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Advanced Topics in Space Studies: Commercial Barriers and Solutions Human Factors/Space Medicine Dr. John M. Jurist Biophysicist CRM, Inc.

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Presentation on theme: "Advanced Topics in Space Studies: Commercial Barriers and Solutions Human Factors/Space Medicine Dr. John M. Jurist Biophysicist CRM, Inc."— Presentation transcript:

1 Advanced Topics in Space Studies: Commercial Barriers and Solutions Human Factors/Space Medicine Dr. John M. Jurist Biophysicist CRM, Inc.

2 What Happens to People Living and Working in Space? The dream:

3 What Happens to People Living and Working in Space? Reality:

4 Human Factors Space is a very, very hostile and unforgiving place: 1.None of the comforts of home unless brought along 2.It is largely empty (both blessing and curse) 3.Transport from Earth is very expensive 4.We dont really know much about living there 5.Repairs and help are far away 6.Truism: Space can always hurt you more

5 Human Factors 862 gms O 2 2,200 gms H 2 O 523 gms food 982 gms CO 2 2,542 gms H 2 O 61 gms solid waste (min) Consumables for a 70 kg Man (level flying) at 2,830 kcal/day on specific diet: (after Hans G. Clamann, Problems of Metabolism in Sealed Cabins)

6 Human Factors 1.Air 2.Water/urine 3.Food/solid wastes 4.Toxic accumulations of whatever Consumables requirements make recycling more attractive for longer missions and larger crews:

7 Human Factors Considered in the context of mission parameters: 1.Suborbital 2.Orbital 3.Lunar 4.Solar System

8 Human Factors Considered in the context of mission parameters: 1.Duration 2.Life Support 3.Consumables 4.Acceleration 5.Microgravity 6.Radiation 7.Other Considerations

9 Human Factors Suborbital: 1.Duration – minutes 2.Life support – hypoxia – pressure suits 3.Consumables – minimal – no waste handling 4.Acceleration – multidirectional? – cardiac arrhythmias 5.Microgravity – nausea (in a pressure suit?) 6.Radiation – negligible

10 Human Factors Orbital: 1.Duration – hours to weeks 2.Life support – + contaminants, noise 3.Consumables – +transported and stored 4.Acceleration – + tolerance after microgravity 5.Microgravity – +fluid shift, bone & muscle atrophy 6.Radiation – not negligible 7.Other – medical emergencies – cant call 911

11 Human Factors Lunar: 1.Duration – hours to weeks 2.Life support – + contaminants, noise 3.Consumables – +transported and stored 4.Acceleration – + tolerance after microgravity 5.Microgravity – +fluid shift, bone & muscle atrophy 6.Radiation – roughly 2x orbital, flares fatal 7.Other – dust, medical emergencies, procreation?

12 Pulmonary Physiology Abating effects of altitude: 1.Pressurize the cabin – 8,000 feet airline standard 2.Supplemental oxygen

13 Pulmonary Physiology Pressurizing cabin to 8,000 feet results in inadequate oxygen saturation and need for additional oxygen for otherwise healthy people: 1.44% of 65 year old 2.27% of 55 year old 3.14% of 45 year old

14 Pulmonary Physiology Breathing pure oxygen at altitude equivalent to: 1.Sea level air at 33,000 feet 2.10,000 feet air at 39,000 feet 3.20,000 feet air at 45,000 feet

15 Pulmonary Physiology Pressure suits: 1.Full pressure suit more than $1 Million 2.EVA capable suit more than $3 Million 3.Partial pressure suits uncomfortable -- Get me down alive !! 4.Poor heat dissipation especially with exercise 5.Heat stroke running from downed spacecraft?

16 Acceleration Effects Acceleration duration: 1.Prolonged if more than 0.2 seconds 2.Fluid shifts important and dominate effects 3.Impact if less than 0.2 seconds 4.Viscoelastic nature of tissues 5.Delta-V or acceleration onset best indicator

17 Acceleration Effects Acceleration definitions: 1.Eyeballs down plus G z 2.Eyeballs up minus G z 3.Eyeballs in plus G x 4.Eyeballs out minus G x

18 Acceleration Effects Prolonged acceleration: 1.Normal blood pressure at heart 120/75 mm Hg 2.Pulmonary artery 20/7 mm Hg 3.Pressure drop to brain 35 mm Hg at 1 G 4.Pressure drop to brain of 105 mm Hg at 3 G 5.Venous blood pooling

19 Acceleration Effects Prolonged acceleration: 1.Grey out, loss of vision, loss of consciousness 2.Visual acuity decrease (deformation) 3.Compensatory mechanisms 4.Carotid sinus reflex dominates (5 seconds) 5.Respiratory difficulties

20 Acceleration Effects Abating effects of prolonged acceleration: 1.Decrease uphill heart-brain distance 2.Modify flight profile 3.Counter pressure suit to decrease blood pooling 4.Counter pressure by straining

21 Acceleration Effects Cardiac effects of prolonged acceleration: 1.Irregular heart beat 47% medical professionals 2.4.5% potentially dangerous 3.Irregular heart beat 30-50% fighter pilots 4.4.6% potentially dangerous 5.Aging effects poorly characterized

22 Consideration of Failure Fundamental decisions : 1.Vertical or horizontal takeoff and landing 2.FAA/AST-2 essentially laissez faire 3.Definition of failure modes and probabilities 4.Passenger education and training

23 Consideration of Failure Ejection seat utility: 1.Part of atmospheric flight 2.HTO vehicle in early flight 3.Limited at high speeds 4.Limited at high stagnation temperatures

24 Consideration of Failure Ejection seat upper envelope: 1.Mach 0.9 at sea level 2.Mach 3.7 at 65,000 feet 3.High stagnation temperatures above 65,000 feet

25 Consideration of Suborbital Failure Cabin depressurization: 1.Unstrap for short time in microgravity? 2.Emergency egress for landing mishaps 3.Lawyers have hindsight 4.So do congressional committees

26 Radiation Exposure Sources of exposure: 1.On board fluid level sensors 2.Cosmic photons (includes gamma bursts) 3.Cosmic particulate radiation 4.Solar photons 5.Solar particulate radiation (includes flares) 6.Trapped particulate radiation belts (Van Allen) 7.Terrestrial background

27 Radiation Exposure Units: Energy/MassBioeffect 100 Rad times Q(RBE) 100 Rem 1 Gray (Gy)times Q 1 Sievert (Sv)

28 Radiation Exposure Short term acute whole body exposure (rems): 10-50Minor blood changes % nausea (1 day), blood, survivable /4-1/2 nausea (1 day), blood, GI, survivable Most nausea (1 day), blood, GI, 5-50% die LD 50 Most nausea, blood, GI, 50-90% die Nausea (hours), blood, GI, almost all die 750-1,000Nausea (hours), blood, GI, fatal (2-4 weeks) 1,000-2,000Nausea (hours), fatal (2 weeks) 4,500Incapacitation (hrs), fatal (1 week)

29 Radiation Exposure Living and medical: 1.Polar airline flight mSv per day 2.2 view chest X-ray mSv 3.Bone scan 0.15 mSv 4.Chest CT mSv (typical 10 mSv) 5.Billings MT background 1.2 mSv per year (quiet sun) 6.Typical US background 2.4 mSv per year 7.Typical US medical 0.6 mSv per year

30 Radiation Exposure

31 Based on HTO suborbital: 1.Upper limit mSv per flight 2.Polar airline flight mSv per day

32 Radiation Exposure Based on orbital and beyond: mGy/day (Skylab) mGy/day (Apollo landing flights) 3.~0.06 mGy/day (STS) mGy/day (STS-2, STS-31) mGy/day mSv/day galactic cosmic mGy/day mSv/day trapped belt

33 Radiation Exposure The problem: 1.2 view chest X-ray mSv 2.Public limit 1 mSv per year 3.NASA classifies astronauts as radiation workers 4.Worker whole body 50 mSv or 0.05 Sv per year 5.Worker organ limit 0.5 Sv per vear 6.Worker organ limit 0.25 Sv per month

34 Radiation Exposure Career limits for radiation workers (1994): Blood-Forming Organs Limit atLensSkinMaleFemale Age Sv6.0 Sv1.5 Sv1.0 Sv Age Sv6.0 Sv2.5 Sv1.75 Sv Age Sv6.0 Sv3.2 Sv2.5 Sv Age Sv6.0 Sv4.0 Sv3.0 Sv

35 Radiation Exposure Radiation carcinogenesis: 0.5/10 6 /mSv/yearBreast 0.4/10 6 /mSv/yearThyroid 0.3/10 6 /mSv/yearLung 7-17/10 6 /mSv/yearAll cancers 100 mSv/ deaths added to 20,000 w/o radiation (4% increment/10 rads) 10 mSv/year cont.5% increment/1 rad lifetime increase

36 Radiation Exposure Is radiation a show-stopper for a trip to Mars? 1.Minimum energy transfer roughly 9 months each way 2.Assume STS-like free space galactic radiation exposure of mSv/day days times mSv/day = 39.4 mSv for 1 way 4.Is it legal? 50 mSv/year whole body worker limit 5.Is it legal? Compare to career limits (3 Sv age 55) 6.Boost cancer death risk 1.7% for baseline trip to Mars 7.Boost cancer death risk 25% for continuous mSv/day 8.Flares and Mars orbit time, surface time 9.Radiation issues become significant

37 Radiation Exposure The conundrums: Are long term space missions legal? Informed consent vs. legal limitations Conceive and raise children? Remember planets shield by geometry Large variability in exposure (flares) Large variability in response

38 Weightlessness Based on HTO suborbital: 1.Maximum of 3½ minutes of microgravity 2.Greatest risk is nausea (other risks in orbit) 3.Familiarization aircraft flights 4.Minimize head movements 5.Medication 6.Avoid vomiting into oxygen mask or closed helmet 7.Nausea is contagious (smells and sounds)

39 Discussion

40 Suborbital Human Factors Status Alt.space awaremess is dismal: 1.Assumption that it is accomplished and can be ignored 2.Lack of appreciation of risks 3.Aging normative population undefined 4.Suborbital floating free in shirt sleeves? 5.Buy a Russian space suit on EBAY

41 Orbital (and Beyond) Human Factors Status Alt.space awaremess is even more dismal: 1.Assumption that it is accomplished and can be ignored 2.Lack of appreciation of risks 3.Aging normative population undefined 4.Minimal gravity level is undefined 5.Radiation issues become significant 6.Working is microgravity is hard

42 Orbital (and Beyond) Human Factors Status Why? Culture shock (engineering vs. biomedical): Engineers look for limiting parameters Engineers design to limiting parameters Engineers minimize variables Human responses vary enormously Human responses probabilistic Human responses – many variables Human responses poorly characterized Never say never in medicine

43 Orbital (and Beyond) Human Factors Status Medical issues related to living in space and going to Mars: 1.Outside assistance is impossible or very difficult 2.Life support degradation – toxin accumulation 3.Acute urinary retention -- renal lithiasis 4.Cardiac event 5.Cancer (Antarctica example) 6.Drug shelf life (accelerated degradation with radiation) 7.Medical/surgical infrastructure -- how much is enough?

44 Opportunities What we dont know can hurt us or provide opportunities for play/research: 1.Microgravity – musculoskeletal, cardiovascular, reproductive, and immune systems; embryogenesis, fetal development; aging; optimization 2.Radiation – shielding (mass, electrostatic, or magnetic), abatement (pharmaceutical, antioxidants, modification of humans – genetic engineering) 3.Long term exposure to different gas mixes vs. standard air 4.Other – lunar dust and urban/rural pollution effects

45 Opportunities Role for small business niche operations: 1.Training MDs in aerospace medicine 2.Training passenger candidates 3.Screening passenger candidates 4.Space Camp for passengers 5.Life support equipment – esp. pressure suits 6.Ever present consulting

46 Opportunities Role for academic operations: 1.Training MDs in aerospace medicine 2.Training passenger candidates 3.Education – public outreach 4.Research – specialized – intradepartmental 5.Research – interdisciplinary – multidepartmental or multischool 6.Ever present consulting

47 Solutions Becoming a spacefaring culture: 1.Drive down cost to LEO and beyond 2.Find and exploit commercial opportunities 3.Justification for manned presence 4.Technology (microgravity, radiation, life support) 5.Technology (shorten trip times) 6.Motivation (national security?, lifeboat?)

48 Solutions Becoming a spacefaring culture: 1.Time 2.Money 3.Research 4.Technology 5.Management 6.Motivation


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