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Space Shuttle Life Support
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 1 of 33
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ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM
The environmental control and life support system (ECLSS) consists of
an atmospheric revitalization subsystem (ARS), water coolant loop sub-
system (WCLS), atmosphere revitalization pressure control subsystem (AR-
PCS), active thermal control subsystem (ATCS), food, water, and waste man-
agement subsystem (FWWS), and airlock support subsystem. These subsystems
interact to provide a habitable environment in the crew compartment for
the crew and passengers.
The ARS provides humidity, carbon dioxide, and carbon monoxide control
for the crew compartment, controls cabin temperature and ventilation, and
provides cooling to the flight deck avionics, cabin, and avionics bays.
The ARPCS controls cabin pressure and oxygen partial pressure, nitro-
gen pressurization of the potable and waste water tanks, and storage of ni-
trogen and emergency oxygen consumables.
The WCLS collects heat from the cabin atmosphere and electronics and
transfers it to the ATCS, which rejects it to space via water and Freon
coolant loops. The ATCS also removes and rejects waste heat from the fuel
cells, payload, and mid-body and aft-located electronic units, while pro-
viding heating of the hydraulic systems when needed.
Potable water is produced by the three fuel cells aboard the space-
craft and stored in tanks for crew consumption and personal hygiene; dur-
ing certain phases of the mission it is also used for cooling of the Freon
coolant loops. Waste water collected from the cabin heat exchanger is
stored in tanks along with crew member's waste water. Solid waste remains
in the waste management system until the orbiter is serviced on the
ground.
The orbiter crew compartment provides a life-sustaining environment
for a crew of four and has accommodations for four passengers. The crew
cabin volume with the airlock inside the mid deck of the crew compartment
is 66 cubic meters (2,325 cubic feet). If the airlock and the tunnel adapt-
er are outside in the payload bay area, the volume is 74 cubic meters (2,
625 cubic feet).
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 2 of 33
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ATMOSPHERIC REVITALIZATION CONTROL SUBSYSTEM
The ARS maintains a habitable environment for the crew and passengers
and a conditioned environment for the electronic avionics equipment locat-
ed inside the crew cabin. The ARS consists of the water coolant loops
(WCL), and the cabin air loops, and pressure control.
CABIN PRESSURE. The cabin is pressurized to 760 millimeters of mer-
cury (mmHg) +/-10 mmHg (14.7 +/-0.2 psia) and maintained at an average 80
percent nitrogen and 20 percent oxygen mixture by the ARS.
Oxygen partial pressure is maintained between 152 and 178 mmHg (2.95
and 3.45 psi), with sufficient nitrogen added to achieve the cabin total
pressure of 760 plus or minus 10 mmHg (14.7 +/-0.2 psia) for operational
orbiters and 750 +/-10 mmHg (14.5 +/-0.2 psia) for the development test
flights.
Oxygen is obtained from three sources: the primary and secondary power
reactant supercritical cryogenic oxygen storage supply system and an emer-
gency gaseous oxygen supply system. The supercritical cryogenic oxygen sup-
ply system is located in the lower portion of the mid fuselage and is also
utilized by the three power reactant fuel cells. The emergency gaseous ox-
ygen supply is located in the forward portion of the mid fuselage.
Nitrogen is obtained from the primary or secondary gaseous nitrogen
storage supply system located in the lower forward portion of the mid fuse-
lage. For normal orbital operations, one oxygen and nitrogen system is
used. For launch and entry, both the primary and secondary systems will be
used.
The heart of the ARS is a nitrogen/oxygen control panel and a supply
panel, oxygen partial pressure sensor, and crew compartment positive and
negative pressure relief valves.
Primary and secondary nitrogen are provided to the control panel from
the N2 storage tanks via the supply panel. The N2/O2 control panel se-
lects and regulates primary or secondary O2 and N2. There is also a cross-
over between the primary and secondary systems. The control panel can reg-
ulate the emergency gaseous oxygen supply and supply oxygen for airlock
support. The primary and secondary systems are used together during air-
lock repressurization.
The gaseous nitrogen primary and secondary storage tanks No. 1 and 2
and O2/N2 supply panel are located in the lower forward portion of the mid
fuselage. The N2 storage tanks are serviced to a nominal pressure of
153,240 mmHg (2,964 psia) at 26 degrees C (80 degrees F). The emergency ox-
ygen supply tank in the lower forward portion of the mid fuselage is ser-
viced to a nominal pressure of 126,150 mmHg (2,440 psia) at 26 degrees C
(80 degrees F) and stores 29.7 kilograms (67.6 pounds) of gaseous oxygen
to provide high flow along with gaseous nitrogen for emergency entry in
the event of a crew compartment puncture. The emergency supply maintains
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 3 of 33
---------------------------------------------------------------------------
the cabin at 414 mmHg (8 psi) and oxygen partial pressure at 103.5 mmHg (2
psia).
The O2 and N2 systems provide makeup gas for oxygen consumption by the
crew and passengers. Four crew members us an average of 0.79 kilograms
(1.76 pounds) of O2 per person per day. Up to 3.49 kilograms (7.7 lbs) of
nitrogen and 4 kilograms (9 pounds) of oxygen are expected to be used per
day for normal loss of crew cabin air to space and metabolic usage. The
O2 and N2 also provides for repressurization of the airlock and pressuriza-
tion of the potable and waste water tanks. The tanks are pressurized to
879 mmHg (17 psi).
The supercritical cryogenic oxygen primary and secondary storage sup-
ply systems are controlled individually by ATM (atmospheric) PRESS (pres-
sure) CONTROL O2 (oxygen) SYS 1 and 2 SUPPLY switches on flight deck dis-
play and control Panel L2 (when switch and display nomenclature is printed
in all caps, it indicates that it is the exact way it appears on the dis-
play and control panel). When a switch is positioned to OPEN, oxygen sup-
ply system is directed to a heat exchanger in Freon-21 coolant loop system
No. 1 (for system No. 1 oxygen) and coolant loop system No. 2 (for system
No. 2 oxygen) which warms the supercritical cryogenic oxygen supply to the
O2 regulator of that system. When the switch is closed, the oxygen stor-
age supply system is isolated from the O2 regulator. An indicator above
the switches will show when a valve is open or closed.
The oxygen supply system is directed to an O2 REG (regulator) INLET
manual valve when the respective ATM PRESS CONTROL O2 SYS SUPPLY valve is
open. The manual O2 REG INLET valve of that system, when open, directs
that O2 supply to its O2 regulator. The O2 regulator in each system reduc-
es the oxygen supply source pressure to 5,175 millimeters of mercury
(mmHg) (100 psi) with a minimum flow rate capability of 34 kilograms (75
pounds) per hour. Each regulator is a two-stage regulator with the second
stage functioning as a relief valve when the differential pressure across
the second stage is 12,678 mmHg (215 psi). The relief pressure is vented
into the crew module cabin. The regulated pressure from system No. 1 and
system No. 2 is routed to its respective 14.7 psi CABIN REG (regulator) IN-
LET manual valve, 8 psi EMERG (emergency) REG (regulator), the PAYLOAD O2
manual valve and the XOVER (crossover) O2 regulator and the 14.7 CABIN REG
INLET prevents O2 reverse flow to the 5,175 mmHg (100 psi) regulator.
The two valves in the crossover manifold are controlled by ATM PRESS
CONTROL O2 PRESS SYS 1 and SYS 2 XOVER switches on Panel L2. When a
switch is opened, that oxygen supply system is directed to the AIRLOCK SUP-
PLY OXYGEN 1 and 2 manual valves, AIRLOCK O2 1 and 2 EMU (extravehicular
mobility unit), POS (portable oxygen system), the CDR (commander) and PLT
(pilot) ejection seat oxygen system, and the three face mask outlets. If
both ATM PRESS CONTROL O2 PRESS SYS 1 and SYS 2 XOVER valves are open, oxy-
gen supply systems No. 1 and 2 are interconnected. When the respective ATM
PRESS CONTROL O2 PRESS switch is closed, that oxygen supply system is iso-
lated from the crossover manifold.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 4 of 33
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The emergency O2 tank is made of a filament wound Kevlar fiber with an
Inconel liner. The O2 tank is serviced to a nominal 126,150 mmHg (2, 440
psia) at 26 degrees C (80 degrees F) and stores 29.7 kilograms (67.6 lbs)
of gaseous oxygen. The emergency oxygen supply system is controlled by
the ATM PRESS CONTROL O2 EMER switch on Panel L2. The emergency O2 supply
system is directed to its regulator when the ATM PRESS CONTROL O2 EMER
switch is open and isolated from the regulator when the switch is closed.
An indicator above the switch indicates OP (open) when the valve is open,
CL (close) when the valve is closed, and BARBERPOLE when the motor operat-
ed valve is in transit.
The emergency O2 regulator reduces emergency O2 supply pressure to
15,525 mmHg (300 psi) when the O2 emergency valve is open. The two-stage
regulator has a relief valve. When the differential pressure across the
relief valve is 64,687 mmHg (1,250 psi), the valve will operate. The re-
lief pressure is vented overboard.
The emergency O2 regulated pressure is directed to an O2 EMER manual
valve. When the manual valve is open, the emergency O2 supply is directed
into the O2 crossover manifold. The emergency O2 supply is normally iso-
lated except for ascent and entry.
The check valve between the Freon-21 coolant loop and crossover valve
in the primary and secondary supercritical oxygen supply system prevents
O2 flow from one supply source to the other when the crossover valves are
open.
The primary and secondary gaseous nitrogen supply tanks are identical
to the emergency gaseous oxygen supply tank except that a titanium liner
is used. Each gaseous nitrogen (N2) tank is serviced to a nominal pres-
sure of 153,240 mmHg (2,964 psia) at 26 degrees C (80 degrees F) with a
volume of 134,086 cubic centimeters (8,181 cubic inches). The two N2
tanks in each system are manifolded together. The primary and secondary
nitrogen supply systems are controlled by ATM PRESS CONTROL N2 SYS 1 and 2
SUPPLY switches on Panel L2. When a switch is opened, that nitrogen sup-
ply system is directed to an ATM PRESS CONTROL N2 SYS REG (regulator) IN-
LET valve. When the switch is closed, the nitrogen supply system is iso-
lated from the the N2 SYS REG INLET valve. An indicator above each switch
indicates CL (close) when the valve is closed, OP (open) when the valve is
open, and BARBERPOLE when the motor operated valve is in transit.
Each nitrogen inlet valve is controlled by its respective ATM PRESS
CONTROL N2 SYS REG INLET 1 and 2 switch on Panel L2. When the individual
switch is open, that valve permits that N2 source pressure to that system
N2 regulator, providing the respective N2 supply valve is open. When the
individual switch is closed, the N2 supply pressure is isolated from that
system N2 regulator. An indicator above each switch indicates CL (close)
when the valve is closed, OP (open) when the valve is open, and BARBERPOLE
when the motor operated valve is in transit.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 5 of 33
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The N2 regulators in the primary and secondary supply systems reduce
pressure to 10,350 mmHg (200 psi). Each N2 regulator is a two-stage regu-
lator with the second stage functioning as a relief valve. The second
stage relieves pressure overboard at 14,237 mmHg (245 psi).
The regulated N2 pressure of each N2 system is supplied to the N2
crossover valve, the H2O (water) tank regulator inlet valve, and the O2/N2
controller valve in each N2 system.
The N2 XOVER (crossover) manual valve connects both regulated N2 sys-
tems when the valve is open. When it is closed, the N2 regulated supply
systems are isolated from each other. A check valve between the N2 regula-
tor and N2 crossover valve in each N2 regulated supply line prevents re-
verse flow of N2 when the crossover valve is open.
The H2O TK (tank) N2 REG INLET valve in each N2 regulated supply sys-
tem permits N2 to flow into the H2O regulator when that valve is manually
opened. The closed position isolates the N2 regulated supply from the H2O
regulator.
The H2O tank regulator of each system reduces the 10,350 mmHg (200
psi) supply pressure to 879 mmHg (17 psi). Each H2O tank regulator is a
two-stage regulator. The second stage relieves pressure into the crew mod-
ule cabin at at differential pressure of 1,034 mmHg (20 psi).
Two partial pressure oxygen (PPO2) sensors are located in the crew mod-
ule mid deck cabin air supply duct and another PPO2 sensor is located in
the flight deck return air duct. The PPO2 sensors in the mid deck air sup-
ply duct are sensor A and B and provide inputs to the PPO2 CONTR (control-
ler) SYS 1 controller and switch. Sensor C provides input to a flight
deck controller.
When a PPO2 CNTR <sic> switch is positioned to NORM (normal), the cor-
responding PPO2 controller and PPO2 sensor, in conjunction with the ATM
PRESS CONTROL PPO2 SNSR (sensor)/VLV switch on panel L2 in the NORM posi-
tion, provide electrical power to the corresponding ATM PRESS CONTROL
O2/N2 CNTLR VLV switch on Panel L2 for SYS 1 and SYS 2. When the O2/ N2 CN-
TRL VLV switch is set on AUTO, electrical power automatically controls the
nitrogen valve in the corresponding regulated nitrogen supply. If O2 is
required in the crew module cabin, the nitrogen valve is automatically
closed, the 14.7 psi cabin regulator opens (providing the 14.7 psi CABIN
REG INLET manual valve on that system is open), the 10,350 mmHg (200 psi)
nitrogen supply in the manifold drops below 5175 mmHg (100 psi), and oxy-
gen flows through the check valve and cabin regulator into the crew module
cabin. When sufficient oxygen is present in the cabin as determined by
the PPO2 sensor, the nitrogen valve is opened and 10,350 mmHg (200 psi)
nitrogen enters the manifold. The nitrogen closes the oxygen check valve
and flows through the 14.7 psi cabin regulator into the crew module cab-
in. Oxygen partial pressure is maintained at 178 mmHg (3.45 psi). The
OPEN and CLOSE positions of the N2/O2 CNTLR VLV SYS 1 and SYS 2 switch on
Panel L2 permit the crew to control the nitrogen valve in each system manu-
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 6 of 33
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ally. The REVERSE position of the PPO2 SNSR/VLV switch on Panel L2 allows
Controller B of SYS 1 and Controller A to SYS 2.
If the 14.7 psi CABIN REG INLET manual valves of SYS 1 and SYS 2 are
closed, the crew module cabin pressure will decrease to 8 psi. The PPO2
CONTR SYS 1 and SYS 2 switches on Panel L2 are positioned to EMER (emergen-
cy) for the corresponding nitrogen system which selects the 113.8 mmHg
(2.2 psi) oxygen partial pressure. The corresponding PPO2 sensor and con-
troller, through the corresponding PPO2 CONTR switch and the PPO2 SNSR/VLV
switch on NORM, provide electrical inputs to the corresponding O2/N2 CNTRL
VLV switch. The electrical output from the applicable O2/N2 CNTLR VLV
switch controls the nitrogen valve in that supply system in the same man-
ner as in the 14.7 psi mode except that the crew module cabin partial pres-
sure is maintained at 113.8 mmHg (2.2 psi). In this mode the crew members
would use supplemental oxygen from the portable oxygen system and masks.
The O2 system Nos. 1 and 2 and N2 system Nos. 1 and 2 flows are moni-
tored and sent to the O2/N2 FLOW rotary switch on Panel O1. The rotary
switch permits SYS 1 O2 or N2 or SYS 2 O2 or N2 to be monitored on the O2
or N2 FLOW meter on Panel O1 in PPH (pounds per hour).
PPO2 Sensors A and B monitor the oxygen partial pressure and transmit
the signal to the PPO2 SENSOR select switch on Panel O1. When the PPO2
SENSOR switch is positioned to SENSOR A, oxygen partial pressure from Sen-
sor A is monitored on the PPO2 meter on Panel O1 in psia. If the switch
is set on SENSOR B, oxygen partial pressure from Sensor B is monitored.
The cabin pressure sensor transmits directly to the CABIN PRESS meter
on Panel O1 and is monitored in psia.
A separate PPO2 Sensor C monitors the crew module cabin oxygen partial
pressure and transmits it to a flight deck CRT.
The RED CABIN ATM caution and warning light on Panel F7 would illumi-
nate from any of the following monitored parameters:
Cabin pressure below 14.0 psia or above 15.4 psia
PPO2 below 2.8 psia or above 3.6 psia
O2 flow rate above 5 lbs/hr
N2 flow rate above 5 lbs/hr.
A klaxon will sound in the crew module cabin if the dP/dT (which
stands for change in pressure vs change in time) is greater than 0.05 psi
per minute.
The temperature and pressure of the primary and secondary nitrogen and
emergency oxygen tanks are monitored and transmitted to the SM (systems
management) computer. This information is used to compute O2 and N2 quan-
tities.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 7 of 33
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If the crew module cabin pressure is lower that the pressure outside
the cabin, the negative pressure relief valves will open in a 10 to 36
mmHg (0.2 to 0.7 psi) range differential permitting flow into the crew mod-
ule cabin. The maximum flow rate at 25 mmHg (0.5 psi) differential is 0 to
296 kilograms (654 lbs) per hour.
The crew module cabin vent and vent isolation valves provide the capa-
bility of venting the cabin to ambient following the prelaunch cabin pres-
sure integrity test. These two valves are in series, thus both valves must
be open to vent the cabin. The CABIN VENT VALVE ISOL (isolation) switch on
Panel L2 opens and closes the cabin vent isolation valve. An indicator
above the switch indicates OP (open) when the valve is open, CL (close)
when the valve is closed, and BARBERPOLE when the valve is in transit. The
CABIN VENT VALVE switch on Panel L2 opens and closes the cabin vent valve.
An indicator above the switch indicates in the same manner as in the cabin
vent isolation valve. When both these valves are open, the maximum flow
<at> 10 mmHg (0.2 psi) differential is 408 kilograms (900 lbs) per hour.
The two parallel cabin relief valves provide protection against over-
pressurization of the crew module cabin above 828 mmHg (16.0 psi) differen-
tial. Each cabin relief valve has a backup, motor-operated isolation
valve. CABIN RELIEF switch A controls cabin relief valve A and CABIN RE-
LIEF switch B controls cabin relief valve B. When a switch is positioned
ENABLE, the corresponding cabin relief valve is enabled and when the
switch is positioned to CLOSE, the valve is disabled. An indicator above
each switch shows whether the valve is open or closed. Each cabin relief
valve will flow a maximum of 68 kilograms (150 lbs) per hour.
Approximately one hour and 26 minutes before launch, the crew module
cabin is pressurized by ground support equipment to approximately 864 mmHg
(16.7 psi) for a leak check. The CABIN VENT ISOL and VENT valves are then
opened and the crew module is vented down to 786 mmHg (15.2 psi) or lower.
The CABIN VENT ISOL and VENT valves are then closed.
CABIN AIR. Cabin air cools the cabin avionics electronic units,
the crew, and passengers. Some avionics are cooled by air loops within the
avionics bays. These loops are not pressure isolated from the crew cabin,
although each avionics bay contains a closeout cover to minimize air inter-
change and thermal losses to the cabin environment: therefore, equipment
contained in these air loops meets outgassing and flammability require-
ments to minimize toxicity levels resulting from outgassing materials.
Low-toxicity materials also are used in the crew cabin habitable areas.
The crew module cabin contains five air loops: the cabin, three avion-
ics bays and the inertial measurement unit cooling loop. The crew module
cabin atmosphere is drawn through the cabin through a 300 micron filter by
one of two cabin fans located downstream of the filter.
Each of the cabin fans is controlled individually by the CABIN/FAN
switch<es> on Panel L1. CABIN FAN A switch turns cabin fan A on and off.
CABIN FAN B switch controls cabin fan B. Normally, only one fan is used
at a time.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 8 of 33
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The cabin air is then ducted to the two lithium hydroxide (LiOH) canis-
ters where carbon dioxide (CO2) is removed and activated charcoal removes
odors and trace contaminants. CO2 is maintained at 7.6 mmHg (0.147 psia)
maximum. The two LiOH-activated charcoal canisters are replaced alternate-
ly every 12 hours (for four crew members) via an access door in the mid
deck floor.
The cabin atmosphere is then ducted to the crew module cabin heat ex-
changer where the cabin air is cooled by the water coolant loops. Humidity
condensation is removed from the cabin heat exchanger by a fan separator
which draws air and water from the cabin heat exchanger, separates the air
and water, routes the water into waste water tanks, and ducts the air via
its exhaust into the cabin. The two separator fans are individually con-
trolled by the HUMIDITY SEP (separator) switch on Panel L1. HUMIDITY SEP
switch A controls separator fan A and HUMIDITY SEP switch B operates sepa-
rator fan B. The fan separators separate the air and water by centrifugal
force and remove up to 118 kilograms (4 lbs) <1.8 kilograms ??> of water
per hour. Only one fan separator is used at a time.
A small portion of the revitalized/conditioned air from the cabin heat
exchanger is ducted to the carbon monoxide removal unit (installed after
the second flight of Orbiter 102 and subsequent orbiters), which converts
carbon monoxide into CO2. A bypass duct carries cabin air around the heat
exchanger and mixes with the revitalized/conditioned air to control the
crew module cabin return air at the selected temperature of between 18 to
26 plus or minus 1 degree C (65 to 80 plus or minus 2 degrees F). The CAB-
IN TEMP (temperature) CNTLR (controller) switch on Panel L1 selects the
the cabin temperature controller and the CABIN TEMP SELECTOR rotary switch
on Panel L1 selects the desired cabin temperature which controls the mix-
ing of the bypass air and revitalized/conditioned air before its return to
the crew module cabin ducting.
The three inertial measurement units (IMU's) are cooled by cabin air
drawn through the 300 micron filter and across the three IMU's by one of
three parallel fans. The air is cooled by the water coolant loops which
flow through the IMU heat exchanger and the cooled air is returned to the
cabin. Each of the IMU fans is controlled by individual IMU FAN A, B, and
C switches on Panel L1. When the applicable switch is positioned to ON,
that fan is on and when positioned to OFF, that fan is off. A check valve
installed at the outlet of each fan prevents reverse air flow through the
standby fan chambers.
Each of the three electronic avionics equipment bays has identical air
cooled systems. Air is directed into the avionics bays at floor level and
is drawn through avionics units by connectors at the back of each unit.
The air then returns to the fan package inlet and 300 micron filter up-
stream of two fans. The air is cooled by the heat exchange for each avion-
ics bay. The water coolant loops cool the air and the cooled air is re-
turned to the avionics bays. The two fans in each avionics bay are con-
trolled by an AV (avionics) BAY FAN switch on Panel L1. When the applica-
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 9 of 33
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ble AV BAY FAN switch is positioned to ON, that fan is on and when posi-
tioned to OFF, that fan is off. A check valve in the outlet of each fan
prevents a reverse flow in the standby fan.
The air outlet temperature in each avionics bay and the cabin heat ex-
changer is monitored and sent to the AIR TEMP (temperature) rotary switch
on Panel O1. The rotary switch positioned to AV BAY 1, 2, or 3 position
or CAB (cabin) Hx (heat exchanger) out position permits that temperature
to be displayed on the AIR TEMP meter on Panel O1.
The air outlet temperature in each avionics bay and the cabin heat ex-
changer provides inputs to the YELLOW AV BAY CABIN AIR caution and warning
light on Panel F7. The light would illuminate if any of the avionics bay
outlet temperatures are above 57 degrees C (135 degrees F), if the cabin
heat exchanger outlet temperature is above 18 degrees C (65 degrees F), or
if the cabin fan delta pressure is below 5 mmHg (0.1 psi) or above 15 mmHg
(0.3 psi).
If the payload bay contains the Spacelab pressurized module, a kit is
installed to provide ducting from the crew cabin into the tunnel from the
crew compartment mid deck to the Spacelab.
The fan separators, cabin heat exchanger, avionics heat exchangers and
inertial measurement unit heat exchanger, waste water tanks, LiOH filters,
carbon monoxide unit, and waste and potable water tanks are located be-
neath the mid deck crew compartment floor.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 10 of 33
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WATER COOLANT LOOP SUBSYSTEM
The WCLS provides thermal conditioning of the crew cabin by collecting
heat through air-to-water heat exchangers and transferring the heat from
the water coolant loops to the Freon coolant loops.
There are two complete and separate water (H2O) coolant loops that
flow side by side and have the capability of operating at the same time.
The only difference between H2O Loop No. 1 and 2 is that Loop No. 1 has
two H2O pumps and Loop No. 2 has one pump.
Some of the electronic units in the avionics bays are mounted on cold-
plates with H2O flowing through the coldplates. The heat generated by
that electronic unit is transferred to the coldplate and into the H2O,
which carries the heat away from the electronic unit. Coldplates mounted
on the shelves in the avionics bays are connected in a series - parallel
arrangement with respect to the H2O flow.
The H2O pumps in Loop No. 1 are controlled by the H2O pump Loop 1 A
and B switch on Panel L1 in conjunction with the Loop 1 GPC (general pur-
pose computer) OFF and ON switch on Panel L1. The H2O PUMP LOOP 1 switch
positioned to GPC permits the GPC to energize relays, which cycles H2O
pump A or B for six minutes over a period determined by the GPC and the po-
sition of the H2O PUMP LOOP 1 A or B position. The ON position of the
LOOP No. 1 switch energizes the relays and allows H2O pump A or B to oper-
ate as determined by the position of the H2O PUMP LOOP 1 A or B switch.
The OFF position of the Loop No. 1 switch de-energizes the relays, which
prohibits operation of the Loop No. 1 H2O pump A and B. A ball type check
valve downstream of the H2O pumps prevents reverse flow through the stand-
by pump.
The H2O pump in Loop No. 2 is controlled by the loop 2 GPC ON, OFF
switch on Panel L1. When the switch is in the GPC position, the Loop No.
2 H2O pump is controlled by the GPC as in the case of the H2O pump in Loop
No. 1.
Normally Water Loop No. 2 will be in operation for launch and entry
and during on-orbit operations. Water Loop No. 1 pump B is in operation
under GPC control during the on-orbit operations.
H2O Loops No. 1 and 2 flow side by side through the same areas. Down-
stream of the H2O pump in each loop, the H2O flow splits three ways. One
leg goes through the Avionics Bay No. 1 heat exchanger and coldplates and
provides thermal conditioning of the crew ingress/egress hatch. Another
leg goes through the Avionics Bay No. 2 heat exchanger and coldplates and
provides thermal conditioning of the flight deck cabin windows. The third
leg goes through the flight deck MDM (multiplexer/demultiplexer) cold-
plates with a predetermined amount of H2O bypassing these coldplates and
splits again into two parallel paths for the Avionics Bay No. 3 and 3B
coldplates. All of these paths come together again and flow through the
forward development flight instrumentation (DFI) coldplates to the Freon-
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 11 of 33
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21/H2O heat exchanger where excess heat from the WCL is transferred to the
Freon-21 coolant loops.
The WCL loop flows from the Freon-21/H2O interchanger through the
liquid-cooled garment heat exchanger, H2O water chiller, cabin heat ex-
changer, and IMU heat exchanger to the H2O pump inlet.
The controller for each H2O coolant loop is enabled by its respective
loop BYPASS MODE and MAN switch on Panel L1. The AUTO position of the LOOP
1 BYPASS and LOOP 2 BYPASS switch allows the corresponding controller to
position the bypass valve of that H2O loop automatically. The MAN (manu-
al) position of the LOOP 1 BYPASS and LOOP 2 BYPASS switch disables the au-
tomatic control of the bypass value of that H2O loop and enables the corre-
sponding LOOP 1 BYPASS and LOOP 2 BYPASS MAN INCR DECR switch. The crew
would position the LOOP 1 BYPASS and LOOP 2 BYPASS MAN switch to INCR (in-
crease) or to DECR (decrease) to control that bypass valve in that H2O
coolant loop manually. The bypass valve is adjusted manually prior to
launch to provide 408 to 453 kilograms (900 to 1,000 pounds) per hour
through the interchanger. The control system remains in the manual mode
for the entire flight.
The accumulator in each H2O coolant loop provides a positive pressure
on the H2O pump of the corresponding H2O loop in addition to providing for
thermal expansion capability in that H2O loop. Each accumulator is pres-
surized with gaseous nitrogen at 983 to 1,811 mmHg (19 to 35 psi).
The pressure at the outlet of the H2O pump in each coolant loop is mon-
itored and sent to the H2O PUMP OUT PRESS switch on Panel O1. When the
switch is on LOOP 1 or LOOP 2, that H2O coolant loop pressure can be moni-
tored on the H2O PUMP OUT PRESS meter on Panel O1 in psia.
The YELLOW H2O LOOP caution and warning light on Panel F7 would illumi-
nate if H2O Coolant Loop No. 1 pump outlet pressure is below 2,328 mmHg
(45 psi) or above 4,114 mmHg (79.5 psi) or if H2O Coolant Loop No. 2 pump
outlet pressure is below 2.328 mmHg (45 psi) or above 4,191 mmHg (81 psi).
The pump inlet and outlet pressure of each H2O coolant loop is moni-
tored and transmitted to the SM GPC for CRT capabilities.
In summary, with use of the crew module cabin structural thermal capac-
ity, the crew cabin will not exceed 32 degrees C (90 degrees F) during en-
try or until after flight crew egress, assumed to be 15 minutes after
touchdown.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 12 of 33
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ACTIVE THERMAL CONTROL SUBSYSTEM
The ATCS provides orbiter heat rejection during all mission phases.
The ATCS is composed of two Freon coolant loops (FCL's), coldplate net-
works for avionics cooling, liquid/liquid heat exchangers for orbiter sys-
tems cooling, and three heat sink subsystems (radiators, flash evaporator,
and ammonia boiler).
During ground operations (checkout, prelaunch, and postlanding), orbit-
er heat rejection is provided by the ground support equipment (GSE) heat
exchanger in the Freon coolant loops through ground system cooling.
From lift-off to an altitude greater than 42,672 meters (140,000 feet)
- approximately 125 seconds - thermal lag is utilized. Approximately 125
seconds after lift-off, the flash evaporator subsystem is activated and
provides orbiter heat rejection of the Freon coolant loops via water boil-
ing. Flash evaporator operation continues until the payload bay doors are
opened on orbit.
When the payload bay doors are opened, radiator panels attached to the
forward payload bay doors are deployed. The forward two panels on each
side of the orbiter are deployed away from the payload bay doors and radi-
ate from both sides. The aft radiator panels on the forward portion of
the aft payload bay doors remain affixed to the door and radiate only from
the upper surface. On-orbit heat rejection is provided by the radiator pan-
els; however, during orbital operations where combinations of heat load
and spacecraft attitude exceed the capacity of the radiator panels, the
flash evaporator subsystem is automatically activated to meet total system
heat rejection requirements.
At the conclusion of orbital operations the flash evaporator subsystem
is activated, and the payload bay doors closed with the radiator panels re-
tracted in preparation for entry.
The flash evaporator subsystem operates during entry to an altitude of
36,576 meters (120,000 feet) where the boiling water can no longer provide
adequate Freon coolant temperatures. Through the remainder of the entry
phase and postlanding until ground cooling is connected, heat rejection of
the Freon coolant loops is provided by evaporation of ammonia through the
use of the ammonia boiler. When ground cooling is initiated during post-
landing, the ammonia boilers are shut down and heat rejection of the Freon
coolant loops is provided by the GSE heat exchanger.
There are two complete and identical Freon coolant loops; Loop No. 1
and Loop No. 2. Both Freon coolant loops operate at the same time. There
are two Freon coolant pumps in each loop with only one pump active per
loop. The FCL's flow side by side except for the radiator panels. Freon-21
is utilized in the FCL's.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 13 of 33
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The Freon pumps in each Freon coolant loop are controlled by individu-
al FREON PUMP switches on Panel L1. When the FREON PUMP LOOP 1 or LOOP 2
switch is positioned to A, the Freon pump A in that Freon coolant loop is
in operation. If positioned to B, the Freon pump B in that loop is in op-
eration. The OFF position prohibits either Freon pump operation. A ball
check valve downstream of the pumps in each Freon coolant loop prevents a
reverse flow through the standby pump.
When a Freon coolant pump is operation, Freon is routed in parallel
through the fuel cell heat exchangers and the midbody coldplate network to
cool electronics avionics units. The Freon coolant from the midbody cold-
plate network and fuel cell heat exchanger reunites in a series flow path
before entering the hydraulics heat exchanger, which extracts energy from
the Freon-21 coolant loop to heat the hydraulic systems fluid loops during
on-orbit hydraulic circulation thermal conditioning operations. During
the prelaunch and boost phases of the mission and during the atmospheric
flight portion of entry through touchdown, the hydraulic system heat ex-
changer transfers excess heat from the hydraulic systems to the Freon-21
loops.
The FCL's flow to the radiator system, which consists of three radia-
tor panels (baseline configuration - two deployable and one fixed) at-
tached to the inside of the forward payload bay doors (deployable) and the
forward section of the aft payload bay doors (fixed) and a flow control as-
sembly for each loop. The radiator panels are normally bypassed during as-
cent and descent. On-orbit, the flow control assembly controls the temper-
ature of the loop (mixed radiator outlet) through use of a variable flow
control valve which mixes hot bypassed flow with cold flow from the radia-
tor. The temperature is controlled to either 3 degrees C (38 degrees F)
or 13 degrees C (57 degrees F) setpoint temperature.
The radiator panels on each side of the orbiter are configured to flow
in series while flow within each panel is parallel through a bank of tubes
connected to an inlet and outlet collector manifold.
To increase heat rejection capability for large payloads requiring 29,
000 Btu (British thermal units) per hour of heat rejection, an additional
radiator panel can be kitted into the network by attaching a fixed radia-
tor panel to the inside of the aft section of the aft payload bay doors.
The baseline configuration is designed for payloads rejecting 21,500 Btu
per hour.
A bypass valve in each FCL system permits Freon-21 to bypass the radia-
tors except on-orbit. When Freon-21 temperatures at the radiator outlet
exceed 5 degrees C (41 degrees F), the radiator system heat rejection capa-
bility has been exceeded and the flash evaporators are activated automati-
cally to produce the required Freon-21 temperature.
During boost and entry, each deployable radiator panel is secured to
the payload bay door by six motor-driven latches. Deployment for on-orbit
operations is by a motor-driven, torque-tube-lever arrangement. The aft
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 14 of 33
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four fixed radiator panels are attached to the payload bay doors by a ball
joint arrangement at a maximum of 12 places. The ball joints compensate
for movement of the payload bay door and radiator panel caused by thermal
expansion and contraction of each member. The forward four radiator pan-
els, when deployed, expose both sides of the radiator panels to increase
the heat rejection capability of the Freon-21 loops. The four forward ra-
diator panels are deployed 35.5 degrees from the payload bay doors.
The ATCS pumps, interchanger, fuel cell heat exchanger, payload heat
exchanger, flow proportioning valve modules, and mid body coldplates are
located in the lower forward portion of the mid fuselage. The radiators
are attached to the payload bay doors. The hydraulic systems' heat ex-
changers, ground support equipment heat exchanger, ammonia boiler, flash
evaporator, and aft avionic bay coldplates are located in the orbiter aft
fuselage. The radiator flow control assemblies are located in the lower
aft portion of the mid fuselage.
The radiator panels are constructed of an aluminum honeycomb facesheet
3200 millimeters (126 inches) wide and 8128 millimeters (320 inches) long.
The forward deployable radiator panels are two sided with a core thickness
of 22 millimeters (0.9 inch). They have longitudinal tubes bonded to the
internal side of both facesheets. The forward deployable panels contain 68
tubes each, with a tube spacing of 48 millimeters (1.9 inches). Each tube
has an inside diameter of 3.32 millimeter (0.131 inch). Each side of the
forward deployable radiator panels has a coating bonded by an adhesive to
the facesheet consisting of silver backed Teflon tape for proper emissivi-
ty properties. The aft fixed panels are one sided with a core thickness
of 12.7 millimeters (0.5 inch) with tubes only on the exposed side of the
panel and a coating bonded by an adhesive to the exposed facesheet. The
aft panels contain 26 longitudinal tubes with a tube spacing of 125 milli-
meters (4.96 inches), and each tube has an inside diameter of 4.57 millime-
ters (0.18 inch). The additional thickness of the forward radiator panels
is required to meet deflection requirements when the orbiter is exposed to
ascent acceleration.
The radiator panels on the left-hand side (port) facing forward are
connected in series with Freon-21 coolant loop 1. The panels on the right-
hand side (starboard) facing forward are connected in series with Freon-21
coolant loop 2.
The RAD (radiator) CONTROLLER LOOP 1 and LOOP 2 switch on Panel L1 en-
ables Loops No. 1 and 2 controllers A and B. When the switch for a loop
is positioned to AUTO A, radiator controller A automatically controls the
radiator flow control valve in that loop, which maintains the desired radi-
ator mixed outlet temperature as determined by the RAD CONTROLLER OUT TEMP
switch on Panel L1. When the switch is turned to AUTO B, controller B is
enabled and automatically control the radiator control valve in the corre-
sponding loop as it did in the case of AUTO A.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 15 of 33
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The RAD CONTROLLER OUT (outlet) TEMP switch on Panel L1 enables the se-
lected controller A or B in Loop No. 1 or 2 to control the radiator outlet
temperature of that loop. The radiator outlet temperatures in Loops No. 1
and 2 are automatically controlled at 3 degrees C (38 degrees F) when the
switch is on NORM (normal) and at 13 degrees C (57 degrees F) when it is
on HI. The flash evaporator is activated automatically when the radiator
outlet temperature exceeds 5 degrees C (41 degrees F).
The RAD CONTROLLER MODE 1 and MODE 2 switch on Panel L1 permits auto-
matic control of radiator flow control valve or manual control of the radi-
ator bypass valve. When is the AUTO position for Loop No. 1 or 2, the re-
spective radiator flow control valve automatically controls the radiator
outlet temperature. When in the MAN position, the automatic control of the
radiator flow control valve in the corresponding loop is inhibited and the
bypass valve is controlled by the RAD CONTROLLER MAN (manual) SEL (select)
1 or 2 switch on Panel L1. If the MAN SEL switch is positioned to RAD
FLOW, the bypass valve permits the Freon-21 to flow through the radiators.
If positioned to BYPASS position for that loop, the bypass valve permits
the Freon-21 in that loop to bypass the radiators.
The indicator located above the RAD CONTROLLER MAN SEL 1 and 2 switch
on Panel L1 indicates the position of the bypass valve in that loop. The
indicator indicates BYPASS when the bypass valve is in the bypass posi-
tion, BARBERPOLE when the motor operated valve in that loop is in transit
from the bypass or radiator flow position, and indicates RAD when the by-
pass valve in that loop is in the radiator flow position.
Freon-21 from the radiator flow control valve assembly is routed to
the ground support equipment (GSE) heat exchanger, which is used during
ground operations (checkout, prelaunch, and postlanding) for orbiter heat
rejection of the Freon-21 coolant loops. Freon-21 from the GSE heat ex-
changer is then directed through the ammonia boiler, then the flash evapo-
rator.
The flash evaporator is used to reject orbiter heat loads from the
Freon-21 coolant loops during ascent above 42,672 meters (140,000 feet)
and entry above 36,576 meters (120,000 feet) altitude and to supplement
the radiators in orbit.
There are two flash evaporators (high-load and topping) contained in
one envelope. The evaporators are cylindrical and have a finned inner
core. The hot Freon-21 from the coolant loops flows around the finned core
and water is sprayed onto the core from the nozzles in each evaporator.
The water vaporizes, cooling the Freon-21. In the low-pressure areas
above 36,576 meters (120,000 feet), water vaporizes quickly. The water
changing from liquid to vapor removes approximately 1,000 Btu's per hour
per 1 kilogram (2.2 pounds) of water. The water supply is obtained from
the potable water storage tanks and supply systems A and B.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 16 of 33
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The flash evaporators are controlled by the FLASH EVAP CONTROLLER
switches on Panel L1. The evaporators have three controllers: PRI (prima-
ry) A, PRIB, and SEC (secondary). These controllers are controlled by the
PRIA, PRIB, and SEC switches on Panel L1. Normally, only one of these
switches is used at a time. When one of the PRIA, PRIB, or SEC switches
is positioned to GPC, that controller is turned on by the BFS (backup
flight system) computer as the orbiter ascends above 42,672 meters
(140,000 feet) and is turned off by the BPS <BFS?> computer during entry
at 36,576 meters (120,000). The ON position of the PRIA, PRIB, or SEC
switch provides power to the flash evaporator controller directly. OFF re-
moves power form the flash evaporator controller. The PRIA controller uti-
lizes water system A; the PRIB controller utilizes water system B. The
SEC controller uses water system A if the SEC switch on Panel L1 is in
SPLY A or B if the SEC switch on Panel L1 is in SPLY B and the HI-LOAD
EVAP switch is in the ENABLE position.
The PRIA and B controllers control evaporator outlet Freon-21 loop tem-
peratures at 3 degrees C (39 degrees F) and the SEC controller controls
evaporator outlet Freon-21 loop temperatures at 16 degrees C (62 degrees
F).
The applicable flash evaporator controller pulses water into the evapo-
rators, cooling the Freon-21. The steam generated in the topping evapora-
tor is ejected through two sonic nozzles at opposing sides on each side of
the aft end of the orbiter, reducing payload water vapor pollutants on or-
bit and minimizing vent thrust effects on the orbiter guidance navigation
and control system. The hi-load evaporator is used in conjunction with the
topping evaporator during ascent and entry when higher Freon-21 coolant
loop temperatures impose a greater heat load which requires a higher heat
rejection. The HI-LOAD EVAP ENABLE switch on Panel L1 must be in the EN-
ABLE position for hi-load evaporator operation. After leaving the hi-load
evaporator, the Freon-21 would also flow through the topping evaporator
for additional cooling. The steam generated by the hi-load evaporator is
ejected through a single sonic nozzle on the left hand (port) side aft end
of the orbiter facing forward. The hi-load evaporator would not normally
be used on orbit because it has a propulsive vent and might pollute the
payload.
The topping evaporator can be used to dump excess potable water from
the storage tanks. In this mode, the radiator flow control valve assembly
has an alternate control temperature of 13.8 degrees C (57 degrees F),
which is used during forced water dumping.
Heaters are employed on the topping and hi-load steam ducts of the
flash evaporator to prevent freezing. The HI-LOAD DUCT HTR (heater) switch
on Panel L1 positioned to A provides electrical power to the thermostati-
cally controlled A heaters on the hi-load evaporator steam duct and steam
duct exhaust. The B position provides electrical power to the thermostati-
cally controlled B heaters on the hi-load evaporator steam duct and steam
duct exhaust. The A/B position provides electrical power to both the A and
B heaters. The C position provides electrical power to the thermostatical-
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 17 of 33
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ly controlled C heaters on the hi-load evaporator steam duct and steam
duct exhaust. The OFF position removes electrical power from the heaters.
The TOPPING EVAPORATOR HEATER L (left) and R (right) NOZZLE switches
on Panel L1 provide electrical power to the topping evaporator left and
right nozzles. The L and R AUTO A position provides electrical power to
the left and right A nozzle heaters to maintain nozzle temperatures be-
tween 4 degrees and 21 degrees C (40 degrees and 70 degrees F). The L and
R AUTO B position provides electrical power to the left and right B nozzle
heaters.
The ammonia boilers are used below 36,576 meters (120,000 ft.) during
entry. There are two individual storage and control systems that feed a
boiler containing common ammonia passages and individual Freon-21 coolant
loop passages. This provides a safe return from orbit for any combination
of failures in both the Freon-21 coolant loops and ammonia boilers. The
ammonia boilers are enabled by the NH3 CONTROLLER A and B switches on Pan-
el L1. The NH3 CONTROLLER A and B switches are positioned to PRI (prima-
ry)/GPC before entry. As the orbiter descends through 36,576 meters
(120,000 ft.), the BFS commands controller A and B on. The ammonia (NH3)
boiler is a shell-and-tube type with a single pass on the ammonia side and
two passes for each Freon-21 coolant loop. The NH3 flows in the ammonia
tubes and the Freon-21 coolant loops flow over the tubes, cooling the
Freon-21. Freon temperature is maintained at 1.1 degrees C (34 degrees F)
by regulating the flow of NH3 through the boiler. Freon-21 temperature is
monitored by three temperature sensors. One sensor is associated with the
primary NH3 flow control valve of that loop and another with the secondary
NH3 flow control valve. The third sensor automatically switches control
from the primary to the secondary system in the event of low Freon-21 cool-
ant outlet temperature. The NH3 boiler exhaust is vented overboard in the
aft section of the orbiter adjacent to the bottom right side of the verti-
cal tail. The boiler continues to operate and provide heat rejection un-
til a ground cooling cart is connected to the GSE heat exchanger after
touchdown.
The NH3 CONTROLLER A and B switch positioned to SEC (secondary) ON pro-
vides electrical power directly to the NH3 controllers and boiler, which
operates the NH3 boiler. The OFF position removes electrical power from
the NH3 controllers and boiler. The two complete ammonia boiler systems
each have an ammonia storage tank. The capacity of each tank is 29 kilo-
grams (64.7 lbs.). There is about 20 kilograms (46 lbs.) usable for each
system. Each ammonia tank is pressurized with helium at an operating pres-
sure between 4,295 and 28,462 mmHg (83 to 550 psi). There are three
valves in the plumbing leading to each ammonia boiler. The isolation valve
is opened by the primary or secondary controller. The next two control
valves in line are modulating valves whose position is dependent on the
amount of current to the control motor. The full closed position of these
two valves inhibits about 75 percent of the flow. The fail mode of the con-
trol valves is open. If the fault circuitry detects the Freon-21 outlet
temperature below minus 0.4 degrees C (31.25 degrees F) for greater than
10 seconds, an automatic switchover occurs in the controller for that NH3
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 18 of 33
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system and the secondary controller takes over. A relief valve provides
over pressurization protection for each ammonia tank.
Freon Coolant Loops No. 1 and 2 are routed from the flash evaporator
in series, then into parallel paths. A portion of the Freon-21 loop is di-
rected to the aft avionics bays in the aft fuselage of the orbiter, where
some of the electronic avionics units in Avionics Bays 6, 5 and 4 are
mounted on coldplates which transfer the heat generated from the electron-
ic avionics units to the Freon-21, which carries the generated heat away.
The Freon-21 coolant loops also flow through the coldplates of Rate Gyro
Assemblies 1, 2, 3 and 4.
The remaining parallel path downstream of the flash evaporator heats
oxygen by means of a heat exchanger to 4.4 degrees C (40 degrees F) prior
to entering the cabin. The source of the oxygen is the cryogenic storage
and distribution system. This path branches in parallel at the flow pro-
portioning valve in each Freon-21 loop.
The FLOW PROP (proportioning) VLV (valve) switch on Panel L1 for each
coolant loop controls the flow of Freon-21 to the payload heat exchanger
or the water/Freon-21 interchanger. The INTCHGR (interchanger) position
of the LOOP 1 and LOOP 2 switches controls the respective flow proportion-
ing valve to allow maximum Freon-21 flow through the water/Freon-21 inter-
changer. The PAYLOAD HX (heat exchanger) position of the LOOP 1 and LOOP
2 switch controls the respective flow proportioning valve to allow maximum
Freon-21 flow through the payload heat exchanger. The indicator above the
respective LOOP 1 and LOOP 2 switch on panel O1 indicates ICH when <in>
the water/Freon-21 interchanger position, BARBERPOLE when that valve is in
transit from ICH or PL, and indicates PL (payload) when that valve is in
the payload heat exchanger position.
The parallel paths from the water/Freon-21 interchanger and payload
heat exchanger are reunited with the parallel paths from the aft avionics
bay and rate gyro assemblies. The coolant loop then returns to its Freon-
21 coolant pump.
The accumulator in each Freon-21 coolant loop is a metal, bellows-type
pressurized with gaseous nitrogen. The accumulator provides for the ther-
mal expansion and keeps a positive suction on the coolant pumps.
The Freon-21 coolant loop temperature and flow rate are monitored on
Panel O1. When the FREON FLOW EVAP OUT TEMP switch is positioned to LOOP
1 or LOOP 2, the respective Freon-21 coolant loop evaporator outlet temper-
ature is monitored on the FREON EVAP OUT TEMP in degrees Fahrenheit and
the Freon flow is monitored on the FREON FLOW in PPH (pounds per hour).
This information is also transmitted to the RED FREON LOOP caution and
warning light on Panel F7. The RED FREON LOOP light would illuminate if
the Freon-21 Coolant Loop No. 1 or 2 evaporator outlet temperature fell be-
low 0 degrees C (32 degrees F) or rose above 15.6 degrees C (60 degrees F)
or if the Freon-21 flow rate is below 544 kilograms (1,200) lbs.) per
hour.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 19 of 33
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During the development flights of Orbiter 102, a separate development
flight instrumentation (DFI) Freon-21 coolant loop system is installed in
the payload bay for cooling the electronic units installed on the DFI pal-
let in the payload bay. The DFI has its own Freon-21 pumps, accumulator
and plumbing. The DFI Freon-21 coolant loop is cooled by the payload bay
heat exchanger. The DFI FREON PUMPS SELECT switch is located on Panel R11.
Position 1 controls pump No. 1 and position 2 controls pump No. 2.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 20 of 33
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FOOD, WATER, AND WASTE MANAGEMENT
The food, water, and waste management (FWW) subsystem provides the ba-
sic life support functions for the flight crew.
Each potable water tank has a usable capacity of 74 kilograms (165
pounds), is 901 millimeters (35.5 inches) in length and 393 millimeters
(15.5 inches) in diameter, and weighs 17.9 kilograms (39.5 pounds) dry.
Potable water is generated by the three fuel cells at a maximum of
11.34 kilograms (25 lbs.) per hour. The hydrogen enriched water from the
fuel cells passes through a hydrogen (H2) separator where 95 percent of
the excess hydrogen is removed. The H2 separator consists of a matrix of
silver palladium tubes which have an affinity for H2. The H2 is dumped
overboard through a vacuum vent.
The water from the H2 separator is directed to the water storage sys-
tem, which can consist of a total of six tanks for the development flight
test missions. The tanks are identified as A, B, C, D, E and F. Tanks E
and F are located on the mid deck of the crew module cabin for the develop-
ment flights of Orbiter 102. Each tank has a solenoid inlet and outlet
valve except Tanks E and F, which have manual valves. Water for Tank A
passes through a microbial check valve. The microbial check valve adds ap-
proximately 3.5 parts per million iodine to the water. The water from the
microbial check valve is directed to Tank A and the galley. The crew can
select cooled or ambient water. Cooling is accomplished by passing
through the water chiller, where heat is rejected to the water coolant
loop.
When the Tank A inlet valve is closed or Tank A is full, the water is
directed through a 77 mmHg (1.5 psi) relief valve which routes the water
to Tank B.
When the Tank B inlet valve is closed or Tank B is full, the water is
directed through another 77 mmHg (1.5 psi) relief valve to Tanks C, D, E
and F. The inlet and outlet valves for each tank can be opened or closed
selectively to use water; however, the Tank A outlet valve fill always re-
mains closed since the water has been treated by passage through the micro-
bial filter for crew consumption.
The controls for the water supply system are located on Panels R12 and
ML31C. Tanks A, B, and C are controlled from Panel R12, Tank D from Panel
ML31C, and Tanks E and F from manual valves on the tanks.
Tanks A, B, and C have their own SUPPLY H2O INLET and OUTLET switch on
Panel R12. When the SUPPLY H2O INLET TK A, B, or C switch is positioned
to OPEN, the inlet valve for that tank allow water into the tank. If posi-
tioned to CLOSE, the inlet valve isolates the water inlet from that tank.
An indicator located above the respective switch on Panel R12 indicates OP
(open) when the corresponding valve is open, BARBERPOLE when that valve is
in transit, and CL (close) when that valve is closed. Tank D has its own
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 21 of 33
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SUPPLY H2O TK INLET switch and indicator on Panel ML31C and operates in
the same manner as the ones on Panel R12.
A SUPPLY H2O GALLEY SPLY (supply) VLV (valve) switch on Panel R12 per-
mits or isolates water from Tank A to the galley. The switch has OPEN and
CLOSE positions and an indicator above the switch shows whether the valve
is open or closed, or BARBERPOLE when that valve is in transit.
When the valve is open, water is supplied to an Apollo water dispenser
and water gun at ambient and chilled temperatures for drinking and food re-
constitution. The ambient water temperature range is 18 to 35 degrees C
(65 to 95 degrees F) and the chilled water temperature range is 6 to 13 de-
grees C (43 to 55 degrees F) for the development flight tests. In the op-
erational flights, the water supply to the galley is directed to a hot wa-
ter heater, which provides hot water at a temperature range between 68 and
73 degrees C (155 to 165 degrees F). Chilled water is supplied at the gal-
ley at a temperature range of 7 and 12 degrees C (45 to 53 degrees F).
Tank A is used for crew consumption. To prevent contamination the Tank
A OUTLET valve will remain closed. Tank B is used for flash evaporator
cooling on-orbit. Tanks A and B may also be dumped overboard as necessary
to provide space for water storage. Tanks C, D, E, and F are saved full of
water for contingency purposes.
Each of the water tanks is pressurized from the nitrogen pressure sup-
ply system at a pressure of 905 mmHg (17.5 psi) to force the water from
the water storage tanks for flash evaporator use. The H2O ALTERNATE PRESS
switch on Panel L1 provides the capability of referencing the water tank
pressurization system to ambient cabin pressure if the N2 system fails.
If the switch is positioned to OPEN, cabin atmosphere pressure is supplied
to the water tanks for pressurization. The CLOSE position isolates the
cabin atmosphere pressure from the water tank pressurization supply sys-
tem.
From the water supply tanks, two evaporator feed lines referred to as
SYSTEM A and SYSTEM B are routed to the flash evaporators in the aft fuse-
lage. A crossover valve between the two supply systems is controlled by a
SUPPLY H2O CROSSOVER VLV switch on Panel R12. If the switch is positioned
to OPEN, the crossover valve allows all six water tanks for the flash evap-
orator or overboard dumping. When the switch is positioned to CLOSE, the
crossover valve is closed, and Tanks C, D, E, and F cannot be used for the
flash evaporator A water supply. But by opening the B supply isolation
valve, these tanks can flow to B water supply and, thus, the flash evapora-
tor. An indicator above the switch indicates OP (open) when the valve is
open, CL (close) when the valve is closed, and BARBERPOLE when the valve
is in transit.
The water supply system B to the flash evaporator has an additional
supply isolation valve. This valve is controlled by the SUPPLY H2O B SPLY
(supply) ISOL VLV switch on Panel R12. An indicator above the switch on
Panel R12 indicates the same as in the previous paragraph.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 22 of 33
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Water from Tank A, when full, and Tank B can also be dumped overboard.
The overboard dump consists of a dump isolation valve in the crew module
cabin and a dump valve in the mid fuselage. Both valves are closed unless
performing a dump. The SUPPLY H2O DUMP ISOL VALVE switch on Panel R12
opens and closes the dump isolation valve in the crew module cabin. The
SUPPLY H2O DUMP VLV switch on Panel R12 controls the dump valve in the mid
fuselage. Indicators above the switches indicate OP (open) when the
valves are open, CL (close) when the valves are closed, and BARBERPOLE
when the valves are in transit.
The water dump nozzle has a heater to prevent freezing. The heater is
controlled by the DUMP VALVE ENABLE/NOZZLE HEATER switch on Panel R12. The
nozzle heater is powered when the switch is positioned to ON.
There are thermostatically controlled line heaters upstream of the wa-
ter dump nozzle on the line. The heaters are powered by circuit breakers
H2O LINE HTR A and B on Panel L2. The switch enables the thermostatically
controlled heaters on H2O system A and B. Heater circuit one or two on
PR1 then A or B may be selected. The OFF position of either switch re-
moves electrical power from the heaters.
The orbiter is equipped with food and facilities for food stowage and
preparation and dining to provide each crew member with three meals plus
snacks per normal day in orbit; two meals on launch day; one meal on reen-
try day; and an additional 96 hours of contingency food. The food supply
and food preparation facilities are furnished by the government and are de-
signed to accommodate variations in the number of crew and duration of
flight, ranging from a crew of two for one day to a crew of seven for 30
days.
In the development test flights, the food preparation system is limit-
ed. It consists of the water dispenser, food warmer, food trays, food
(meal menu and pantry), and food system accessories.
The food warmer is a small, portable, thermostatically controlled unit
that can warm meals for two crew members simultaneously. The food trays
serve as a dining surface with restraints for food items and provide each
crew member with associated dining accessories. The food consists of indi-
vidually packaged items of dehydrated, thermo-stabilized, irradiated, in-
termediate moisture, natural form and beverage form. Meal accessories in-
clude salt, pepper, sauces, etc., as well as candy gum, vitamin tablets,
wipes, utensils, thermal pads, drinking containers, and germicidal tab-
lets.
For the operational flights, the food preparation system consists of
the galley, food trays, work/dining table, food, and food system accesso-
ries.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 23 of 33
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The galley is a multipurpose facility that provides food preparation
facilities, stowage of meal accessories, food trays and oven inserts, and
food, and volume for seven crew member days of food related trash. The
food consists of individually packaged items of rehydratable,
thermo-stabilized, and ready-to-eat food and beverages.
The food warmer will heat a meal for two crew members in approximately
two hours in the development flight tests.
The oven will heat a meal for up to seven in approximately 90 minutes
and has a heating range of 62 to 85 degrees C (145 to 185 degrees F) in
the operational flights.
The waste management system collects, processes, and stores solid and
liquid wastes. Liquid waste consists of urine, perspiration, lung vapor,
and liquid waste from the galley and extravehicular mobility unit (EMU).
Solid waste consists of feces, emesis, tissues, etc. The waste collection
system collects and processes these wastes in zero gravity.
The waste collection system is located in the mid deck of the orbiter
crew compartment in a 736 millimeter (29 inch) wide area immediately aft
of the crew side hatch. The unit is 685 x 685 x 736 millimeters (27 x 27
x 29 inches) and has two major independent and interconnected assemblies:
one handles fluids and the other (commode) the solid waste.
The fluid processing assembly collects liquid waste from the urinal,
personal hygiene station or EMU (extravehicular mobility unit). The urinal
assembly is a flexible hose with a cup that can be used in a standing posi-
tion or be attached to the commode by a pivoting mounting bracket for use
in a seated position. The urinal is a contoured cup that can accommodate
both males and females.
The urinal can be used sitting or standing by either male or female
crew members. The user positions the waste collection system (WCS) con-
trol panel MODE switch to the WCS/EMU which opens the fan separator valve
1 or 2 and turns fan separator 1 or 2 on, dependent upon the WASTE COLLEC-
TION SYSTEM FAN SEP switch in position 1 or 2, opens the fan separator con-
trol valve, and opens the urine collection valve. The COMMODE CONTROL han-
dle is positioned to OFF, which allows the commode outlet control valve
port to vent to the WCS VACUUM VALVE in the OPEN position to expose the
wastes in the commode to vacuum for drying, and the ballast air control
valve is open. The air flow in the urinal and the ballast air flow enter
the system via the debris screen inlet, orifice and ballast air control
valve. The ballast air mixes with the urine transport air flow in the fan/
separator. The air/fluid mixture in the fan separator is conveyed axially
in the rotating chamber and centrifugal force draws the fluid along the
outer walls of the chamber. A stationary pitot tube picks up the fluid and
pumps it to the waste water tank. The air is drawn axially out of the ro-
tating chamber by blower action and passes through a filter which removes
all bacteria and odors before returning the air into the cabin. An EMU wa-
ter dump is accomplished in the same manner.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 24 of 33
---------------------------------------------------------------------------
Wash water removal from the personal hygiene station (PHS) is accom-
plished in the same manner, except that the WASTE COLLECTION SYSTEM MODE
switch is positioned to PHS. This portion of the system is inactive for
the development flight tests.
The check valve at the waste water outlet from the fan separators pro-
vide back pressure for proper separator operation and prevent backflow
through the inactive separator.
The urine and feces collection mode is accomplished by using the foot
restraints, sitting on the commode, locking the restraint belt, and posi-
tioning the urinal.
The WCS VACUUM VALVE is positioned to open, opening the vacuum vent
valve. This operation is performed prior to the first usage and reversed
subsequent to the last usage. The WCS/EMU MODE switch is positioned to
WCS/EMU as in the urine collection mode. The COMMODE CONTROL handle is
pulled up, which closes the commode outlet control valve port to the vacu-
um vent and opens the commode control valve and commode pressurization
valve to pressurize the commode from the cabin, and the ballast air con-
trol valve is open. The WASTE COLLECTION SYSTEM SLINGER switch is posi-
tioned to the FECES position, which operates the slinger in the commode at
high speed. After 10 seconds the COMMODE CONTROL handle is positioned FOR-
WARD to open the gate valve, opening the collector for use. The equipment
is used as a normal toilet, including toilet wipes. The urine is collect-
ed as in the urine collection mode and the feces and tissue are conveyed
into the commode.
The solids/air mixture is accelerated into the rotating slinger, where
the tines shred the feces and accelerate the wastes to the commode inner
wall, where it adheres in a thin layer around the periphery. The tissue is
not shredded but slides up and over the rotating tines and into the stor-
age volume. Air is drawn through the collector by the fan/separator and
returned to the cabin through the odor/bacteria filter.
The deactivation of urine and feces collection would be done in re-
verse procedure. Emesis collection is accomplished in the same manner as
feces collection, except that the EMESIS/FECES switch is positioned to EME-
SIS. The EMESIS position slows the rotation of the slinger allowing the
slinger tines to remain folded against the plate, which clears the passage
from the commode inlet to the exterior of the commode storage compartment.
After use the emesis bag is sealed and lowered into the open commode inlet
and the bag moves into the storage area.
When the waste collection system is not in use, the commode is exposed
to space vacuum. The commode control handle on OFF opens the commode thor-
ough the commode outlet control valve port to the WCS VACUUM VALVE, which
is positioned to OPEN to dry and disinfect the wastes. The WASTE COLLEC-
TION SYSTEM MODE switch positioned to OFF closes the urine collection
valve and fan separator outlet control valve.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 25 of 33
---------------------------------------------------------------------------
The commode has a storage capacity equivalent to 210 crew member-days
of vacuum dried feces and toilet tissue. Each crew member-day usage re-
sults in 0.12 kilogram (0.27 pound) of fecal and paper waste, including
0.09 kilogram (0.2 pound) of moisture. The commode can accommodate up to
four usages per hour.
Heaters are installed on the vacuum vent line and are thermostatically
controlled. Heaters are also installed on the vacuum vent nozzle and are
enabled by the WASTE H2O VAC VENT NOZZLE HEATER switch on panel ML31C when
positioned to ON. The WCS waste gases are vented overboard through the
vacuum vent line and nozzle.
Personal hygiene accommodations for the crew include a personal hy-
giene station, personal hygiene kits, pressure packed personal hygiene
agents, towel dispenser, and tissue dispenser.
In the development flight tests, the personal hygiene station is locat-
ed in the mid deck of the crew cabin and provides ambient temperature wa-
ter with no drain. The operational flight personal hygiene station is on
the aft side of the galley in the mid deck of the crew cabin and provides
ambient and hot water plus a drain to the urinal assembly.
Personal hygiene kits provide for brushing teeth, hair care, shaving,
nail care, etc. Pressure packaged personal hygiene agents are for clean-
ing hands and for cleaning hands, face, and body. A seven day supply of
towels is provided for each crew member; additional towel dispensers are
provided for each crew member for each additional seven days. Tissues are
provided to support each crew member for seven days and dispensers are add-
ed for each seven days added to a mission.
In the operational flights, two privacy curtains are attached to the
waste collection compartment door. One is attached to the top of the door
and interfaces with the edge of the inter-deck access. The other is at-
tached to the door and interfaces with the galley. The deployed curtain
isolates the waste collections compartment and galley personal hygiene sta-
tion from the rest of the orbiter mid deck.
The waste water tank receives waste water from the ARS crew compart-
ment humidity separator and the waste collection system urine separator.
The waste water tank usable capacity is 74 kilograms (165 pounds). It
is 901 millimeters (35.5 inches) in length and 381 millimeters (15 inches)
is diameter and weighs 17.9 kilograms (39.5 pounds) dry.
The waste water tank is pressurized with the same gaseous nitrogen
source supply as the potable water tanks. The waste water tank has an in-
let and outlet valve. The outlet valve is opened only for ground servicing
and controlled by the WASTE H2O TK/DRAIN VALVE switch on panel ML31C. The
valve is opened when the switch is positioned to OPEN and closed when <po-
sitioned to CLOSE. An indicator above the switch indicates> OP (open)
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 26 of 33
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when the valve is open, CL (close) when the valve is closed, and BARBER-
POLE when the valve is in transit.
The inlet valve permits waste water from the cabin heat exchanger hu-
midity separator and waste fan/separators to enter the waste tank. The in-
let valve is controlled by the WASTE H2O TANK 1 VLVE switch on Panel
ML31C. The switch opens and closes the valve. An indicator above the
switch indicates the position of the valve in the same manner as the previ-
ous paragraph.
In order for waste water to be dumped overboard, the dump isolation
valve must be opened. The dump isolation valve is controlled by the WASTE
H2O DUMP ISOL VLV switch on Panel ML31C. An indicator above the switch in-
dicates the position of the valve in the same manner as the previous para-
graph.
A redundant waste water dump valve must also be opened to dump waste
water overboard. This valve is controlled by the WASTE H2O DUMP VALVE
switch on panel ML31C. The WASTE H2O DUMP ENABLE/NOZ HTR switch must by
on before the dump valve can be activated. An indicator above the switch
indicates the position of the valve in the same manner as the previous
paragraph.
A heater installed on the waste water dump nozzle is turned on and off
by the WASTE H2O DUMP VLV ENABLE/NOZ HTR switch on Panel ML31C. Heaters
are installed on the waste water dump line and are thermostatically con-
trolled.
Waste water tanks may be added in parallel if a mission requires addi-
tional stowage of waste water. The potable water tanks have a similar over-
board dump capability.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 27 of 33
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AIRLOCK SUPPORT SUBSYSTEM
The airlock eliminates the necessity for crew compartment depressuriza-
tion for extravehicular activity (EVA) and Spacelab operations that re-
quire crew/equipment transfer from the crew cabin to the payload bay or to
the Spacelab.
The airlock is normally located in the mid deck of the crew cabin. It
will contain two pressure sealing hatches. The airlock may also be located
in one of two additional locations. The airlock may be moved from inside
the mid deck of the crew cabin and positioned outside the aft bulkhead of
the crew cabin in the payload bay area to provide additional volume in the
mid deck. When the airlock is in the payload bay, insulation is installed
on the exterior of the airlock for protection against temperature ex-
tremes.
If Spacelab is in the payload bay, a transfer tunnel and adapter en-
ables the crew members and equipment to be transferred between the Spa-
celab and the crew cabin. The tunnel mates with a tunnel adapter at the
forward end of the payload bay. For EVA, the airlock is positioned on top
of the tunnel adapter and stabilized through a structural connection to
the crew compartment aft bulkhead. The tunnel adapter will have two access
hatches: one on top of the adapter for access to the airlock and the other
on the aft end for access to the Spacelab.
For missions requiring direct docking of two vehicles, a docking mod-
ule can be substituted for the airlock and installed on the tunnel adapt-
er. The docking nodule is extendable and provides an airlock function for
EVA for two crew members when extended or for one crew member when retract-
ed.
The airlock has an inside diameter of 1600 millimeters (63 inches), is
2108 millimeters (83 inches) long, and has two 1016 millimeters (40 inch)
diameter, D-shaped openings, 914 millimeters (36 inches) across, plus two
pressure sealing hatches and a complement of airlock support systems.
The airlock volume is 4.24 cubic meters (150 cubic feet). Airlock re-
pressurization is controllable from inside the crew cabin mid deck and
from inside the airlock. It is performed by equalizing the airlock and cab-
in pressure with hatch-mounted equalization valves. Depressurization is
controlled from inside the airlock. The airlock is depressurized by vent-
ing the airlock overboard.
The airlock provides EVA capabilities up to seven hours and suited
intra-vehicular activity (IVA) activities. The airlock support provides
airlock pressurization and depressurization, EVA equipment recharge,
liquid- cooled garment water cooling, prebreathing support, EVA equipment
checkout, donning and communications.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 28 of 33
---------------------------------------------------------------------------
The EVA equipment recharge station provides oxygen, water, waste water
processing, and battery recharge of the extravehicular mobility units
(EMU's). Oxygen is supplied to the EVA equipment recharge panel from the
ARS oxygen supply. Potable water is supplied to the recharge panel from
the potable water system. Waste water processing from the EMU is expelled
to the waste water system.
A service and cooling umbilical (SCU) is used to transport all sup-
plies (oxygen, H2O, electrical, communications, etc.) from the airlock con-
trol panels to the EMU before and after EVA and during EMU recharge.
Cooling for the crew is provided by the liquid-cooled garment circulation
system via the SCU and liquid-cooled garment heat exchanger, which trans-
fers collected heat to the Freon-21 coolant loops.
The EMU's are warn over a liquid-cooled garment to a "long john" under-
wear into which have been woven many feet of flexible tubing that circu-
lates the cooling water.
An EMU power supply/battery charger supplies electrical power to the
EMU for pre- and post-EVA operations and recharge of the EMU batteries be-
tween EVA's.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 29 of 33
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PORTABLE OXYGEN SUBSYSTEM
A portable oxygen system is provided for each crew member. The system
is used in the event of crew cabin atmosphere contamination and for life
support during EVA rescue operations, emergency oxygen after landing if
the atmosphere around the orbiter is contaminated, and prebreathing for
EVA's for denitrogenizing the crew member's circulatory system.
The portable oxygen system consists of a full face mask with visor, re-
breather loop, heat exchanger, oxygen bottle, CO2 absorber, and condensate
collector. It operates independently or connected to the ARS oxygen sys-
tem. The portable oxygen system rebreather concept limits spillage of oxy-
gen in the crew cabin. A communications cable provides the mask with com-
munications capabilities. A recharge kit consists of the CO2 absorber car-
tridge and condensate collector.
The portable oxygen system provides for three hours of operation using
ARS oxygen before recharge kit replacement. The portable oxygen provides
a walk-around capability for normal and emergency operation. Its internal
oxygen supply will provide up to one hour of independent rebreather opera-
tion when in EVA personal rescue system. After the internal oxygen supply
is depleted, the portable oxygen system can be recharged to provide a 10-
minute independent walk-around capability in the rebreather mode.
Oxygen is supplied from the ARS to the portable oxygen system through
quick-disconnect flexible hoses.
The development test flights have nine available locations for the por-
table oxygen system: three at the aft center console, four on the mid deck
and two in the airlock. The operational flights will have 10 portable oxy-
gen system locations available: two in the airlock, four on the mid deck
ceiling, and four on the aft center console.
Before the EVA's, the crew member must be denitrogenized to prevent
the bends when EVA's are begun in the 212 mmHg (4.1 psi) EMU suit.
If an extravehicular activity (EVA) is required to close the payload
bay doors, crew cabin pressure will be reduced from 750 mmHg plus or minus
10 mmHg (14.5 plus or minus 0.2 psia) to 465 mmHg plus or minus 23 mmHg (9
plus or minus 0.45 psia) is STS-1 through STS-4 with an 80 percent nitro-
gen and 20 percent oxygen (mixed gas) composition by the spacecraft's envi-
ronmental control life support system (ECLSS) atmospheric revitalization
pressure control subsystem (ARPCS).
The reduction of the cabin pressure eliminates the 3.5 to 4 hours pre-
breathing of pure oxygen by the two-man flight crew to force nitrogen from
their blood in preparation for the 100 percent 258 mmHg (5 psia) of the
EVA space suits in addition to providing a prebreathing atmosphere for
both crew members simultaneously, thereby facilitating an emergency EVA by
the second crewman. The reduction of cabin pressure provides positive den-
itrogenization and avoids the encumbrance of the portable oxygen system
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 30 of 33
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and the servicing and cooling umbilical for prebreathing, permitting the
flight crew to accomplish other pre-EVA tasks more effectively.
If an EVA is required, depressurization of the cabin from 750 mmHg
plus or minus 10 mmHg (14.5 plus or minus 0.2 psia) to 465 mmHg plus or mi-
nus 23 mmHg (9 plus or minus 0.45 psia) will be implemented at an interval
of 12 to 67 hours prior to the EVA.
During depressurization, the total cabin pressure and oxygen partial
pressure are controlled manually by the flight crew. The cabin pressure
reduction results in an oxygen concentration of up to 30 percent. Appro-
priate analyses and tests are being conducted on equipment and materials
to verify their performances in the reduced pressure environment.
During the period of cabin pressure reduction, a procedural powerdown
is necessary to maintain operational cabin and avionics temperature levels
because of the reduced air cooling capability.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 31 of 33
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EJECTION ESCAPE SUIT
The ejection escape suit (EES) provides the crew member with a safe en-
vironment in the event of crew ejection from the orbiter during high speed
- maximum of Mach 2.7 - and high altitude - maximum of 24,384 meters (80,
000 feet) - in the development flight tests.
The pressure portion of the EES is a five layer integral unit covering
the torso to the neck, the arms above the wrists, and legs including the
feet. The EES includes a helmet, gloves, boots, and outer garment.
The EES is donned in preflight phase, removed in orbit, and donned
again before descent and worn until after landing.
Regulated oxygen is supplied to the EES helmet by means of a regula-
tor/valve/manifold assembly. The oxygen supply is derived from the power
reactant storage and distribution cryogenic system, from the ECLSS ARS
emergency breathing oxygen supply, or from the crew member ejection seat
oxygen supply during crew ejection. A portable ventilator system is used
with the suit before crew members enter the orbiter.
The suit weighs approximately 10 kilograms (23.5 pounds).
The escape suit ventilation system (ESVS) provides ventilation for the
EES. Air is drawn from a manifold supplying conditioned cabin air from
the ECLSS air circulation duct located in the crew cabin mid deck sleep ar-
ea. The air is drawn by two compressors and discharged through a check
valve to a common manifold for the commander and pilot. The check valve
prevents a reverse flow of air in the event of a compressor failure. The
compressors are located on the crew cabin flight deck immediately behind
the ejection seat. The discharge port at the common manifold is connected
to the commander's and pilot's suits by flexible hose at the suit ventila-
tion fitting.
The EES face area is separated from the rest of the suit by a barrier
that seals around the face. The barrier exhalation valve exhales gas into
the torso area. From the torso area, the air and exhaled gas exit through
a chest mounted pressure controller. When the suit ambient pressure low-
ers to 165 to 175 mmHg (3.2 to 3.4 psi), the controller closes to maintain
suit pressure at this level.
The EES also has a communication system.
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 32 of 33
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ANTIGRAVITY SUIT
The antigravity suit (AGS) is a separate unit but it cannot be operat-
ed without the EES in the development flight tests.
The AGS prevents pooling of body fluids and aids in maintaining circu-
lating blood volume. Pooling of body fluids can occur when high "g" loads
are imposed on the body. It is particularly noticeable after crew members
have had more than three days of zero "g" activity.
For the development flight tests, bladders in the AGS receive oxygen
from the power reactant storage distribution cryogenic system, ECLSS ARS
emergency oxygen system, or the ejection seat emergency oxygen supply.
When the bladders of the AGS are activated, pressure is applied to the
crew member's lower extremities and to the abdomen to prevent the pooling
of body fluids.
The AGS weighs 2.2 kilograms (5 pounds).
The AGS will be worn for entry in the operational flights, and the con-
figuration will be supplied at a later date.
Contractors involved with the ECLSS are: Hamilton Standard Division of
United Technologies Corp., Windsor Locks, CT (atmospheric revitalization,
Freon-21 coolant loops, heat exchangers, cabin fan assembly, debris trap,
CO2 absorber, humidity control heat exchanger, avionics fan, accumulators,
flash evaporators, water management panel, EVA life support system and
EMU's); Carlton Controls, East Aurora, NY (atmospheric revitalization pres-
sure control subsystem and airlock support components); Aerodyne Controls
Corp., Farmingdale, NY (water pressure relief valve, oxygen check valve);
Aeroquip Corp., Marman, Los Angeles, CA (couplings, clamps, retaining
straps, and flexible air duct); AiResearch Manufacturing Co., Garret
Corp., Torrance, CA (ground coolant unit); Anemostat Products, Scranton PA
(cabin air diffuser); Arrowhead Products Division of Federal Mogul, Los
Alamitos, CA (coupling, flex air duct, flexible connector, connector drain
system convoluted bellows); Brunswick, Lincoln, NE (atmospheric revitaliza-
tion oxygen, nitrogen tanks); Brunswick, Circle Seal, Anaheim, CA (water
relief valve, water check valve); Brunswick Wintek, El Segundo, CA (water
relief valve, water check valve, water filter); Consolidated Controls, El
Segundo, CA (unidirectional/bidirectional shutoff valve, water solenoid
latching valve); Cox and Co., New York, NY (water relief valve, vent noz-
zle and port heater, water boiler steam vent line heater); Dynamic Corp.,
Scranton, PA (cabin diffuser); Fairchild Stratos, Manhattan Beach, CA (am-
monia boiler); General Electric, Valley Forge, PA (waste collector); Metal
Bellows Co., Chatsworth, CA (potable and waste water tanks, flex metal
tubes); RDF Corp., Hudson, NH (temperature sensor/transducer); Symetrics,
Canoga Park, CA (Freon fluid disconnects, water boiler quick disconnects);
Seaton Wilson, Inc., subsidiary of Systron-Donner, Burbank, CA (water and
coolant system quick disconnects); Tavis Corp., Mariposa, CA (Freon flow
PRESS INFORMATION
SPACE SHUTTLE TRANSPORTATION SYSTEM
March 1982
Rockwell International
SPACE SHUTTLE SPACECRAFT SYSTEMS
ENVIRONMENTAL CONTROL AND LIFE SUPPORT SYSTEM Page 33 of 33
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meter); Tayco Engineering, Long Beach, CA (urine, waste water, O2, N2
waste dump); Titeflex Division, Springfield, MA (water coolant flex line);
Vacco Industries, El Monte, CA (potable water inline pressure relief
valve); Vought Corp., Dallas, TX (radiators and flow control assembly).
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