a. It is NASA policy to: (1) Control measurement processes to ensure the accuracy of measurement results affecting safety and mission success. Functions and conditions requiring measurement controls are identified in Attachment A. (2) Establish and maintain traceability of measurement results by an unbroken chain of calibrations through the National Institute of Standards and Technology (NIST), or an institution recognized by NIST through international agreements, to the International System of Units (SI) when such units have been established. (3) Control the accuracy, reliability, and use of Measuring and Test Equipment (MTE) through the use of a calibration system compliant with the requirements of American National Standards Institute/National Conference of Standards Laboratories (ANSI/NCSL) Z540.3-2006 and applicable requirements of Society of Automotive Engineers (SAE) AS9100, subject to the clarifications and modifications provided in Attachment B of this NASA Policy Directive (NPD).