Orbiter
Environmental
Control and Life
Support System
Orbiter ECLSS
Basic Life Support Needs
•Pressurized gas environment
•Oxygen supply
•CO2 removal
•Comfortable temperature range
•Comfortable humidity range
•Pure water supply
•Adequate nutrition
•Waste removal
Basic Life Support
Human Metabolism
Requirements
kg
Waste
kg
Oxygen
0.84
Carbon dioxide
1.00
Food solids
0.62
Respiration & perspiration water
2.28
Water in food
1.15
Urine water
1.50
Food preparation water
0.76
Feces water
0.09
Drinking water
1.62
Sweat solids
0.02
Urine solids
0.06
Feces solids
0.03
(water subtotal)
3.87
(water subtotal)
3.53
Total mass
4.99
4.98
Orbiter ECLSS – Basic Life Support Functions
Orbiter’s life support functions can support a crew of 7 for a
typical mission of 10-14 days
– In emergencies as many as 10 crewmembers
The Orbiter can also support missions up to three weeks by
carrying additional O2, N2 consumables, and expanded CO2
removal
– This addition is called the Extended Duration Orbiter (EDO)
package
Crew cabin environment is maintained within specific
temperature and humidity limits
– Additional limits are placed on carbon dioxide and toxic gas
levels
The active thermal control for the crew cabin is a combined
internal/external system
– Heat removal is also provided for the Orbiter's onboard
electrical and avionics systems
Orbiter ECLSS Subsystems
1. Cabin Atmosphere
–
–
–
Air Revitalization System (ARS)
Atmosphere Revitalization Pressure Control System (ARPCS)
Airlock Support System
2. Active Thermal Control
–
–
Active Thermal Control System (ATCS)
Water Coolant Loop System (WCLS)
3. Food
–
Food Supply and Management System
4. Water supply and Wastewater system
–
–
Water supply and purification
Waste water storage and disposal
5. Waste Management
–
Waste Collection System (WCS)
6. Smoke Detection and Fire Suppression
7. Space Suits and EVA
8. Airlock
Orbiter ECLSS Schematic
Orbiter ECLSS Layout
1. Cabin Atmosphere
Orbiter ECLSS - Crew Module
Crew module has a total pressurized volume of 65.9
m3 (2,325 ft3)
Additional pressurized areas in the cabin area are
storage lockers, pressurized equipment areas, and
the airlock
The airlock provides an additional 4.3 m3 (150 ft3) of
pressurized volume
Cabin pressurization is controlled by the
Atmosphere revitalization Pressure Control System
– Maintained at one atmosphere (14.7 psi), except
for EVA operations
Orbiter ECLSS - Crew Module
Crew module environment
Relative humidity
30 - 75%
Temperature
65 - 80oF
Oxygen partial pressure (PPO2)
2.29 - 3.45 psi
Crew cabin air flow
330 ft3/min
7 min complete air exchange period
Orbiter ECLSS - Historical Habitation Volumes (NASA)
1000
Skylab ISS
100
Mir
Salyut 7
Total
Pressurized
Volume
(m3/crew)
Apollo
10
LEM
Mercury
STS
Apollo
CM
Soyuz
Vostok
1
Gemini
Voskhod
0.1
1
10
Mission Duration (days)
100
1000
Orbiter ECLSS - Orbiter Atmosphere
Air Revitalization System (ARS)
Resupplies O2 and N2, and removes CO2,
water, and contaminants
Orbiter ECLSS - Orbiter Atmosphere
Air Revitalization System (ARS)
The Orbiter's air revitalization system supplies and
recirculates the O2 + N2 atmosphere components
Controls water vapor (relative humidity) and heat
within the cabin, airlock and space suits
ARS also monitors and removes CO2 and other toxic
gases
Filters airborne particles
Orbiter ECLSS - Cabin Air System
Orbiter ECLSS - Orbiter Atmosphere
Cabin Air Revitalization
Five cabin air revitalization loops are used
for cooling, ventilating, and supplying air to
the Orbiter's cabin
Individual loops pass directly or indirectly
through the cabin air system
Air revitalization loops
– Crew cabin (1)
– Avionics bays (3)
– Inertial Measurement Units (1)
Orbiter ECLSS - Orbiter Atmosphere
Crew cabin air loop
The single crew cabin air loop is designed to circulate air through
the air revitalization components in the cabin air system.
Responsible for removing:
Heat
– Removed by cabin air loop heat exchanger
Moisture
– Slurper bar in heat exchanger collects moisture which is pulled
into dual centrifugal water separators
– Removes approximately 4 lb/hr of H2O for typical crew
– Routed to the wastewater tank
Odors and trace contaminants
– Removed by activated charcoal filter located in the cabin air
system
Orbiter ECLSS - IMU Air Fan
Orbiter ECLSS - Orbiter Atmosphere
Crew cabin air loop used to remove:
CO2
– Cabin air circulated through two lithium hydroxide
(LiOH) canisters in the cabin air system
– Lithium hydroxide is used because is the lightest
hydroxide available, and is the least soluble
– Approximately 120 lb/hr flows to each of two
lithium hydroxide canisters
– Each canister is rated at 48 man-hours
– Up to 30 spare canisters are stored under the mid
deck floor
Orbiter ECLSS - Orbiter Atmosphere
Crew cabin air loop used to remove:
CO
– Ambient Temperature Catalytic Oxidizer (ATCO)
unit located downstream from the cabin heat
exchanger transforms CO to CO2 by catalytic
oxidation on a platinum-carbon surface
– Process combines CO with O2 which forms CO2
which is then removed by the LiOH canisters
Particles and debris
– Removed by 300 micron filter in the fan
circulation units
Orbiter ECLSS - Orbiter Atmosphere
CO2 removal
Lithium hydroxide (LiOH) – canister form
CO2 removal in the Orbiter's crew cabin employs
traditional lithium hydroxide canisters
Used in all manned vehicles with the exception
of the space stations (Skylab, Salyut, Mir, ISS)
Orbiter cabin air is circulated through two LiOH
canisters
Orbiter ECLSS - Cabin Fan and LiOH Housing
Orbiter ECLSS - Orbiter Atmosphere
CO2 removal - Lithium hydroxide
Changed out regularly since CO2 cannot be
removed from the canisters
– The lithium carbonate and water products are
stable, but incapable of further CO2
absorption
Sufficient LiOH must be carried for the entire
mission, plus additional canisters for possible
mission extension and emergency reserve
Orbiter ECLSS - Orbiter Atmosphere
LiOH canisters are an
inexpensive solution to
CO2 removal but create
a weight penalty since
they retain their original
mass and the absorbed
mass of CO2 and some
of the respiration water
Canisters are returned
to Earth for
disposal/refurbishment
Orbiter ECLSS - LiOH Replacement
Orbiter ECLSS - Orbiter Atmosphere
CO2 removal
Regenerable Carbon Dioxide Removal System
(RCRS)
RCRS is used for missions longer than 16 days on
orbit, or for 12 to 16 day duration missions for a
crew of up to seven astronauts
Carbon dioxide removal is accomplished by
passing cabin air through a regenerable CO2
removal system instead of the lithium hydroxide
canisters
Orbiter ECLSS - Orbiter Atmosphere
CO2 removal - RCRS
The regenerable system saves weight since the CO2
and water are dumped overboard instead of
absorbed in the LiOH canisters and stored for return
to Earth
CO2 removal in the RCRS takes place in one of two
identical solid amine resin beds
– Commonly called swing beds because of their alternating
use as an absorber then the desorbtion cycle
– Resin combines with CO2 and water vapor in the air to form
a hydrated amine
– Water is required for the process since dry amine cannot
react with the carbon dioxide directly
RCRS
Orbiter ECLSS - Orbiter Atmosphere
CO2 removal - RCRS
While one bed adsorbs carbon dioxide, the other
bed desorbs/regenerates using a bed heater while
being exposed to space vacuum
– Process removes both the CO2 and the water
from the amine granules
– Need for a vacuum vent prevents the use of the
RCRS during ascent or entry
– LiOH canisters are therefore included on the
RCRS flights
RCRS Unit – Hamilton Sunstrand
Orbiter ECLSS - Orbiter Atmosphere
CO2 removal - RCRS
The adsorption-regeneration process in the RCRS
runs continuously with the beds automatically
swapped every 13 minutes
– Full cycle is made up of two 13 minute cycles
An RCRS configured vehicle uses a single LiOH
canister for launch and another for entry
– An activated charcoal canister in the other CO2
absorber slot removes odors
– Changed-out mid mission on 10+ day flights
Orbiter ECLSS - Orbiter Atmosphere
Atmosphere Revitalization Pressure
Control System (ARPCS)
Controls cabin pressure
Orbiter ECLSS - Orbiter Atmosphere
Cabin pressurization
The Orbiter cabin pressure is maintained at 14.7
±0.2 psia (or 10.5 psia for EVA) with two independent
pressurization systems designated PCS 1 and PCS
2
– Total cabin pressure is regulated separately with
the oxygen and nitrogen supplies, with oxygen
the primary component
– Nitrogen is regulated to make up the difference
between the 2.95 psi oxygen pressure and the
14.7 psi total pressure
– The actual oxygen pressure range limit
maintained by the ARPCS is 2.95-3.45 psia
Orbiter ECLSS - Orbiter Atmosphere
Cabin pressurization
Crew respiration O2 consumption is approximately
0.8 kg (1.76 lb) per day
– Total consumption for crew respiration and cabin loss is
typically 4.1 kg (9 lb) per day
Oxygen is fed to the cabin from the cryogenic
storage tanks that also serve as reactant storage for
the fuel cells
– Oxygen is supplied from the cryogenic tanks through a
restrictor and heated with a small heat exchanger on the
Freon coolant loop before entering the crew cabin
– Maximum flow rate for cabin oxygen is 11.4 kg (25 lb) per
hour is available in case of rapid cabin depressurization
– Nominal ECLSS budget for the crew oxygen is 0.91 kg (2.08
lb) per man-day
Orbiter ECLSS - Orbiter Atmosphere
Cabin pressurization
Nitrogen is supplied from pressurized gas
storage tanks located in the payload bay
– Consumption rate of approximately 3.5 kg
(7.7 lb) per day from cabin loss and
venting
– Regulation of the nitrogen gas by the
ARPCS provides the remainder of the total
cabin pressure of 14.7 psia
– Nitrogen gas is also used to pressurize the
water storage tanks for positive feed in
microgravity
Orbiter ECLSS - Orbiter Atmosphere
Cabin pressurization
During on-orbit operations the crew cabin is
supplied with a single PCS system for N2 and O2
– Second PCS system configured for backup
– Both PCS systems are used during launch and
reentry
– Auxiliary tank of pressurized oxygen is also
available for contingency crew cabin supply
Orbiter ECLSS - Orbiter Atmosphere
A cabin vent valve is included in the pressurization
system to equalize the cabin pressure with ambient
pressure
– While on the launch pad
– In extreme emergencies
– On orbit or during reentry for contingencies such
as a cabin fire or to vent the cabin atmosphere to
space through the payload bay
Orbiter ECLSS - Orbiter Atmosphere
Cabin pressure limitations
Atmosphere monitored by caution and warning
system for:
– Cabin pressure below 14.0 psia or above 15.4
psia
– Partial pressure of oxygen (PPO2) below 2.8 psia
or above 3.6 psia
– Oxygen flow rate above 45 lb/hr
– Nitrogen flow rate above 5 lb/hr
– Cabin pressure change greater than 0.05 psi/min
Orbiter ECLSS - Caution and Warning Panel
Orbiter ECLSS - Orbiter Atmosphere
Cabin pressure limitations
Cabin over-pressure relief valve is set for 16 psia
Positive and negative pressure relief valves in the
ARPCS are used to protect the structural integrity
of the cabin from over- and under-pressurization
– Over-pressure relief valve opens at 15.5 psid
(differential) with full flow at 16.0 psid
– Under-pressure relief valve opens at -0.2 psid
(ambient pressure greater than cabin pressure)
Orbiter ECLSS - Orbiter Atmosphere
Orbiter cabin pressurization – EVA
The Orbiter's crew cabin pressurization maintains a
14.7 psia atmosphere except for EVA and EVA
preparation
During EVA preparation the cabin pressure is
reduced to 10.2 psia to minimize the risk of
decompression sickness (bends) for the EVA crew
– Standard protocol calls for EVA crew members to
prebreathe pure O2 before EVA to help flush N2
form their body tissue
Orbiter ECLSS - Orbiter Atmosphere
Orbiter cabin pressurization – EVA
Three protocols (options) are available for the mission
planners and crew for EVA prebreathing routines to
reduce nitrogen in the blood of the EVA astronauts
Option 1
60-minute initial O2 prebreathe on launch and entry
suit helmet
12 hours at 10.2 psia cabin pressure
75-minute final O2 prebreathe in EVA suit
Orbiter ECLSS - Orbiter Atmosphere
Orbiter cabin pressurization – EVA
Option 2
60-minute initial O2 prebreathe on launch and
entry suit helmet
24 hours at 10.2 psia cabin pressure
40-minute final O2 prebreathe in EVA suit
Orbiter ECLSS - Orbiter Atmosphere
Orbiter cabin pressurization – EVA
Option 3
4-hour O2 prebreathe in EVA suit
For scheduled EVAs, option 1 or 2 are used to minimize
the in-suit O2 prebreathe just prior to the EVA
PPO2 levels must be controlled manually during 10.2
psia cabin operations
2. Orbiter Active Thermal
Control System (ATCS)
Orbiter ECLSS - Active Thermal Control System
The Active Thermal Control System removes heat
from the interior of the Orbiter during all phases of
the flight, from pre-launch to post-landing
Operational environment extremes in temperature
and temperature require three independent heat
removal subsystems (sinks)
– Radiator panels
– Water flash evaporators
– Ammonia boilers
Orbiter ECLSS - Active Thermal Control System
Orbiter ECLSS - Active Thermal Control System
The Orbiter’s Active Thermal Control System uses a
total of four coolant loops to remove heat from the
interior of the three fuselage sections
Dual-redundant interior water loops
Dual-redundant exterior Freon loops
Heat passage from the interior loop to the exterior
loop is through a highly conductive heat exchanger
Orbiter ECLSS - Active Thermal Control System
Heat from the
interior of the
Orbiter is
transferred to
these
subsystems
using dual
independent
water and Freon
cooling loops
Ground Service
Equipment is
used during
prelaunch and
post-landing to
remove heat
through the T-0
umbilical panel
on the aft
fuselage
Orbiter ECLSS - Active Thermal Control System
Two dual-redundant cooling loops used for safe,
effective heat removal
Water coolant loop (cabin)
Two separate internal water coolant loop systems
condition the crew cabin by transferring heat from
the crew cabin, avionics bays and IMUs
– Heat is transferred to the dual external Freon
coolant loops through a heat exchanger called
the interchanger
Orbiter ECLSS - Active Thermal Control System
Water coolant loop
Two internal water coolant loops are identical, except that
loop 1 has two water pumps and water loop 2 has one
The separate water coolant loops are laid out side-by-side
and can operate at the same time
– Only one is active at any given time
– Loop 2 with a single pump is normally the active loop
The three water pumps are located in the ECLSS bay
below the forward lockers
– ATCS pumps are powered by three-phase, 115-volt ac
motors
Orbiter ECLSS - ATCS Water Loops
Orbiter ECLSS - ATCS Water Loops
Orbiter ECLSS - Active Thermal Control System
Freon Cooling System (FCS) – external loop
Freon - chlorofluorocarbon and
hydrochlorofluorocarbon refrigerants used in air
conditioning and refrigeration systems
– DuPont products
– Odorless
– Colorless
– Nonflammable
– Noncorrosive
– High thermal conductivity
– High stability
– Environmental hazard because of its ability to
break down ozone in the upper atmosphere
Orbiter ECLSS - Freon Cooling System
Two independent Freon-21 coolant loops designated
A and B are integrated into each Orbiter
Transfers heat from the Orbiter's internal water
loops and external sources to the heat sinks
– Freon was chosen for its efficient heat transfer,
but poses a toxic gas hazard to the crew if it were
to leak into the cabin module
Orbiter ECLSS - Freon Cooling System
Dual-redundant Freon-21 systems provide system
redundancy for the Orbiter's external cooling loop
– Each of the two Freon loops has a pump package
consisting of two pumps and an accumulator
used to reduce pressure spikes at pump startup
and shutdown
– One pump in each loop is active at all times
– A separate set of Freon loops (using Freon-40)
transfers heat from the three fuel cells to the
Freon-21 outer loops via the fuel cell heat
exchanger
Orbiter ECLSS - ATCS Water Loops
Orbiter ECLSS - Active Thermal Control System
Freon Cooling System (FCS)
Avionics and electronics heat removal is
accomplished with conductive cold plate networks
for increased heat transfer efficiently
– Forced-air cooling is used for larger
electronics/avionics heat loads including the
IMUs, TACAN, MSBLS, and GPCs
Liquid-to-liquid heat exchangers are used to transfer
heat from external cooling loops and cold plates to
the external Freon 21 cooling loop pair
– The two internal water cooling loops are
connected to the outer Freon 21 cooling loop
through the water/Freon interchanger (heat
exchanger)
Orbiter ECLSS - ATCS Freon Loops
ATCS Freon Loop Pump Package
Orbiter ECLSS - Heat Removal
Four heat sink systems are used on the Orbiter
for rejecting internal heat to
space/atmosphere/ground equipment
1. Radiator Panels
2. Ammonia Boiler System (ABS)
3. Flash (water) Evaporator System (FES)
4. Ground Service Equipment connections
Heat is carried to these sinks via the dual
internal water loops, through the
water/Freon interchanger, then to the dual
external Freon loops
Orbiter ECLSS - Heat Removal
Heat removal (sinks)
1. Radiator Panels
Radiation of heat to space from the Orbiter uses
three panels on each of the payload bay doors in
the normal configuration
– Two of four radiator panels on the forward
section of the payload bay doors can be
extended (deployed) for increased heat rejection
– Individual mission requirements determine if the
forward radiators are deployed based on the heat
load
– The third and fourth radiator panels are fixed to
the aft underside of the aft right and left payload
bay doors and are not deployable
Orbiter ECLSS - ATCS Radiator Panels
Orbiter ECLSS - Heat Removal
Radiator panels – Construction
Radiator panels are composed of aluminum honeycomb sheet
– Payload bay doors are composed of composite materials
Cooling tubes that circulate the Freon 21 are located near the
radiator surface
Combined surface area of the radiator panels is 111 m3 (1,195
ft3)
The maximum heat rejection capability of the radiator system is
61,100 Btu per hour
Cold soaking the Freon that circulates in the radiators by
decreasing the temperature before reentry is used as a heat
sink during the later stages of reentry
ATCS Radiator Panels
Orbiter ECLSS - Heat Removal
2. Ammonia Boiler System (ABS)
Ammonia boiler extracts heat from the cooling loop by
the evaporation of ammonia
Because ammonia has a boiling point lower than water,
the ammonia evaporator is useful for primary cooling at
higher ambient pressures
– Primarily from reentry to landing if the radiators have
not been cold-soaked
– If radiator cooling is used during entry, the ammonia
system is activated post-landing when the radiator
outlet temperatures reach 12.8oC (55oF)
– The ammonia boiler is also used post-landing until
the Orbiter is connected to a portable GSE heat sink
Orbiter ECLSS - Heat Removal
Each of the two Ammonia Boiler Systems
located in the aft fuselage consists of:
– Boiler/evaporator
– Storage tank
– Isolation valve
– Overboard relief valve
– Two control valves
– Controller
– Three temperature sensors
– Pressure sensor
– Feedline to the boiler
Orbiter ECLSS - Heat Removal
Ammonia Boiler System (ABS)
ABS heat exchanger is a single-pass ammonia and a
two pass flow-through Freon coolant loop
Ammonia flows over the hot Freon coolant lines in
the evaporator/boiler and is vaporized
Orbiter ECLSS - Heat Removal
Ammonia Boiler System (ABS)
Heat and boiler exhaust is vented overboard in the
upper aft fuselage of the Orbiter, next to the bottom
right side of the vertical tail
ABS contains a single boiler that is fed by two
independent ammonia supply subsystems
Maximum heat rejection for the ABS is 113,200
Btu/hr
Orbiter ECLSS - Heat Removal
3. Flash Evaporator System (FES)
The FES is used to remove heat from the Orbiter's
Freon-21 loops by circulating the heated Freon
through the FES evaporation radiator sprayed with
potable water
Cooling comes from the heat of vaporization of the
evaporating water vented to space
– An efficient cooling process until atmospheric pressure
becomes significant
– Hence are used during ascent while above 140,000 feet
– FES can also be used to supplement the radiator heat sink
on orbit
– Can also be used during deorbit and entry above
approximately 100,000 feet
Orbiter ECLSS - Flash Evaporator System
Orbiter ECLSS - Heat Removal
Flash Evaporator System (FES)
Cold-soaking is normally used for the Orbiter's
cooling during reentry and descent
FES is housed in the aft fuselage
Two evaporation evaporators/boilers are used in the
FES
– High-load evaporator has a higher cooling capacity than the
topping evaporator
Has only one overboard vent on the left side of the vehicle
– Lower-capacity topping evaporator
Has two vents that discharge steam equally to the left and right
sides of the Orbiter for reactive force symmetry (nonpropulsive)
Flash Evaporator System
Orbiter ECLSS - Heat Removal
Flash Evaporator System (FES)
FES characteristics include:
1,000 Btu per hour per lb of water consumed
Maximum heat rejection is 148,000 Btu/hr using both
topping and high-load evaporators
Used from 125 sec after liftoff until payload bay
doors are opened on orbit
Orbiter ECLSS - Heat Removal
Flash Evaporator System (FES)
Used from payload bay closure until 100,000' altitude
Water supplied by potable water storage tanks A & B
– Potable water is used to avoid buildup of deposits
on the interior of the evaporator
Orbiter ECLSS - ATCS GSE
4. Ground support heat
exchangers
Ground support equipment is
used to remove heat from the
Orbiter during ground
operations
– Post-landing & tow-in
– Orbiter Processing
Facility
– Vehicle Assembly
Building
– Rollout on Crawler to
launch pad
– Launch pad
Portable GSE cooler used for
post-landing is shown being
attached to the Orbiter’s T-0
panel
3. ECLSS - Food
Orbiter ECLSS - Food
Foods supplied on STS missions are categorized as three
basic types
– Menu
Menu foods are stocked for three meals per day
Provides an average of 2,700 calories for each
crewmember per day
– Pantry
Snacks and beverages
Can be interchanged with planned menu items
Make up a 2-day contingency supply
Furnishes 2,100 calories per crewmember per day
– Fresh
Include perishable items such as fruits and
vegetables
Orbiter ECLSS - Food
Foods with a longer shelf-life are classified as:
– Rehydratable (soups, casseroles, appetizers,
breakfast foods)
– Thermostabilized (meats, vegetables, fish, fruit)
– Irradiated (meats)
– Intermediate-moisture (dried fruit, dried meat)
– Natural-form (nuts, granola bars, cookies)
Orbiter ECLSS - Food
Astronauts choose their meals before the missions far
enough in advance for preparation, refrigeration, and
storage on the Orbiter
Vitamins and minerals are included in the astronaut's
individual diets according to NASA's nutritional
guidelines and with the assistance of dietitians
Orbiter ECLSS - Food
Galley
A galley is provided for crew meals in the mid deck
section of the Orbiter that provides:
– Oven
– Rehydration unit
– Cold and hot water
– Storage for utensils, condiments and
implements
– Cleanup equipment & storage
Orbiter ECLSS - Food
Galley
Traditional liquid condiments like ketchup, mustard,
mayonnaise, and hot sauce are provided in familiar
packets
Powdered condiments like salt, pepper, and sugar
are maintained in liquid form in dispensers to keep
the contents from floating throughout the cabin
Beverages are stored in collapsible containers and
consumed using straws
Orbiter ECLSS - Galley
Orbiter ECLSS - Food
Galley
The galley oven and rehydration station is capable of
preparing meals for the entire crew at the same time
The three one-hour daily meal periods include
cleanup, and waste and packaging storage, usually in
the Waste Collection System
Breakfast, lunch and dinner are scheduled as close
to the usual meal times as possible
Orbiter ECLSS - Galley
Orbiter ECLSS - Menu
Guide
Orbiter ECLSS - Food
Individual meals are selected by each
crewmember for the entire mission
Stored in middeck lockers
Color coded
4. Water and
Wastewater System
Orbiter ECLSS - Water & Wastewater
Water onboard the Orbiter is generated by the fuel
cells as potable water
Used for crew consumption, crew hygiene, and for the
flash evaporator cooling system
– Excess water from fuel cells is normally dumped
overboard, along with excess waste water
– Supply water dump can also be routed through the
FES as coolant if needed
– Excess water can also be transferred to the
International Space Station when docked
Orbiter ECLSS - Water & Wastewater
Water is stored in five 104 liter (27.5 gal, 165 lb) tanks
– Designated A, B, C, and D, and one waste water tank
– Tank A is reserved for potable water for crew
consumption and the first to be filled from the fuel cell
supply
– B, C, and D are used for excess water storage and are
filled in sequence after Tank A
All four of the water supply tanks can be used for the
Flash Evaporator System
– Tanks B, C, and D are normally used for that purpose
All water tanks including waste water tank are pressurized
with nitrogen gas
– Drained by a bellows system
Orbiter ECLSS - Water Tank (Mounted as Pair)
Orbiter ECLSS - Water & Wastewater
Water from the supply water tanks is also used to
service the water supply for EMU suits in the airlock
Fuel cell water production has a maximum production
of 15.5 l/hr (4.1 gal/hr)
– Equivalent to 0.37 kg (0.81 lb) of water per kW-hr
Water lines from the fuel cells that are located in the
payload bay to the tanks located in the forward
fuselage are heated to prevent freezing on orbit
– Water dump lines are also heated, as are the dual
water dump nozzles
Orbiter ECLSS - Water Dump Ports & Heaters
Orbiter ECLSS - Water & Wastewater
Hydrogen separators remove excess hydrogen from
the power production process in the fuel cells
before being routed to the water supply tanks
Supply water is passed through a microbial filter
before entering tank A
– Microbial filter adds iodine compound to the
water that enters tank A to prevent microbial
growth in the water supply system
Orbiter ECLSS - Water & Wastewater
Tank A water is filtered before being sent to the
galley for chilled water (45-55oF) and heated water
(155-165oF) supply
Inlet valves and outlet valves on the supply water
tanks allow selective fill and selective water dump
– Up to 210 lb of water can be dumped at a time
76% of the water in tank A must be maintained for
minimum crew requirements
Orbiter ECLSS - Water & Wastewater
Orbiter potable water purification
0.5 ppm iodine solution added to tank A inlet
Microbial filter in supply line removes small particles
and microbes
pH sensors monitor water purity
Orbiter ECLSS - Water & Wastewater
Hydrogen separators remove 85% of hydrogen-rich
fuel cell water
– Line to Tank A passes through two hydrogen
separators consisting of a matrix of silver
palladium tubes which have an affinity for
hydrogen
85% of hydrogen is removed then dumped
overboard
Orbiter ECLSS - Water & Wastewater
Orbiter potable water purification
The waste water tank drain is not used in flight
– Waste water inlet line also acts as the outlet line
for dumping excess waste water overboard
– A separate waste water dump line and nozzle is
available, with a crossover for use by the supply
tanks
– A collapsible waste water bag is carried on the
Orbiter in case the waste water dump nozzle is
blocked
5. Waste Collection
System
Orbiter ECLSS - Waste Collection System
The Orbiter's waste collection system is used
primarily to collect crew fecal and urine waste in a
zero gravity environment
WCS base is the Orbiter commode
WCS is used to: process crew cabin and EMU
condensate for waste water storage
Waste collection unit also routes wet trash gas for
dumping overboard, transfers condensate water to
the waste water tank
– Facilitates condensate water overboard dumping, if
necessary
Orbiter ECLSS - Waste Collection System
The Orbiter's WCS is
contained in a module
that contains the
waste tank, commode,
and the waste
management (wet and
dry trash)
compartment
Orbiter ECLSS - Waste Collection System
Major components of the WCS include:
Waste management compartment and privacy curtains
Commode
– Bag liner used for solid fecal waste storage
– Vacuum exposure of bag liner is used for drying when not in use
Urinal
– Separate male and female adapters
– Processed for storage in waste water tank
Fan separators
– Air flow transport for liquids in waste collection system
Odor and bacteria filter
– Separated air filtered and mixed with cabin air
– Vacuum vent disconnect
– Allows ARS waste water to be dumped overboard
Waste collection controls
Orbiter ECLSS - Waste Collection System
Orbiter ECLSS
Waste Collection System
6. Fire Detection and
Suppression System
Orbiter ECLSS - Smoke Detection and Suppression System
Smoke detection and fire suppression components on
the Orbiter are located in the crew cabin and the
avionics bays
Ionization detectors that sense smoke particles will
trigger alarms at set concentration levels, or at
concentration change limits
Readouts of the smoke detectors are shown on the
performance monitoring CRTs, as well as on lighted
panels and on the caution and warning illuminated
panels
Orbiter ECLSS - Smoke Detection and Suppression System
Two groups of smoke sensors identified as A
and B provide information on the general
location
– Specific ionization detector can be identified on the
CRTs
Group A detectors located in the ECLSS cabin
fan outlet and left return duct, as well as one
each in the avionics bays 1, 2, and 3
Group B are located in the right cabin return
duct and the three avionics bays
Orbiter ECLSS - Smoke Detection and Suppression System
Fire suppression on the Orbiter is divided into two
areas with two separate chemicals – avionics
extinguishers and crew cabin extinguishers
– Freon-1301 (bromotrifluoromethane) extinguisher bottles
used for the three avionics bays
– Three portable extinguishers in the cabin are charged with
Halon-1301 (monobromotrifluoromethane) for the crew
cabin
Halon-1301 is chosen for its effectiveness in controlling
smoke, heat, oxygen depletion, and its ability to reduce
pyrolysis products such as carbon monoxide
Avionics bay extinguishers are fired by switches on
the L1 panel
Halon-1301 portable extinguishers are discharged
manually
7. Spacesuits and EVA
Orbiter EVA
Spacewalks, or extravehicular activity (EVA), requires
a self-contained, pressurized space suit that
provides the same essential life support functions
as the crew vehicle
Space suit life support functions include:
Oxygen supply
Carbon dioxide removal
Thermal control
Odor and trace gas removal
Water supply
Food
Waste removal
Orbiter EVA
The crew space suit, called the
Extravehicular Mobility Unit (EMU), supplies
life support basics, and:
–
–
–
–
–
Rechargeable battery electrical power
Duplex UHF communications
Biological and instrument telemetry
Instrumentation
Caution and Warning (C/W) electronics
Orbiter EMU
The Orbiter EMU is divided into three main parts
– Hard Upper Torso (HUT)
– Lower Torso assembly (LTA)
– Portable Life Support System (PLSS)
Many of the features and subsystems on the EMU
have evolved from the earlier NASA space suits,
including the self-contained PLSS, and the
sublimator cooling unit that came from the Apolloera suit
Orbiter EMU
Typically, two EMUs are available for
missions that require EVA
EMUs are tailored to the astronaut and
stored in the airlock except when in use on
EVA
Design lifetime of the EMU is 15 years
Orbiter EMU
Orbiter EMU
Pure oxygen is used for suit pressurization which
is maintained at 4 psid
Oxygen capacity of the EMU is seven hours, with a
30 minute emergency reserve
Pressurized O2 bottles contained in the PLSS
include
– 1.2 lb @ 8,500 psi
– Secondary oxygen pack with 2.6 lb @ 6,000 psi
Orbiter EMU
A replaceable lithium hydroxide cartridge is
used for carbon dioxide removal
Odor and trace gases are removed with an
activated charcoal filter placed in the
air/oxygen circulation line
– Powered by a circulation fan
Orbiter EMU
Major components
Liquid Cooling and Ventilation Garment (LCVG)
The LCVG is worn by the astronauts as an
undergarment to remove excess body heat
Heat removed via a network of tubes that
distributes oxygen and cool water throughout
the garment
Water pump circulates the water through a
thermal control valve assembly and
sublimator
Orbiter EMU
– Sublimator allows the passage of the warm water
through channels in the porous block
– As the water seeps towards the outer surface, the
cold vacuum conditions in space freezes that
water
– Frozen water exposed to space sublimates, which
cools with an equivalent heat loss of both the heat
of vaporization and the heat of fusion
– Liquid water is not allowed to reach the surface
because of the ice formed in the outer block,
which cools the liquid water flowing through the
interior channels
Orbiter EMU Liquid Cooling and Ventilation Garment
Bruce McCandless
on STS-31 shown
entering the Lower
Torso Assembly and
wearing the Liquid
Cooling and
Ventilation Garment
Orbiter EMU
Hard Upper Torso (HUT)
The Hard Upper Torso is the single-piece EMU rigid
above-the-waist structure used to mount the space
suit attachments and components that are movable,
removable, or replaceable
– Includes the arms, gloves, helmet, lower torso,
PLSS, display and control module, and electrical
harness
– HUT arms contain a shoulder joint and elbow
joint, along with mobility bearings in the upper
arm and wrist
Orbiter EMU
Lower Torso Assembly (LTA)
The Lower Torso Assembly, roughly everything
on the space suit below the waist, is attached to
the Hard Upper Torso at the top and boots at the
bottom
LTA is composed of a number of layers that make
up the flexible pants, as well as hip, knee and
ankle joints
Orbiter EMU
Portable Life Support System (PLSS)
The PLSS is a fiberglass structure attached to the HUT
and used to mount the internal and external
components.
– Fiberglass construction
– Water storage bladder tanks (3)
10 lb capacity
– Air circulation fan
– Sublimator
– Contaminant control cartridge
LiOH for CO2 removal
Activated charcoal for odor & contaminant
removal
– Communications antenna
Orbiter EMU - PLSS
Orbiter EMU
The EMU also contains power,
communications, and life-support
essentials that include:
–
–
–
–
–
–
–
–
Communications carrier assembly
Two UHF transmitters
Three single channel receivers
Liquid cooling and ventilation garment
Urine collection device
Operational bioinstrumentation system
Display and control module
Silver-zinc battery electrical supply
Orbiter EMU
EMU-EVA life support duration
Total duration
EVA
Checkout/donning
Doffing
Reserve
7 hr
6 hr
15 min
15 min
30 min
An additional 30 minutes is available from secondary oxygen
supply if the primary system fails
Orbiter EMU - Power and Display Section
8. Airlock
Orbiter Airlock
The Orbiter's airlock assembly is used prepare two
astronauts for EVA
Provides for crew egress, and for their ingress in a
controlled-pressure, pure oxygen environment
Pressurized airlock chamber is located either in the
crew cabin mid deck, or in the payload bay,
depending on mission and payload requirements
The 4.3 m3 (150 ft3) cylindrical airlock chamber
includes two pressure hatches with windows, one on
the cabin side, and one on the payload bay side
Latch and gearbox assembly is placed on both sides
of both hatches to allow EVA and cabin crew access
to the airlock
Orbiter Airlock
Two complete EMUs are stored in the airlock, along with
a portable oxygen system
Handholds, footholds and seating are furnished in the
airlock for maneuvering in and out of the airlock
Service connections are also provided for
– Oxygen
– CO2 removal for airlock and suits
– Liquid-cooled garment water
– O2 recharge for suits
– Electrical power
– Airlock and suit communications
– Lighting
Orbiter Airlock
ECLSS Control Panel R1
ECLSS Control Panel R1
ECLSS Control Panel R1
References:
NASA ECLSS
NASA Food
Shuttle Crew Operations Manual - ECLSS, NASA
Shuttle Crew Operations Manual - Food, NASA
ECLSS 21002 - Environmental Control and Life Support System
Training Manual, Mission Operations Directorate, Space Flight
Training & Facility Operations, Shuttle Systems Training Branch,
NASA, June 1999