General Instructions For All Part Categories Dr. Kusum Sahu, Principal Parts Engineer, CODE 562, NASA/GSFC

EEE- INST-002: General instructions for all part categories.

EEE-INST-002 provides baseline criteria for selection, screening, qualification, and derating of EEE parts for use on NASA GSFC space flight projects.  It provides instructions for meeting three reliability levels of EEE parts requirements based on mission needs for 18 part categories including capacitors, connectors and contacts, crystals, crystal oscillators, passive fiber optics, filters, fuses, heaters, magnetics, hybrid microcircuits, monolithic microcircuits, plastic encapsulated microcircuits, electromagnetic relays, resistors, discrete semiconductor devices, switches, thermistors, and wire and cable. The instructions in this document shall be implemented when specified in GSFC space projects Statements of Work (SOWs), Mission Assurance Requirements (MAR), or their equivalents. Due to the dynamic nature of this document, users are advised to check the http://nepp.nasa.gov website prior to every usage to obtain the latest document revision.

EEE parts shall be processed in accordance with the detailed requirements for the applicable part types and quality levels specified in Sections C1 through W1 of EEE-INST-002.  Each section contains selection, screening, qualification, and derating tables.  All tests shall be performed in the order shown unless otherwise approved by the project.  Exceptions or additions to the requirements specified in any section shall be defined in the project MAR document.  Applicable part quality levels shall be as defined by the project in the MAR.  As a guide to project managers, design leads, and System Assurance Managers (SAMs), the following are typical mission characteristics applicable to each quality level:

Level 1:            Parts shall be selected and processed to this level for missions requiring the highest reliability and lowest level of risk.  Level 1 active parts shall be reviewed for radiation hardness, and radiation testing is required when information is not available. The typical mission duration for Level 1 programs is 5 years or greater.

Level 2:            Parts shall be selected and processed to this level for missions with low to moderate risk, balanced by cost constraints and mission objectives.  Level 2 active parts shall be reviewed for radiation hardness, and radiation testing is required when information is not available. The typical mission duration for level 2 programs varies from 1 to 5 years.

Level 3:            Parts represent inherently high risk or unknown risk because of the lack of formalized reliability assessment, screening and qualification. Also, there is little dependable data or flight history available for them as the continuous changes in design, materials and manufacturing processes may make the data on any particular LDC not applicable to another LDC.  Level 3 parts are intended for mission applications where the use of high-risk parts is acceptable.  Level 3 active parts shall be evaluated for radiation hardness, and radiation testing is required when information is not available. The typical mission duration for level 3 programs varies from less than 1 year to 2 years.

Part types that do not fall in to the 18 categories covered in this document shall be reviewed on a case-by-case basis using the closest NASA, DSCC or government controlled specification as a baseline. The review shall ensure that parts meet the reliability requirement of its intended application and shall cover the selection, screening, qualification and applicable derating. In the event a suitable government baseline specification does not exist, the user shall approach the project parts engineer to identify the parts expert who can provide information on the best available industry standards to develop procurement specifications that meet the reliability goals.