A small team of technologists at NASA’s Stennis Space Center is gaining recognition for its expertise in designing, testing, and deploying capabilities that help critical systems operate more autonomously and efficiently.

The Stennis Autonomous Systems Lab team is focused on providing capabilities that can be used on ground systems, as well as those needed to enable sustainable exploration of the Moon and beyond. “This is a challenging but critical area of work,” said Duane Armstrong, chief of the Test Technology Branch in the Stennis engineering and Test Directorate.

An international conference of aerospace experts recently acknowledged the significance of the team’s efforts, recognizing Stennis Space Center for cutting-edge research in predictive maintenance and integrated systems health management (ISHM).

A collaborative paper by the Stennis Autonomous Systems Lab on how to implement health management capabilities into an existing high-pressure pump-based system was awarded top honors in March in the Predictive Maintenance/ISHM track by the international Institute of Electrical and Electronics Engineers (IEEE) Aerospace Conference. The paper focused on how to use system monitoring capabilities on the liquid nitrogen pump system at Stennis.

“This is a major recognition of the innovative work being done by a dedicated team of people at Stennis, working with research partners,” Armstrong said. “This team is focused on helping to improve the performance and reliability of Stennis systems and to lower their costs of operation.”

Systems management and maintenance is a critical need, particularly for a site such as Stennis that uses decades-old facilities to conduct large rocket stage and engine tests. For instance, the Stennis High-Pressure Gas Facility, which houses the liquid nitrogen pump system, has remained in constant operation since it was built in the 1960s. All maintenance and repair work on systems must be completing while the facility remains in operation.

There are several operating risks associated with high-pressure systems, such as the liquid nitrogen network at Stennis. Cavitation is one of the most common and damaging. It occurs when liquid in a system forms vapor cavities or bubbles that can cause serious damage to equipment when they implode. Pumps in such systems also suffer from lower output due to wear in valves and seals. Pumps used with super-low temperature cryogenic liquids develop leaks on the cold end of the assembly as well, requiring replacement of assembly components.

Predictive maintenance and ISHM capabilities would help in monitoring such a system and allowing issues to be addressed automatically or in more timely fashion. For instance, if a monitoring system could detect cavitation, it could automatically take steps to protect the pumps and equipment. Likewise, if the operational life of a pump’s cold end assembly could be determined, replacement parts could be ordered in a timely fashion.

However, installing such capabilities within a heritage system such as the High-Pressure Gas Facility poses particular challenges due to the age of the equipment and the lack of existing instrumentation and data that is needed.

In the recognized study, the Stennis Autonomous Systems Lab teamed with D2K Technologies to study whether – and how – such capabilities could be introduced in the Stennis liquid nitrogen system. The results are captured in the award-winning paper – “A Case Study on the Challenges and Opportunities for the Deployment of Prognostics and Health Management Capabilities in Existing Engineering Systems.”

The paper suggests innovative approaches, including the use of condition-based algorithms, to address concerns in a way that allows cavitation issues to be detected in real-time, as well as wear problems related to pump seals and components. Implementation of the suggested approaches would both protect equipment from damage and maximize the efficiency of the system.

The next step for Stennis is to implement the suggested capabilities into the liquid nitrogen system, whenever funding is available “If the approach can be proven at the Stennis High Pressure Gas Facility, it could serve as a prototype for similar systems,” Armstrong said. “It also could serve as a starting point to use the same sort of algorithmic approach to solve other system issues.”

Authors of the case study paper include Fernando Figueroa and Lauren Underwood with Stennis Space Center, joined by Federico Piatti and Mark Walker with D2K Technologies in Oceanside, California.

For information about Stennis Space Center, visit: www.nasa.gov/centers/stennis/