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ECS Quick Reference Data

Atmosphere revitalization section (ARS)

  Cabin pressure 4.8 ± 0.2 psia (normal, steady-state)
  Suit circuit pressure  
    Cabin mode 4.8 ± 0.2 psia (may exceed 5.0 psia during powered flight)
    Egress mode 3.8 ± 0.2 psia (4.7 psia maximum during powered flight)
  Suit inlet temperature range With suit temperature control valve in full cold position, temperature ranges from +38 F to +65 F; in full hot position, from +42 F to 100 F.
  Cabin temperature +55 F to +90 F
  Relative humidity 40% to 80%
  Suit circuit fan flow At 4.8 psia - 36.0 pounds per hour (minimum)
At 3.8 psia - 28.4 pounds per hour (minimum)

Oxygen supply and cabin pressure control section (OSCPCS)

  Suit pressure increase First 1-psi increase may occur in less than 1 second. Each succeeding 1 -psi increase occurs in not less than 8 seconds.
  Cabin repressurization and emergency oxygen valve delivery rate  
    Descent mode 4 pounds per minute (maximum)
    Ascent mode 8 pounds per minute at 700 psia
  PLSS refill 0.91 pound/refill at 850 psia; can only be partially filled at lower pressures
  Cabin volume 235 cubic feet
  Dump valve bacteria filter efficiency Removes 95% of all bacteria larger than 0.5 micron
  Manual cabin pressure dump rate (without oxygen inflow) Dump valve in forward hatch, with bacteria filter, from 5.0 psia down to 0.08 psia in 310 seconds; overhead hatch, without filter, in 180 seconds; both valves, without filter, 90 seconds (Bacteria filter only flown on Apollo 11.)
  Number of cabin repressurizations 4 at 6.6 pounds each
  Cabin repressurization time 2 minutes
  Cabin pressure switch settings When cabin pressure drops to 3.7 to 4.45 psia, contacts close.
When cabin pressure increases to 4.40 to 5.0 psia, contacts open.
  Descent oxygen tank  
    Capacity 48.01 pounds at 2,730 psia and +700 F (residual oxygen:
1.0 pound)
    Burst pressure 4,500 psia
  Ascent oxygen tanks  
    Capacity 2.43 pounds (each tank) at 854 psia and +80 F (residual oxygen: 0.14 pounds (each tank) at 50 psia and +70 F
    Burst pressure 1,500 psia
  Bypass relief valve  
    Full flow pressure 3,030 psig (minimum) at +75 F
    Cracking pressure 2,875 psig (maximum) at +75 F
    Reseat pressure 2,850 psig (minimum) at +75 F
  Overboard relief valve  
    Full flow pressure 1,090 psig (maximum) at +75 F
    Cracking pressure 1,025 psig (minimum) at +75 F
    Reseat pressure 985 psig (minimum) at +75 F
  High-pressure regulator  
    Outlet pressure with primary and secondary regulators operating normally At inlet pressure of 1,100 to 3,000 psig and flow of 0. 1 to 4.0 pounds per hour, and inlet pressure of 975 to 1,100 psig and flow of 0.1 pound per hour, will regulate to 875 to 960 psig at 75 F

Water management section (WMS)

  Descent water tank  
    Capacity 333 pounds at 0.75 fill ratio
    Initial fill pressure 48.2 psia (maximum) at +80 F
    Residual water 6.66 pounds
    Pressure upon expulsion of all expellable water 11.0 psia (minimum) at +35 F
  Ascent water tanks  
    Capacity 42.5 pounds (each tank) at 0.75 fill ratio
    Initial fill pressure 48.2 psia (maximum) at +80 F
    Residual water 0.85 pound (each tank)
  Pressure regulator discharge pressure 0.5 to 1.0 psi above ARS gas pressure
  PLSS refill (each) 9.15 pounds of water

Heat transport section (HTS)

  Coolant Solution of ethylene glycol and water (35% and 65%, respectively, by weight) with inhibitors. Approximately 35 pounds of coolant is used in HTS.
  Coolant slush point -3 F
  Coolant pump rated flow
Flow rate of 222 pounds per hour (minimum) at +40 F, 30 psid, and 28-vdc input voltage
  Coolant pump bypass relief valve  
    Cracking pressure 33 to 36 psi
    Fully open pressure 39 psi
    Reseat pressure 1 psi less than cracking
  Coolant temperatures +29 F to +120 F
    Flow into primary sublimator +110 F (maximum)
    Flow out of sublimator +29 F to +36 F
    Flow into secondary sublimator +60.1 F'(minimum)
    Flow out of sublimator +47 F (maximum)
  Vacuum fill requirements HTS withstands internal pressure of 500 microns in sea-level ambient pressure environment.
  Primary and secondary coolant filters  
    Efficiency 35 microns absolute for primary; 45 microns absolute for
    Maximum bypass valve cracking pressure 0.4 psid for primary; 1.0 psid for secondary
  Coolant flow  
    Primary coolant loop 222 pounds per hour (minimum)
    Secondary coolant loop 222 pounds per hour (minimum)
  Cold plates  
    Coolant inlet operating temperature +32 F to + 100 F
    Coolant inlet operating pressure 5 to 45 psia
    Coolant inlet operating flow 12 to 85 pounds per hour, depending on cold-plate size


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