Crew Systems Design Project
ENAE 483
October 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
Atmosphere Storage Mass Trade Study
200
180
160
140
Mass (kg)
120
100
Gas No Recycle
80
Gas 90% Recycle
60
Liquid No
Recycle
40
20
Liquid 90%
Recycle
0
0
2
4
6
8
Mission Duration (days)
10
12
14
Atmosphere Storage Volume Trade Study
0.35
0.3
Volume (m3)
0.25
0.2
0.15
Gas No Recycle
0.1
Gas 90% Recycle
Liquid No Recycle
0.05
Liquid 90% Recycle
0
0
2
4
6
8
Mission Duration (days)
10
12
14
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:
𝑘𝑔𝐶𝑂2
6 ℎ𝑜𝑢𝑟𝑠
1
×
× 4 𝑑𝑎𝑦𝑠 = 1 𝑘𝑔𝐶𝑂2
𝑑𝑎𝑦
24 ℎ𝑜𝑢𝑟𝑠
• 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
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:
1
𝑘𝑔𝐶𝑂2
𝑘𝑔𝐶𝑂2
× 3 𝑝𝑒𝑟𝑠𝑜𝑛𝑠 = 3
𝑝𝑒𝑟𝑠𝑜𝑛 − 𝑑𝑎𝑦
𝑑𝑎𝑦
• On each EVA day, crew is in cabin for 18 of 24
hours and thus produces:
3
𝑘𝑔𝐶𝑂2 18 ℎ𝑜𝑢𝑟𝑠
𝑘𝑔𝐶𝑂2
×
= 2.25
𝑑𝑎𝑦
24 ℎ𝑜𝑢𝑟𝑠
𝑑𝑎𝑦
• Total CO2 produced:
𝑘𝑔𝐶𝑂
9 𝑛𝑜𝑛 𝐸𝑉𝐴 𝑑𝑎𝑦𝑠 × 3 𝑛𝑜𝑛−𝐸𝑉𝐴2𝑑𝑎𝑦 + 4 EVA days × 2.25
𝑘𝑔𝐶𝑂2
𝑑𝑎𝑦
= 𝟑𝟔 𝒌𝒈𝑪𝑶𝟐
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
CO2 Scrubbing Trade Study
120
100
Mass (kg)
80
LiOH
60
Ca(OH)2
4BMS
40
20
0
0
2
4
6
8
10
Mission Duration (days)
12
14
Cabin CO2 Scrubbing Trade Study Results
LiOH (kg)
75.24
Ca(OH)2 (kg)
109.8
4BMS (kg)
90
• 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
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.
2.
3.
4.
Water in the sublimator extracts heat from the warm air
Water seeps through the pores of nickel plates, the opposite ends of
which are exposed to the vacuum of space
The water forms a layer of ice on the surface of the plate and
sublimes
The air is chilled via this process of heat extraction and is then
recirculated into the cabin
Cabin Atmosphere Conditioning Summary
Porous Plate
Sublimator
Pressurized
Cabin
Air
4BMS
Vaporizer
LOX
LN2
Fiberglass
Dust Filters
CO2
H2O
Vacuum
Unpressurized Storage
A
B
C
E
F
G
I
D
A.
B.
C.
D.
E.
H
F.
G.
H.
I.
Vaporizer
N2 Tank
O2 Tank
Propellant Tank
Vapor Compression
Distillation Unit
Multifiltration Unit
Four Bed Molecular Sieve
Porous Plate Sublimator
Particulate Filtration Unit
Water Required
Use
Amount of Water Required
Water 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
167.87 kg
(for 3 people, 13 days)
Water Required (cont.)
Use
Amount of Water Required
Hygiene Water
2.84 kg/person-day
Total Hygiene Water 110.76 kg
(for 3 people, 13 days)
Use
Hygiene Water
Potable Water
Total
Total Water Required (kg)
110.76
167.87
273.63
Water Recycling
System
Multifiltration
Distillation
Both
Mass (kg)
2.2
63
65
Volume (m3)
0.01
0.32
0.33
Vapor Compression Distillation was chosen because it is lowmass and low-wattage, while remaining within the volume
constraints. Numbers shown are scaled back to accommodate
the maximum water load on the system.
Water Required for Various Recycling Schemes
300
250
200
None
Mass (kg)
Hygiene
Atmospheric
150
Urine
Hygiene + Atmospheric
Hygiene + Urine
Atmospheric+ Urine
100
Hygiene, Atmospheric + Urine
50
0
1
2
3
4
5
6
7
Day
8
9
10
11
12
13
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
Radiation Exposure vs. Aluminum Areal Density
0.58
Solar Maximum Radiation Exposure (Sv)
0.57
y = 0.6817x-0.08
R² = 0.9693
0.56
0.55
0.54
0.53
0.52
0.51
0.5
0
5
10
15
20
25
Areal Density (g/cm^2)
30
35
40
45
Floor Plans
Reclined Chair (Launch)
Stowed Chairs
• Chairs in neutral body posture on • Chairs in sitting position
the astronaut’s back
• Stowed chair footprint:
• Reclined Chair footprint:
• .914x.615 m
– 1.82 x .615 m
• Inclining the chairs recovers
.557 m2
Interior Views
NBP Chairs
Control Surface
Toilet
Unpressurized
Storage
Stowed
Spacesuits
CTS Bags
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 Table
Item
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
Total
Design margin
1311.5
12.57%
Power Requirements
Item
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/sg22finalrep
ortr.pdf
MMR Technologies “Introduction to Vacuum Pump Usage” http://www.mmrtech.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-CR168484, October 1953
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19820067073_1982067073.pdf