Crew Systems Design Project ENAE 483 October 18, 2012 Rebecca Foust, Shimon Gewirtz, Matthew Rich, and Timothy Russell.

Crew Systems Design Project

ENAE 483October 18, 2012

Rebecca Foust, Shimon Gewirtz, Matthew Rich, and Timothy Russell

Mission Itinerary

• Days 1-3: Voyage to moon• Days 4-7: On the lunar surface– All three crew members will perform six hours of

extra-vehicular activity (EVA) daily• Days 8-10: Voyage back to Earth• Days 11-13: Contingency period– Plan for all three astronauts to be able to survive

inside the spacecraft

Design Constraints

• Spacecraft maximum diameter is 3.57 m• Half-cone angle of 25°• Wall thickness of 10 cm• Mass allocation for crew and crew systems is

1500 kg

95th Percentile Male Astronauts

• Spacecraft and all crew systems designed to support three 95th percentile male astronauts

• Taken under consideration during design of:– Neutral body position chairs– Toilet– Hatch and ladder for ingress and egress– Oxygen supply– Food and water storage– Window placements– Instrument panel placement

• Mass of each astronaut: 98.5 kg

Spacesuits

• Astronauts will use the Apollo 15-17 EMU because of its ability to operate at the required 5 psi, 80% O2

• As a soft suit, the EMU also has the advantage of being collapsible and thus requiring less cabin storage space when not in use than would a hard suit

• Mass of fully equipped suit: 96.2 kg• Volume of collapsed suit: 0.4 m3

Cabin Atmosphere• 80% oxygen, 20% nitrogen, 5 psi, 71 °F (295 K)

– Same atmosphere as spacesuits (no denitrogenation or depressurization needed)

– Oxygen density: 0.36 kg/m3

– Nitrogen density: 0.079 kg/m3

• Cabin atmosphere mass is 3.51 kg• 1% atmosphere lost daily to leakage

– Total 0.08 kg nitrogen lost– Total 0.37 kg oxygen lost

• 1.11 kg oxygen consumed per person-day– Total 43.3 kg oxygen lost

• Two options for EVA airlock cycles:– Evacuate all atmosphere for each cycle (“no recycling”)– Try to collect as much atmosphere as possible in storage tank prior to

each hatch opening (“recycling”)

No Cabin Atmosphere Recycling

• 100% atmosphere lost for each airlock cycle– Four airlock cycles– Total 2.52 kg nitrogen lost– Total 11.51 kg oxygen lost

• Need to supply extra:– 2.6 kg of nitrogen– 55.17 kg of oxygen

No Cabin Atmosphere Recycling• Gaseous storage of extra oxygen, nitrogen (3000 psi)

– Oxygen density: 270 kg/m3

– Nitrogen density: 236 kg/m3

– 2 kg of tank mass for every kg of gas– Total mass (tanks and gas): 177 kg– Total volume (tanks and gas): 0.287 m3

• Liquid storage of extra oxygen, nitrogen (49.7 atm, -119 °C)– Liquid oxygen density: 1140 kg/m3

– Liquid nitrogen density: 807 kg/m3

– 0.3 kg of tank mass for every kg of liquid– Vaporizer: 77 kg and 0.238 m3

– Total mass (tanks, liquid and vaporizer): 156 kg– Total volume (tanks, liquid and vaporizer): 0.307 m3

Cabin Atmosphere Recycling• 10% atmosphere lost for each airlock cycle• 90% atmosphere stored in collection tank as gas (3000

psi) and released after each airlock cycle– Four airlock cycles– 0.25 kg nitrogen lost– 1.15 kg oxygen lost

• Need to supply extra:– 0.33 kg of nitrogen– 44.8 kg of oxygen

• Vacuum pump: 26.6 kg, 0.026 m3

• Storage tank: 6.32 kg, 0.016 m3

Cabin Atmosphere Recycling• Gaseous storage of extra oxygen, nitrogen (3000 psi)

– Oxygen density: 270 kg/m3

– Nitrogen density: 236 kg/m3

– 2 kg of tank mass for every kg of gas– Total mass (tanks and gas): 172 kg– Total volume (tanks and gas): 0.265 m3

• Liquid storage of extra oxygen, nitrogen (49.7 atm, -119 °C)– Liquid oxygen density: 1140 kg/m3

– Liquid nitrogen density: 807 kg/m3

– 0.3 kg of tank mass for every kg of liquid– Vaporizer: 77 kg and 0.238 m3

– Total mass (tanks, liquid and vaporizer): 172 kg– Total volume (tanks, liquid and vaporizer): 0.333 m3

0 2 4 6 8 10 12 140

20

40

60

80

100

120

140

160

180

200

Atmosphere Storage Mass Trade Study

Gas No Recycle

Gas 90% Recycle

Liquid No Re-cycle

Liquid 90% Recycle

Mission Duration (days)

Mas

s (k

g)

0 2 4 6 8 10 12 140

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Atmosphere Storage Volume Trade Study

Gas No Recycle

Gas 90% Recycle

Liquid No Recycle

Liquid 90% Recycle

Mission Duration (days)

Volu

me

(m3)

Cabin Atmosphere

• Decided on liquid storage and no recycling– Lower mass is more critical than lower volume

• Total mass (tanks, liquid and vaporizer): 156 kg• Total volume (tanks, liquid and vaporizer): 0.307 m3

Particulate Scrubbing

• Placed near entrance of air-treating ducting• Activated Charcoal (based on the ISS trace contaminant

control system)– Carbon riddled with pores to adsorb particulates while letting air

flow through– Mass: 0.763 kg– Volume: 0.260 m3

• Fiberglass Filters– Allows air to flow through while trapping dust– Need four filters to trap over 90% of dust– Mass (four filters): 1 kg– Volume (four filters): 0.00655 m3

– Chosen because much lower volume for similar mass

Spacesuit Carbon Dioxide Scrubbing

• Total CO2 produced per astronaut:

• LiOH canister scrubbing:– Total mass required per astronaut: 2.09 kg – However, the mass of a single canister is 6.4 kg, which is the

minimum mass of LiOH that each astronaut can carry in his spacesuit– Total mass for 3 LiOH canisters: 19.2 kg

• METOX canisters have mass of 14.5 kg each, for a total mass of 43.5 kg for three canisters

• EMUs will employ LiOH canisters for CO2 scrubbing during EVA

1𝑘𝑔𝐶𝑂 2

𝑑𝑎𝑦×6h𝑜𝑢𝑟𝑠24h𝑜𝑢𝑟𝑠

×4𝑑𝑎𝑦𝑠=1𝑘𝑔𝐶𝑂2

CO2 Generation in Cabin• Each crew member generates 1 kg CO2 per day• On each non-EVA day, crew is in cabin at all

times and thus produces:

• On each EVA day, crew is in cabin for 18 of 24 hours and thus produces:

• Total CO2 produced:

1𝑘𝑔𝐶𝑂2

𝑝𝑒𝑟𝑠𝑜𝑛−𝑑𝑎𝑦×3𝑝𝑒𝑟𝑠𝑜𝑛𝑠=3

𝑘𝑔𝐶𝑂 2

𝑑𝑎𝑦

3𝑘𝑔𝐶𝑂2

𝑑𝑎𝑦×18 h𝑜𝑢𝑟𝑠24 h𝑜𝑢𝑟𝑠

=2.25𝑘𝑔𝐶𝑂2

𝑑𝑎𝑦

Cabin CO2 Scrubbing Options

• Disposable LiOH canisters– 2.09 kg for each kg of CO2 removed

• Disposable Ca(OH)2 canisters– 3.05 kg for each kg of CO2 removed

• 4-Bed Molecular Sieves (4BMS)– 30 kg for each kg of CO2 removed per day

0 2 4 6 8 10 12 140

20

40

60

80

100

120

CO2 Scrubbing Trade Study

LiOHCa(OH)24BMS

Mission Duration (days)

Mas

s (k

g)

Cabin CO2 Scrubbing Trade Study Results

• LiOH canisters require the least mass of the cabin CO2 scrubbing apparatuses

• 4BMS is only marginally more massive than LiOH canisters and has the additional benefit of handling humidity control

• The spacecraft will employ 4BMS for cabin CO2 scrubbing and cabin humidity control

LiOH (kg) Ca(OH)2 (kg) 4BMS (kg)75.24 109.8 90

Four Bed Molecular Sieve

• First two beds adsorb water vapor from the air– Humidity control– Adsorbed water vented into space

• Second two beds adsorb carbon dioxide– Carbon dioxide scrubbing– Adsorbed carbon dioxide vented into space

• Need to heat to ~400° C to regenerate• Total mass: 90 kg • Total volume: 0.33 m3 • Power draw: 510 W

Cabin Temperature Control

• The astronauts and the electrical equipment in the spacecraft generate heat, which must be rejected to maintain a comfortable cabin temperature

• The spacecraft employs a porous-plate sublimator as its atmospheric temperature control device

• Porous-plate sublimator operating principle: 1. Water in the sublimator extracts heat from the warm air2. Water seeps through the pores of nickel plates, the opposite ends of

which are exposed to the vacuum of space3. The water forms a layer of ice on the surface of the plate and

sublimes4. The air is chilled via this process of heat extraction and is then

recirculated into the cabin

Vacuum

PressurizedCabin

LOX LN2

Vaporizer

Porous Plate Sublimator

Fiberglass Dust Filters

4BMS CO2

H2O

Air

Cabin Atmosphere Conditioning Summary

Unpressurized StorageA. VaporizerB. N2 TankC. O2 TankD. Propellant TankE. Vapor Compression

Distillation UnitF. Multifiltration UnitG. Four Bed Molecular SieveH. Porous Plate SublimatorI. Particulate Filtration Unit

G

H

E

A C

B DI

F

Water Required

Use Amount of Water RequiredWater In Food 1.15 kg/person-day

Food Prep Water .76 kg/person-day

Drinking Water 1.62 kg/person-day

EVA Water 2.1 kg/person-day (4 EVA days)

Total Potable Water (for 3 people, 13 days)

167.87 kg

Water Required (cont.)Use Amount of Water RequiredHygiene Water 2.84 kg/person-dayTotal Hygiene Water (for 3 people, 13 days)

110.76 kg

Use Total Water Required (kg)Hygiene Water 110.76 Potable Water 167.87Total 273.63

Water RecyclingSystem Mass (kg) Volume (m3)Multifiltration 2.2 0.01Distillation 63 0.32Both 65 0.33

Vapor Compression Distillation was chosen because it is low-mass and low-wattage, while remaining within the volume constraints. Numbers shown are scaled back to accommodate the maximum water load on the system.

1 2 3 4 5 6 7 8 9 10 11 12 130

50

100

150

200

250

300

Water Required for Various Recycling Schemes

NoneHygieneAtmosphericUrineHygiene + AtmosphericHygiene + UrineAtmospheric+ UrineHygiene, Atmospheric + Urine

Day

Mas

s (kg

)

Water Recycling Summary

• Hygiene and Atmosphere and Urine water will be recycled through a multi-filtration system for use as hygiene water, then through a distillation system for use as potable water.

• The total mass required to support the trip with water recycling decreases to 86 kg, a reduction of 69% from the initial water mass of 274 kg, including the masses of the recycling systems.

• This will save an estimated 252 kg of water.

Food

• Expect each crew member to consume 0.674 kg of dry food each day

• Comprised of rehydratable food and consumable dry food

• Total mass of dry food: 26.3 kg• Total volume of dry food: 0.1 m3

Waste Management System• The spacecraft will employ a toilet whose dimensions are derived

from those of a squatting male:– 0.5 m wide by 0.526 m deep by 0.615 m tall

• Urinary and fecal waste will reside in a plastic bag in the base of the toilet until the next cabin depressurization cycle for EVA, at which time the astronauts will empty the bag outside of the spacecraft

• A plastic seal will be used to secure the closed lid of the toilet when exposed to microgravity

• Used toilet bags may be removed from the toilet and sealed and placed in stowage as necessary

• Toilet mass: 15 kg• Toilet volume: 0.16 m3

Clothes• The astronauts will wear disposable clothes rather than reusable

clothes to eliminate the need for additional water mass to wash clothes

• Budget 8 sets of clothing per astronaut over the duration of the mission– 1 set for each day on the moon, when physical exertion is highest (4

sets)– 1 set for every three days spent inside the spacecraft, including

contingency period (3 sets)– 1 extra set of clothes if needed

• Each set of clothes will have nominal mass 3 kg and nominal volume 0.0008 m3

• Total mass of clothing: 72 kg• Total volume of clothes: 0.02 m3

Neutral Body Posture Chair

•The chair is designed so that the astronaut will be on their back in neutral body posture during launch•After launch, the chair can be inclined to a seated position so that it takes up less space during the day, then reclined at night for sleeping. •The chair is molded to the astronaut’s body and includes restraints for sleeping in microgravity.•Varying sizes can be accommodated by swapping out the chairs. (95th percentile male chairs shown in slides for maximum volume case)

Radiation Protection

• We will put a thin layer of gold over the windows for visual protection from Sun– Same protection as space suit visors

• Aluminum hull provides radiation protection– Assuming the entire hull is 10 cm thick aluminum,

areal density of 27 g/cm2

– Corresponds to a solar maximum radiation exposure of 0.524 Sv (see next slide for regression)

– Mild symptoms of radiation poisoning

5 10 15 20 25 30 35 40 450.48

0.49

0.5

0.51

0.52

0.53

0.54

0.55

0.56

0.57

0.58

f(x) = 0.681749732708124 x^-0.080232336096623R² = 0.969286182602457

Radiation Exposure vs. Aluminum Areal Density

Areal Density (g/cm^2)

Sola

r Max

imum

Rad

iatio

n Ex

posu

re (S

v)

Floor Plans

• Chairs in neutral body posture on the astronaut’s back

• Reclined Chair footprint:– 1.82 x .615 m

Reclined Chair (Launch) Stowed Chairs

• Chairs in sitting position• Stowed chair footprint:

• .914x.615 m

• Inclining the chairs recovers .557 m2

Interior Views

Unpressurized Storage

Stowed Spacesuits

CTS BagsNBP Chairs Control Surface

Toilet

Cabin Through Hatch

•Hatch Height: 1.7 m

•Average Hatch Width: 0.7 m

Line of Sight: Side View

Line of Sight: Top View

Mass TableItem Mass (kg) Item Mass (kg)Crew 295.5 Toilet + Bags 15

Spacesuits 288.6 Clothes 72

Initial Cabin Air 3.5 Neutral Body Posture Chairs

210

O2 Supply + Tank 71.7 Ducting 20

N2 Supply + Tank 3.4 Intake and Supply Duct Fans

2

Cryogenic Vaporizer 77 Cargo Transfer Bags 30

Fiberglass Filters 1 Water + Distiller 86

4BMS 90 Dry Food 26.3

Porous Plate Sublimator

14.5 TotalDesign margin

1311.512.57%

Power RequirementsItem Power Draw (W)

Intake and Supply Duct Fans 200

Cryogenic Vaporizer 6

4BMS 510

Water Distiller 73.5

Water Filter 1.5

Total 791

References• John Duncan, “Portable Life Support System”, January 1999

http://www.apollosaturn.com/ascom/Lmnr/p.htm• NASA Lyndon B. Johnson Space Center, “Advanced Life Support Requirements Document”, February 2003

http://www.marsjournal.org/contents/2006/0005/files/Lange2003.pdf• Donald Rapp, “Mars Life Support Systems”, February 2006

http://spaceclimate.net/Mars.Life.Support.combo.pdf• International Academy of Astronautics, “Artificial Gravity Research to Enable Human Space Exploration”,

2009 http://iaaweb.org/iaa/Scientific%20Activity/Study%20Groups/SG%20Commission%202/sg22/sg22finalreportr.pdf

• MMR Technologies “Introduction to Vacuum Pump Usage” http://www.mmr-tech.com/PDFs/VacPumpReq_TSB007.pdf

• Paul E. DesRosiers, “Human Waste Studies in an Occupied Civil Defense Shelter”, July 1968 http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0671703

• A. J. Hanford, “Advanced Life Support Baseline Values and Assumptions Document”, August 2004 http://ston.jsc.nasa.gov/collections/TRS/_techrep/CR-2004-208941.pdf

• J.A. Steele, "Water Management System Evaluation for Space Flights of One Year Duration", NASA-CR-168484, October 1953 http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19820067073_1982067073.pdf