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Calcimator

Oxygen Generation Calculator

Calculate O2 requirements, electrolysis water needs, and power for crew oxygen generation in space habitats.

Inputs

Results

Daily O2 need (kg)

6.51

Total mission O2 (kg)1,172.6
Water for electrolysis (kg/day)7.3
Power needed (kWh/day)23.5
Emergency reserve (kg)45.6
Target ppO2 (kPa)21.3
How to Use This Calculator
  1. Enter the number of crew members and their daily oxygen consumption in kg/person/day.
  2. Set the oxygen generation method (electrolysis, chemical, stored).
  3. Input system efficiency percentage and power available in watts.
  4. Review the daily oxygen production rate in kg and power consumption.
  5. Size the backup stored oxygen supply to cover at least 48 hours of failure.

How the result changes with Crew size

Crew sizeDaily O2 need (kg)
1111.51
3636.51
6565.51
9090.51

What each input means

Crew size
Number of crew members.
Mission duration (days)
Total mission length.
Activity level (1-3)
1 = Rest (0.84 kg/day), 2 = Normal (1.0), 3 = Heavy (1.4).
EVA hours/week
Total crew EVA hours per week.

What each result means

Daily O2 need (kg)
Total daily oxygen consumption.
Total mission O2 (kg)
Total oxygen for entire mission.
Water for electrolysis (kg/day)
Daily water consumed for O2 production.
Power needed (kWh/day)
Electrical power for electrolysis.
Emergency reserve (kg)
7-day emergency O2 supply.
Target ppO2 (kPa)
Recommended O2 partial pressure.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Crew size = 6, Mission duration (days) = 180, Activity level (1-3) = 2, EVA hours/week = 6 = 4 input(s) provided
  2. Calculate Daily O2 need
    Daily O2 need = crewSize * o2RateKgPerDay + evaO2PerDay
    6.51 = 6.51
  3. Calculate Total mission O2
    Total mission O2 = round(dailyO2Kg * missionDurationDays * 10) / 10
    1172.6 = 1172.6
  4. Calculate Water for electrolysis
    Water for electrolysis = round(dailyO2Kg * (18 / 16) * 10) / 10
    7.3 = 7.3

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