10, 000 ergs kg gm H = DQ rem = RBE rad LET = Linear Energy Transfer <KeV/µ m> 57

58 Radiation Quality Factor Radiation Q X-rays 1 5 MeV γ-rays MeV γ-rays KeV γ-rays 1.0 Electrons 1.0 Protons 2-10 Neutrons 2-10 α-particles GCR

59 Radiation in Free Space 59

60 Symptoms of Acute Radiation Exposure Radiation sickness : headache, dizziness, malaise, nausea, vomiting, diarrhea, lowered RBC and WBC counts, irritability, insomnia 50 rem (0.5 Sv) Mild symptoms, mostly on first day ~100% survival rem (1-2 Sv) Increase in severity and duration 70% incidence of vomiting at 200 rem 25%-35% drop in blood cell production Mild bleeding, fever, and infection in 4-5 weeks 60

61 Symptoms of Acute Radiation Exposure rem (2-3.5 Sv) Earlier and more severe symptoms Moderate bleeding, fever, infection, and diarrhea at 4-5 weeks rem ( Sv) Severe symptoms Severe and prolonged vomiting - electrolyte imbalances 50-90% mortality from damage to hematopoietic system if untreated 61

62 Symptoms of Acute Radiation Exposure rem ( Sv) Severe vomiting and nausea on first day Total destruction of blood-forming organs Untreated survival time 2-3 weeks rem ( Sv) Survival time ~2 weeks Severe nausea and vomiting over first three days 75% prostrate by end of first week rem (10-20 Sv) Severe nausea and vomiting in 30 minutes 4500 rem (45 Sv) Survival time as short as 32 hrs - 100% in one week 62

63 Long-Term Effects of Radiation Exposure Radiation carcinogenesis Function of exposure, dosage, LET of radiation Radiation mutagenesis Mutations in offspring Mouse experiments show doubling in mutation rate at rad (acute), 100 rad (chronic) exposures Radiation-induced cataracts Observed correlation at 200 rad (acute), 550 rad (chronic) Evidence of low onset (25 rad) at high LET 63

64 Radiation Carcinogenesis Manifestations Myelocytic leukemia Cancer of breast, lung, thyroid, and bowel Latency in atomic bomb survivors Leukemia: mean 14 yrs, range 5-20 years All other cancers: mean 25 years Overall marginal cancer risk deaths/million people/rem/year 100,000 people exposed to 10 rem (acute) -> 800 additional deaths (20,000 natural cancer deaths) - 4% 64

65 NASA Radiation Dose Limits 65

66 SPE and GCR Shielding Effectiveness Dose Equivalent, rem/yr GCR L. Hydrogen GCR Polyethylene GCR Graphite GCR Aluminum GCR Regolith SPE Graphite SPE Regolith SPE L. Hydrogen August 1972 SPE and GCR Solar Min Shielding Depth, g/cm 2 Francis Cucinotta, What s New in Space Radiation Risk Assessments for Exploration NASA Future In-Space Operations Telecon, May 18,

67 Density of Common Shielding Materials Polyethylene Water 67 Gr/Ep Acrylics Aluminum Lead

68 Comparative Thickness of Shields (Al=1) Polyethylene Water 68 Gr/Ep Acrylics Aluminum Lead

69 Comparative Mass for Shielding (Al=1) Polyethylene Water 69 Gr/Ep Acrylics Aluminum Lead

70 Shielding Materials and GCR Material Solar Minimum E (Sv) SPE + Solar Maximum Liquid H Liquid CH Polyethylene g/cm 2 Water Epoxy Aluminum Liquid H Liquid CH Polyethylene g/cm 2 Water Epoxy Aluminum Liquid H Liquid CH Polyethylene g/cm 2 Water Epoxy Aluminum

71 SPE and GCR Shielding Effectiveness 45-Year Old Male: GCR and Trapped Proton Exposure (%) Confidence to be below career limit Current Uncertainties With Uncertainty Reduction SAFE ZONE Solar Max Solar Max Solar Min Solar Min 50 Francis Cucinotta, What s New in Space Radiation Risk Assessments for Exploration NASA Future In-Space Operations Telecon, May 18, Days on ISS 71 Days on ISS

72 Deep Space Mortality Risks from GCRs Number of Days in Deep Space At Solar Minimum at 20 gm/cm 2 shielding with a 95% or 90% confidence level to be below 3% or 6% REID (Avg US pop) 3% Risk (REID) 6% Risk (REID) 95% CL 90% CL 95% CL 90% CL Age, y Males Age, y Females

73 References R. L. DeHart, ed., Fundamentals of Aerospace Medicine, Second Edition Williams and Wilkins, 1996 A. E. Nicogossian, C. L. Huntoon, and S. L. Pool, Space Physiology and Medicine, Third Edition Lea and Febiger, 1994 A. E. Nicogossian, S. R. Mohler, O. G. Gazenko, and A. I. Grigoriev, eds., Space Biology and Medicine (Volume III, Book 1: Humans in Spaceflight) American Institute of Aeronautics and Astronautics, 1996 J. T. Joiner, ed., NOAA Diving Manual: Diving for Science and Technology, Fourth Edition Best Publishing,

Aerospace Physiology. Lecture #11 Oct. 7, 2014 Cardiopulmonary physiology. Musculoskeletal Vestibular Neurological Environmental Effects MARYLAND

Aerospace Physiology. Lecture #11 Oct. 7, 2014 Cardiopulmonary physiology. Musculoskeletal Vestibular Neurological Environmental Effects MARYLAND Lecture #11 Oct. 7, 2014 Cardiopulmonary physiology Respiratory Cardiovascular Musculoskeletal Vestibular Neurological Environmental Effects 1 2014 David L. Akin - All rights reserved http://spacecraft.ssl.umd.edu