Dynamic Modeling of ALS Systems

2003-01-2543

07/07/2003

Event
International Conference On Environmental Systems
Authors Abstract
Content
The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system.
Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.
Meta TagsDetails
DOI
https://doi.org/10.4271/2003-01-2543
Pages
20
Citation
Jones, H., "Dynamic Modeling of ALS Systems," SAE Technical Paper 2003-01-2543, 2003, https://doi.org/10.4271/2003-01-2543.
Additional Details
Publisher
Published
Jul 7, 2003
Product Code
2003-01-2543
Content Type
Technical Paper
Language
English