As launch vehicles become more and more complex, ensuring crew safety
and mission success becomes increasingly difficult but, according to
a recent technologies demonstration, help is on the way.

Identifying minor system errors before they become critical is one
key to developing safer, more reliable and less expensive space
vehicles. As part of NASA’s Space Launch Initiative (SLI), Honeywell,
Phoenix, and NASA Ames Research Center, located in California’s
Silicon Valley, recently demonstrated a suite of advanced diagnostic
tools known collectively as Integrated Vehicle Health Management
(IVHM). The milestone demonstration showed that separate technologies
could be integrated into a cohesive package that can handle realistic
problem scenarios that might be encountered in space.

“The Space Launch Initiative develops critical technologies, but it
also demonstrates the value of those technologies in a relevant
environment. Early demonstrations such as this are part of making
sure we are on the right track,” said William Kahle, IVHM project
manager at NASA Ames.

For the demonstration, realism was a must, so engineers looked at
various types of failures. Along with key subsystem failures,
cross-subsystem ‘sympathetic’ failures were tested. ‘Sympathetic’
failures occur when problems in one system affect the performance in
an unrelatTIONystem. To handle these types of failures and to build
system flexibility, the engineers used a variety of techniques.

“We recognized early on that the health management requirements of
RLVs (reusable launch vehicles) demand a range of diagnostic
approaches from model-based to expert system technologies,” said
Ronald Quinn, principal investigator for Honeywell.

To ensure realism, NASA Ames and Honeywell collaborated to develop
scenarios and select component technologies that will provide
relevant and significant results for the next generation of RLVs. In
one scenario, the IVHM systems were able to determine that an
indicated pressure-system failure in a propulsion subsystem actually
was caused by a failure in a power system control module.

“This is a realistic scenario that occurs often in complex systems
such as RLVs,” said Dr. Ann Patterson-Hine of NASA Ames. “It
demonstrates the need for a vehicle-wide health management system.”

NASA Ames, which leads the IVHM effort for the agency’s Space Launch
Initiative, also has developed other diagnostic and simulation tools.
Livingstone, a model-based reasoner, was selected to emulate the
propulsion health management system while TEAMS (Testability
Engineering and Maintenance System), a product of Ames’ Small
Business Innovative Research program, provided model-based reasoning
for the power system and provided vehicle level diagnoses. Spacecraft
Control Language was used to develop expert systems and the
architectural infrastructure that integrated these technologies. They
cover a wide range of capabilities necessary to satisfy the health
management needs for RLVs.

The Space Launch Initiative is NASA’s technology research and
development program aimed at dramatically increasing safety and
reliability and reducing the cost of a second-generation reusable
launch vehicle. All NASA field centers and the Air Force Research
Laboratory are actively participating in the Space Launch Initiative
and are vital to its success. NASA’s Marshall Space Flight Center in
Huntsville, Ala., leads the Space Launch Initiative for NASA’s Office
of Aerospace Technology.

Information about Integrated Vehicle Health Management and NASA’s
Space Launch Initiative can be found on the Internet at:

Information about Honeywell can be found on the Internet at: