ISS Life Support Cooperation Network: A 2D Model of…

Overview of the Life Support System

The International Space Station (ISS) relies on a sophisticated life support system to maintain breathable air for its crew. This includes systems that remove carbon dioxide (CO2), which is a byproduct of human respiration and metabolic processes. The model presented here simulates the cooperation between two such systems: the US CDRA scrubber and the Russian Vozdukh scrubber, connected through an inter-module ventilation duct.

Each module in the simulation represents a distinct segment of the ISS with its own unique life support equipment. By toggling these systems on or off and adjusting fan flow rates, learners can observe how changes affect the overall atmospheric conditions within the station.

CO2 Scrubber Mechanisms

The CDRA (Crew and Crew Support Module) scrubber in the US lab uses a chemical process to absorb CO2 from the air, while the Vozdukh scrubber in the Russian segment employs a catalytic reaction. Both systems are designed to maintain acceptable levels of CO2 within the station’s atmosphere.

By studying these mechanisms through the simulation, one can gain insights into how different technologies and configurations interact to ensure a stable environment for astronauts.

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Mass-Balance ODE and Duct Flow Dynamics

The model employs ordinary differential equations (ODEs) to simulate the mass balance of CO2 within the station. This involves tracking the rate at which CO2 is produced by the crew, absorbed by the scrubbers, and circulated through the ventilation system.

Understanding these dynamics helps in predicting how changes in fan flow rates or scrubber status will affect the overall atmospheric conditions, ensuring that the station remains safe for habitation.

Real-World Applications

The principles demonstrated in this simulation are directly applicable to real-world space missions. Ensuring efficient and reliable life support systems is critical not only on the ISS but also for future long-duration space exploration, such as trips to Mars.

By optimizing these systems, mission planners can reduce the need for frequent resupply missions, thereby extending the duration of space missions while maintaining crew health.

Frequently asked questions

How does the simulation help in understanding life support systems on Earth?

While primarily designed for space applications, this model can also be used to understand and optimize environmental control systems in confined spaces like submarines or remote research stations.

What are the implications of having one scrubber fail during a mission?

If a scrubber fails, it could lead to an accumulation of CO2, potentially reaching levels that are harmful to the crew. The simulation helps in planning backup systems and contingency measures.

Can this model be used for other gases besides CO2?

The principles can be extended to other gases, but specific scrubber technologies would need to be adapted accordingly. This model focuses on CO2 due to its critical role in maintaining breathable air.

How does the simulation account for the crew's metabolic rate and activity levels?

The simulation includes a slider that allows users to adjust the total number of crew members, which indirectly accounts for variations in metabolic rates. Additional parameters could be added to more precisely model individual activities.

Try it live

Everything above runs in your browser — open ISS Life Support Cooperation Network — 2D and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open ISS Life Support Cooperation Network — 2D simulation

ISS Life Support Cooperation Network: A 2D Model of Atmospheric Management