Engineering topics

VanWie, Michael

Publications and source records attributed to VanWie, Michael.

4 records

NASA NTRS2010

Second Generation International Space Station (ISS) Total Organic Carbon Analyzer (TOCA) Verification Testing and On-Orbit Performance Results

The Total Organic Carbon Analyzer (TOGA) is designed to autonomously determine recovered water quality as a function of TOC. The current TOGA has been on the International Space Station since November 2008. Functional checkout and operations revealed complex operating considerations. Specifically, failure of the hydrogen catalyst resulted in the development of an innovative oxidation analysis method. This method reduces the activation time and limits the hydrogen produced during analysis, while retaining the ability to indicate TOC concentrations within 25% accuracy. Subsequent testing and comparison to archived samples returned from the Station and tested on the ground yield high confidence in this method, and in the quality of the recovered water.

Bentley, Nicole L.↗

NASA NTRS2009

Development of the Second Generation International Space Station (ISS) Total Organic Carbon Analyzer (TOCA)

The second generation International Space Station (ISS) Total Organic Carbon Analyzer s (TOCA) function is to monitor concentrations of Total Organic Carbon (TOC) in ISS water samples. TOC is one measurement that provides a general indication of overall water quality by indicating the potential presence of hazardous chemicals. The data generated from the TOCA is used as a hazard control to assess the quality of the reclaimed and stored water supplies on-orbit and their suitability for crew consumption. This paper details the unique ISS Program requirements, the design of the ISS TOCA, and a brief description of the on-orbit concept-of-operations. The TOCA schematic will be discussed in detail along with specific information regarding key components. The ISS TOCA was designed as a non-toxic TOC analyzer that could be deployed in a flight ready package. This basic concept was developed through laboratory component level testing, two moderate fidelity integrated system breadboard prototypes, a flight-like full scale prototype, as well as lessons learned from the inadequacies of the first unit. The result: a new TOCA unit that is robust in design and includes special considerations to microgravity and the on-orbit ISS environment. TOCA meets the accuracy needs of the ISS Program with a 1,000 to 25,000 g/L range, accurate to within +/-25%.

Clements, Anna L.↗

NASA NTRS2005

Learning from Failures: Archiving and Designing with Failure and Risk

Identifying and mitigating risks during conceptual design remains an ongoing challenge. This work presents the results of collaborative efforts between The University of Missouri-Rolla and NASA Ames Research Center to examine how an early stage mission design team at NASA addresses risk, and, how a computational support tool can assist these designers in their tasks. Results of our observations are given in addition to a brief example of our implementation of a repository based computational tool that allows users to browse and search through archived failure and risk data as related to either physical artifacts or functionality.

VanWie, Michael↗

NASA NTRS2005

An Analysis of Risk and Function Information in Early Stage Design

The concept of function offers a high potential for thinking and reasoning about designs as well as providing a common thread for relating together other design information. This paper focuses specifically on the relation between function and risk by examining how this information is addressed for a design team conducting early stage design for space missions. Risk information is decomposed into a set of key attributes which are then used to scrutinize the risk information using three approaches from the pragmatics sub-field of linguistics: i) Gricean, ii) Relevance Theory, and Functional Analysis. Results of this linguistics-based approach descriptively account for the context of designer communication with respect to function and risk, and offer prescriptive guidelines for improving designer communication.

Barrientos, Francesca↗