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

SSP50065, theCHeCStoRSICD. Sample ports for
manual collection of water samples are provided to
facilitate off-line monitoring and analysis of processed
water, and for archiving of water samples.
Support Station Ingress
The DC supports the controlled, tethered entry into
the RS by a person in a pressurized spacesuit. The DC
supports repressurization from vacuum to the RS atmos-
pheric pressure at a nominal repressurization rate of
5 mmHg per sec. The maximum emergency repress-
urization rate is l0 mmHg per sec. In the event of an
emergency during an EVA, an unimpaired crew member
can reenter the AL within 30 min.
Distribute Gases to User Payloads
This capability is not presently required on the RS.
3.3.2 USOS ECLS Capabilities
The USOS ECLSS maintains the required atmos-
pheric composition for six crew members for CO 2
removal and trace contaminant removal, and TBD crew
members for metabolic 02.
The onboard equipment required for station survival
is serviceable in the pressure range of 60 to 107 kPa (450
to 800 mmHg, 8.7 to 15.5 psia). All onboard equipment
will also operate after being exposed to a minimum
pressure of 60 kPa (450 mmHg, 8.7 psia) after the
pressure has been restored to a minimum pressure
of 93.3 kPa (700 mmHg, 13.5 psia).
The USOS ECLSS capabilities are described below:
Control Total Atmospheric Pressure
The atmospheric total pressure is monitored over the
range of 0.0 to 110.6 kPa (0.0 to 827 mmHg, 0.0 to
16 psia) with an accuracy of +0.07 kPa (0.5 mmHg,
0.01 psia). The total pressure is maintained nominally
between 97.9 and 102.7 kPa (734 and 771 mmHg, 14.2
and 14.9 psia), with a minimum pressure of 95.8 kPa
(719 mmHg, 13.9 psia). The ppN2 is kept below 80 kPa
(600 mmHg, I 1.6 psia). N2 is stored in high-pressure
tanks (at least 850 L (30 ft3)) at pressures up to 23.4 MPa
(3400 psia). The tanks are recharged from the space
shuttle.
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Control Oxygen Partial Pressure
The atmospheric ppO2 is monitored over a range of
0.0 to 40 kPa (0.0 to 300 mmHg, 0.0 to 5.8 psia) with an
accuracy of +2 percent of full scale. The ppO2 is main-
tained between 19.5 and 23.1 kPa (146 and 173 mmHg,
2.83 and 3.35 psia) with a maximum concentration of
24. l percent by volume. 02 is added at a rate of 0.83 kg/
person/day (1.84 lb/persotVday) for four people and
1.08 kg/day (2.38 lb/day) for animal metabolic needs.
O2 is stored in high-pressure tanks (at least 850 L (30 ft3))
at pressures up to 23.4 MPa (3,400 psia). The tanks are
recharged from the space shuttle.
Relieve Overpressure
The atmospheric pressure is maintained below the
design maximum internal-to-external differential pressure.
Venting of atmosphere to space does not occur at less than
103.4 kPa (15.0 psid).
Equalize Pressure
The pressure differential between adjacent, isolated
volumes at 103.4 kPa (775.7 mmHg, 15.0 psia) and
99 kPa (740 mmHg, 14.3 psia) can be equalized to less
than 0.07 kPa (0.5 mmHg, 0.01 psia) within 3 min.
Respond to Rapid Decompression
A rapid decompression event can be detected prior to
the total pressure decreasing by 3.4 kPa (0.5 psia) based
on a hole size 1.27 to 5.08 cm (0.5 to 2.0 in) in diameter.
The USOS, except for the affected element, can be
repressurized from a minimum total pressure of 86.1 kPa
(12.5 psia) to a total pressure of 95.8 to 102.7 kPa (13.9
to 14.9 psia) and a ppO2 of 19.5 to 23.1 kPa (2.83 to
3.35 psia) within 75 hr, when supplied with gaseous O2
and N2.
Respond to Hazardous Atmosphere
Combustion products can be detected over the ranges
specified in table 7. The atmosphere of any pressurized
volume can be vented to space to achieve an atmospheric
pressure less than 2.8 kPa (20.7 mmHg, 0.4 psia) within
24 hr. PBA's provide 1 hr of continuous emergency
supply of 02 for each crew member through 02 ports or
15 min with emergency 02 tanks. Any single affected
element can be repressurized from space vacuum to a
total pressure of 95.8 to 98.6 kPa (13.9 to 14.3 psia) and a
ppO2 of 16.4 to 23.1 kPa (2.38 to 3.35 psia) within 75 hr.