Projects & Publications

Aerospace

Mars 2020 Mission Safety and Risk Assessment
Integrated Model-Based Fault-Management System Design
Development of Framework for the Validation and Verification of Model Based and Adaptive Control Systems
Commercial Crew Program Risk Assessment.
Update of NASA Probabilistic Risk Assessment Procedure Guide
Mars Science Laboratory Mission Safety and Risk Assessment
Pluto New Horizons Mission Safety & Risk Assessment
Development of NASA Probabilistic Risk Assessment Procedure Guide and Training Courses
Mars Exploration Missions Safety & Risk Assessment
New Horizons Pluto & Kuiper Belt Mission Safety & Risk Assessment
Automated FMECA& Diagnostic/ Prognostic Optimization Analysis
Aircraft probabilistic Risk Assessment Methodology (APRAM)
Application of Dynamic Flow Graph Techniques for Safety Analysis & Testing of Space Systems Software
Development & Tools for Software Safety Analysis in Space Systems Applications

Nuclear Systems

Development of Tools for Safety Analysis of Control Software in Advanced Reactors
Advanced methods for modeling team effects on control-room operator performance in real time
Evaluation of Work Processes at Nuclear Power Plants
Accident Management Advisor System (AMAS)

Our Publications

Context-based Software Risk Modeling: A Recommended Approach for Assessment of Software Related Risk in NASA Missions

June 29, 2012December 8, 2020 ASCA Inc. Publications, Software Safety

Software is a key component of modern space systems, which controls and monitors the functions of a range of electronic and mechanical devices. In essence, software provides the “brains” for the execution of all launch vehicle and space vehicle functions. While complex functionality may be welcome on one hand, software complexity may introduce more opportunity […]

Probabilistic Risk Assessment Procedures Guide for NASA Managers and Practitioners Contribution

December 11, 2011December 8, 2020 ASCA Inc. Aerospace Systems Risk & Reliability, Publications, Risk Analysis Methods

Probabilistic Risk Assessment (PRA) is a comprehensive, structured, and logical analysis method aimed at identifying and assessing risks in complex technological systems for the purpose of cost-effectively improving their safety and performance. NASA’s objective is to better understand and effectively manage risk, and thus more effectively ensure mission and programmatic success, and to achieve and […]

NASA Risk Management Handbook Contribution

November 11, 2011December 8, 2020 ASCA Inc. Aerospace Systems Risk & Reliability, Publications, Risk Management

The purpose of this handbook is to provide guidance for implementing the Risk Management (RM) requirements of NASA Procedural Requirements (NPR) document NPR 8000.4A, Agency Risk Management Procedural Requirements [1], with a specific focus on programs and projects, and applying to each level of the NASA organizational hierarchy as requirements flow down. This handbook supports […]

Extension of CAFTA with Dymonda Module to Analyze Dynamic Accident Scenarios

March 17, 2011December 8, 2020 ASCA Inc. Dynamic Flowgraph Methodology (DFM), Nuclear Powerplant Safety, Publications, Risk Analysis Methods

This paper discusses ASCA’s experience in applying the Dynamic Flowgraph Methodology (DFM) to a space propulsion system problem specified by the Idaho National Laboratory (INL). This problem serves as a benchmark for comparing and evaluating the capabilities of advanced Probabilistic Risk Assessment (PRA) tools that are suitable for the risk analysis of future space systems. […]

A Benchmark Implementation of Two Dynamic Methodologies for the Reliability Modeling of Digital Instrumentation and Control Systems

February 11, 2009December 8, 2020 ASCA Inc. Nuclear Powerplant Safety, Publications, Risk Analysis Methods

Two dynamic methodologies, dynamic flowgraph methodology (DFM) and the Markov/Cell-tocell mapping technique (CCMT), are implemented on the benchmark Digital Feedwater Control System (DFWCS) specified in NUREG-6942, “Dynamic Reliability Modeling of Digital Instrumentation and Control Systems for Nuclear Reactor Probabilistic Risk Assessments,” to demonstrate how an existing nuclear power plant probabilistic risk assessment (PRA) can incorporate a […]

A Benchmark System for Comparing Reliability Modeling Approaches for Digital Instrumentation and Control Systems

January 11, 2009December 8, 2020 ASCA Inc. Nuclear Powerplant Safety, Publications, Risk Analysis Methods

There is an accelerating trend to upgrade and replace nuclear power plant analog instrumentation and control systems with digital systems. While various methodologies are available for the reliability modeling of these systems for plant probabilistic risk assessments, there is no benchmark system that can be used as the basis for methodology comparison. A system representative […]