Living Together in Space: The Design and Operation of the Life ...

4.0 Integrated Operation
The ECLS systems in the USOS and the RS are
physically separate, but during operation the hatches
in the FGB are open, and there is atmospheric transfer
between the segments. This atmospheric movement
carries water vapor and other atmospheric constituents,
which materially connect the ECLS systems. Therefore,
in addition to integrating hardware and functions, it is
necessary to integrate operation of the ECLS systems
and the responsibilities for performing the necessary
tasks.
Integrated operation involves connecting the different
segments, determining operational considerations, and
addressing integration concerns. At the time of writing,
details of the integrated operation of the ISS are being
resolved. The information presented here may change
and, therefore, serves as examples of the integration
concerns and responses.
4.1 Intermodule ECLSS Interfaces
Interfaces include those between the different seg-
ments and those between different components within a
segment. Interfaces between segments or modules include
structural/mechanical and utility connections consisting of
electrical power, atmosphere, structural and mechanical
loads, data, and commands. (Data and command interfaces
with the controllers on Earth are not considered in
this report.) Interfaces include atmospheric ducting be-
tween modules within a segment. Other examples are the
interfaces between the PFE's and the racks that may be
potential fire sources, and the connections for the PBA.
The interfaces that relate to ECLS are discussed in the
following paragraphs.
4.1.1 RS ECLS Interface With the USOS
Interfaces with the USOS through PMA-1 and
Node 1 include:
IMV Supply and Return
Atmosphere flows between the RS and the USOS
through the open hatches and ducts. Respirable air is
supplied from the FGB at a temperature of 18.3 to 28 °C
(65 to 82.4 °F), a flowrate between 60 to 70 L/sec (127
and 148 ft3/min), and a dewpoint between 4.4 and 13.9 °C
(40 and 57 oF).
Respirable air is returned to the FGB at a temperature
of 18.3 to 29.4 °C (65 to 85 oF), a flowrate between 60
to 70 L/sec (127 and 148 ft3/min), and a dewpoint
between 4.4 and 14 °C (40 and 57.2 °F). (The maximum
dewpoint temperature is based on analysis; the specified
maximum is 15.6 °C (60 °F).)
Water Transfer
The transfer from the USOS to the RS of water
condensed from atmospheric humidity is performed
manually using portable tanks (e_s containers).
4.1.2 RS-to-EVA ECLS Interface
The RS ECLS interfaces with the Orlan pressure suit
for servicing and checkout during EVA preparation and
support of the EVA crew during suited operations within
the DC.
4.1.3 USOS to APM, JEM, and MPLM
ECLS Interface
USOS interfaces with the APM and JEM (shown in
figures 17 and 18, respectively) include electrical power,
gaseous nitrogen, thermal energy, atmosphere, and water
return to the USOS. The USOS-to-APM physical and
functional interface requirements are described in SSP
41150. The USOS-to-JEM physical and functional
interface requirements are defined in SSP 41151, and
design implementations are described in SSP 42000. The
interfaces between the MPLM and the USOS are defined
in SSP 42007, and shown in figure 19.
ECLS interfaces with the USOS through Node 2
include:
Coolant Supply and Return
Low-temperature coolant for the ITCS is supplied
from the USOS at 0.6 to 5.6 °C (33 to 42 oF) and returned
to the USOS at 3.3 to 21 °C (38 to 70 °F), at a pressure of
124 to 689 kPa (1.24 to 6.9 bar, 18 to 100 psia) and at a
flowrate of 0 to 0.063 kg/s (0 to 8.33 lb/min).
Heat Load
The maximum heat load exchanged between Node 2
and the APM is _+200 W for sensible heat with no latent
heat transfer.
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