The Metrology and Calibration (MetCal) Working Group (MCWG) held its annual Technical Interchange Meeting (TIM) April 25-28, 2022, at NASA Wallops Flight Facility. Agency MetCal representatives, calibration laboratory managers, metrologists and other experts from associated fields across all of NASA’s 10 field centers, and two component centers, met in-person and virtually at this hybrid event to discuss technical challenges, best practices and improvements related to the agency’s MetCal program.

“The MetCal working group’s focus on information sharing, mentoring and continuous improvement was undeterred by the COVID-19 quarantine and they were excited to return to their practice of hosting an annual face-to-face meeting,” said Jeannette Plante, Quality program executive. “Though the MetCal function varies in execution across the agency, some centers hosting internal calibration labs, some not, some reporting to Engineering Directorates, and some reporting to SMA Directorate, they are a highly functioning working group and have shepherded significant process improvements almost entirely through volunteer efforts. The wide range of topics covered during the meeting demonstrated the strong engagement of its members and the complexity of the tasks they are responsible for in their daily work.”

During the meeting, members from calibration laboratories at Wallops and Marshall Space Flight Center shared their experiences from gaining International Organization for Standardization (ISO) 17025 accreditation for their calibration labs. Accreditation is a formal process where the calibration laboratory demonstrates compliance with all Quality Management Systems requirements, along with technical requirements, to ensure that the laboratory is equipped to perform tests and calibration activities. The accrediting body then issues a “scope of accreditation,” which details the competencies demonstrated by the calibration laboratory.

The MCWG also reviewed the results of the round-robin Performance Testing (PT) program conducted over the last year at the 10 NASA field centers and two component centers. Measuring and Test Equipment (MTE) artifacts, provided by the National Association of Proficiency Testing and managed by the MCWG, are sent to NASA field labs for a standard calibration. Results are analyzed and compared across the agency to optimize measurement processes used to calibrate MTE.

Over the course of the meeting, the group also reviewed a failure analysis report documenting hardware failures and repairs associated with an agency MTE asset, the Programable Josephson Voltage Standard (PJVS). This intrinsic standard utilizes a cryoprobe and cryochip that are cryogenically cooled in liquid helium. At this temperature, the cryochip enters a quantum conducting state in which its Josephson Junctions generate a “supercurrent” that flows continuously with no voltage applied. NASA purchased a new PJVS cryoprobe and cryochip from the National Institute of Standards and Technology (NIST) in 2020. (See “NASA’s Continued Use of PJVS for Calibrations Ensures Peak Accuracy” for more information.) The PJVS system is shipped across the agency to calibrate the laboratories’ Direct Current voltage standards. Between May 2020 and June 2021, the system experienced four hardware failure events. NIST was able to determine the cause of a probe failure to a connector and mitigated the recurrence with a new breakout box and revised operation procedures. The other three failures were attributed to the protective foam in the shipping container that was addressed by replacing with a lower density foam.

Other sessions throughout the week included

• A Subject Matter Expert from Langley Research Center presented unique procedures to characterize Wind Tunnel Balances used to measure aerodynamic forces.
• The Marshall Metrology and Calibration Laboratory personnel shared their experiences with the laboratory’s new state-of-the-art Master Scanner that is used for dimensional calibration of thread gages.
• The Training Group presented drafts of the MTE selection and use courses that are intended for MTE users.
• The PT Corrective Action Group discussed a proposed process to document recommendations and Corrective Actions to address data outliers during testing.
• The NASA Electrostatic Discharge (ESD) Working Group chair led the group on a discussion of the changes to ESD industrial standard American National Standards Institute/ESD S20.20 and how it could affect NASA operations and hardware.

The MetCal program is managed by the Office of Safety and Mission Assurance (OSMA) at NASA Headquarters. The MCWG, a function of this program, facilitates implementation of the MetCal program across NASA. The working group includes a NASA representative from each center and facility. Lab managers, metrologists, support personnel and contractors from all NASA-internal calibration labs actively participate in MCWG activities. The MCWG provides a forum to promote the development of agency requirements, guidance and tools for effective MetCal program implementation in accordance with NASA-STD-8739.12, Metrology and Calibration. Specific information about the 2022 MCWG TIM and its topics can be obtained by reaching out to a local MetCal representative. (Find a local Point of Contact in the People section of the Metrology and Calibration program website.)