Engineering topics

Lawrence W Barrett

Publications and source records attributed to Lawrence W Barrett.

2 records

NASA NTRS2026

Equivalent System Mass Comparison of ECLSS CO2 Removal Technologies

This project employs equivalent system mass (ESM) analyses to evaluate and compare state-of-the-art spacecraft CO2 removal systems. The ESM methodology converts sizing characteristics such as volume, power, and cooling requirements into a unified metric of mass, allowing for simple quantitative comparison of equipment impacts on a system level. Comparison of six high TRL technologies – the Carbon Dioxide Removal System (CDRS), Thermal Amine Scrubber (TAS), Carbon Dioxide Removal Assembly (CDRA), Four-Bed CO2 Scrubber (4BCO2), CO2 and Humidity Control Swing Bed (CHC), and the Carbon Dioxide Removal by Ionic Liquid Sorbent (CDRILS) – was achieved using an existing ESM spreadsheet tool that formerly ranked such technologies for consideration on Gateway. Fidelity of the tool was increased through revision with the most up-to-date sizing and performance data for each technology. ESM values were then estimated using NASA-supplied Lunar, Martian, and low-Earth orbit habitat infrastructure costs. This paper details the ESM approach used, lists major performance variables for each CO2 removal option, and summarizes conclusions of the technology comparison. The results are intended to act as a guide to assist programs in their selection of CO2 technologies best suited for a specific vehicle or mission.

Madeleine C Oliver↗

NASA NTRS2023

First Principles Modeling of the Thermal Amine Scrubber Flight Experiment’s Chemical Performance

The removal of atmospheric CO2 from a spacecraft is of particular importance to NASA’s mission, and is an area of continual study and technological advancement. One of the more recent advancements has been with reusable sorbents being regenerated with a combination of heat and vacuum. One such technology is the Thermal Amine Scrubber (TAS) flight experiment on the ISS, though several others are currently flying or preparing to fly. A model was created of the TAS to predict chemical performance, using fundamental chemistry and physics based on principles rather than empirical relations. Since the physical laws are true across all conditions, such a model enables greater model accuracy outside the bounds of test data, and allows for virtual testing of the hardware at conditions that are prohibitively difficult or expensive to actually test. This paper details the model’s development, operation, and correlation to data from the flight unit. The model is then compared to a data set taken from the flight unit under different flow, CO2 partial pressure, and bed configuration conditions, resulting in only a 2% error. The equations and principles laid forth in this paper are applicable to a wide range of thermally regenerated sorbents, and additional models of a similar nature would allow for potentially the most straightforward and direct method of comparison of technologies available to date.

CO2 removal↗