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Difficult
Decisions Made Easier
Computer Technology
Originating Technology/NASA Contribution
NASA missions are extremely complex and prone to sudden,
catastrophic failure if equipment falters or if an unforeseen
event occurs. For these reasons, NASA trains to expect
the unexpected. It tests its equipment and systems in
extreme conditions, and it develops risk-analysis tests
to foresee any possible problems.
The Space Agency recently worked with an industry partner
to develop reliability analysis software capable of modeling
complex, highly dynamic systems, taking into account variations
in input parameters and the evolution of the system over
the course of a mission.
The goal of this research was multifold. It included performance
and risk analyses of complex, multiphase missions, like
the insertion of the Mars
Reconnaissance Orbiter; reliability
analyses of systems with redundant and/or repairable components;
optimization analyses of system configurations with respect
to cost and reliability; and sensitivity analyses to identify
optimal areas for uncertainty reduction or performance
enhancement.
Partnership
For this work, NASA turned to GoldSim
Technology Group LLC, of Issaquah, Washington, a privately held software
company that delivers software and services to help people
understand complex systems and make better decisions.
GoldSim, the company’s namesake simulation software, was
originally developed for long-term safety analyses of
nuclear waste disposal, and is currently used by the U.S.
Department of Energy and the U.S. Nuclear Regulatory Commission,
among others. It is the company’s flagship product and
is widely used for performance assessment in the nuclear
arena, most notably at the Yucca Mountain Project in Nevada,
the Nation’s first long-term geologic repository for spent
nuclear fuel and high-level radioactive waste.
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Artist’s
concept of the Mars Reconnaissance Orbiter (MRO)
during the critical process of Mars orbit insertion.
GoldSim software helped make this part of the
mission a success. |
The company worked with NASA through a Small
Business Innovation Research (SBIR) grant with the Jet
Propulsion Laboratory to develop and demonstrate a new module for
the GoldSim software: an integrated, total-system risk
and reliability analysis approach based on dynamic, probabilistic
simulation. This new module (the Reliability Module) added
features to the software to facilitate simulation of space
missions.
Previously, most NASA studies of mission risk and reliability
used a methodology known as fault tree analysis, which
was often difficult to implement for complex systems that
changed over time. Instead of using fault trees, the GoldSim
methodology actually simulates the behavior of the mission
components over the full duration of the mission, explicitly
representing how the various components evolve over time
and the probabilities involved. The analysis is intensive
and computes the possible ways that the mission may fail,
along with their probabilities.
This approach now provides a valuable new systems analysis
capability to complement current NASA systems analysis
approaches. In particular, it is useful for impact studies,
risk/cost/benefit analyses, risk/uncertainty analyses,
model integration, and model-based design/model-based
engineering.
The development of the new module marked the successful
completion of the NASA-funded research project to demonstrate
the suitability of the GoldSim software for evaluating
the risk and reliability of future NASA missions.
The company released the Reliability Module to the public
in September 2005.
Product Outcome
GoldSim is used to create computer models that simulate
the performance of complex systems in business, engineering,
and science. In general, the purpose of such models is
to simulate the future behavior of a system and then determine
what can be done to improve its performance. These models
are used to gain a diagnostic understanding of the system,
ask “what if” questions about it, and evaluate alternative
designs, policies, and plans. It is used by organizations
worldwide.
The software is highly graphical and extensible, able
to quantitatively represent the uncertainty inherent in
complex systems, and allows users to create compelling
models that are easy to communicate and explain to diverse
audiences. Users build a model in an intuitive manner
by literally drawing a picture (an influence diagram)
of their system. In a sense, GoldSim is like a “visual
spreadsheet” that allows users to graphically create and
manipulate data and equations. It moves beyond spreadsheets,
however, by making it much easier for users to evaluate
how systems evolve over time and predict their future
behavior.
The primary applications for the software fall into three
categories: engineered systems modeling, environmental
systems modeling, and business modeling.
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The
GoldSim software aids in uncertainty reduction
and performance enhancement by providing decision
makers with a highly graphical, multidimensional
analysis tool. This screen shot is a seemingly
simple depiction showing some of the elements
that came into play while planning the complex
orbital insertion of the Mars Reconnaissance Orbiter. |
For many complex engineered systems (such as space and
defense systems, industrial facilities, mines, power plants,
and computer networks), it is necessary to predict measures
such as the system’s reliability or risk. GoldSim can
be used to simulate the reliability and performance of
complex engineered systems over time.
The Reliability Module (the result of the NASA SBIR grant)
supports the software’s ability to perform engineering
systems analysis, as it consists of predicted reliability
metrics (e.g., reliability and availability) for the overall
system and for individual components within that system.
The Reliability Module can also be used to compute the
probability of specific consequences (e.g., catastrophic
failure of the system) to support risk analysis. GoldSim
catalogs and analyzes failure scenarios, which allows
for key sources of unreliability and risk to be identified.
GoldSim can also be used to create realistic models of
complex, real-world, multimedia environmental systems.
Users can explicitly represent the uncertainty inherent
in these systems, in order to carry out risk analyses,
evaluate potential environmental impacts, and make better
resource management decisions. According to the company,
GoldSim is, for this purpose, the premier tool in the
world for carrying out performance assessments of proposed
and existing radioactive waste management sites.
GoldSim is also useful for a wide range of other environmental
systems modeling applications, including water balances
and water quality management at mines and other constructed
facilities; municipal water resources management and planning;
the performance of existing or proposed landfills, hazardous
waste sites and engineered disposal facilities; environmental
impacts associated with various mine development and closure
options; the transport and fate of contaminants in aquifers,
wetlands, lakes, and other ecosystems; transmission of
infectious diseases; and the transport and fate of pharmaceuticals
and other compounds within biological systems.
Another arena where GoldSim has found a home is in business
modeling. Most business modeling today relies on the use
of spreadsheets and/or project management software to
create project schedules, do simplified risk analysis
calculations, carry out cost and revenue projections,
and perform other simple financial analyses. Although
such tools are useful and applicable in many cases, they
generally do not have the ability to represent the complex
dynamics and uncertainties present in real-world business
systems. As such, the projections produced by these tools
often do not provide a realistic representation of the
future. This can lead to poor decisions. GoldSim provides
users with the ability to transform business modeling
into a more quantitative, rational, and defensible analysis.
It provides business planners with the tools to evaluate
alternative strategies and policies, and identify those
that offer the greatest potential for success; determine
the optimal portfolio of projects, resources, and/or investments;
develop program plans that provide the highest likelihood
of meeting objectives on time and under budget; and evaluate
risks, and then identify cost-effective preemptive measures
and contingency plans that minimize adverse impacts. Business
planners can also use this software to evaluate the performance
of supply chains or design and evaluate financial instruments.
All of the engineering systems modeling, environmental
systems modeling, and business modeling applications can
benefit from the collaborative research performed by NASA
and GoldSim. In fact, the company sees this software being
beneficial in even more arenas.
“We also think it has a lot of potential in other fields
where risk and reliability are important—areas such as
defense, automotive, and electronics. It isn’t just a
matter of doing risk calculations; it’s important to really
understand the sources of risk or unreliability in order
to be able to design optimal solutions. That’s what our
GoldSim software is all about,” said Ian Miller, president
of GoldSim.
GoldSim® is a registered trademark of GoldSim Technology
Group LLC.
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