Reliability Engineering

 

Early explorers launched their wooden ships toward terra incognita, recognizing that their ventures entailed a high level of risk. Today's explorers craft complex equipment, which must meet stringent performance requirements in a hostile environment over the span of many years. A spacecraft designer must balance the advantages of adding an extra, redundant assembly against the additional weight and cost penalty. Also, customers increasingly demand that spacecraft be built at lower cost and with a shorter development schedule - and without a corresponding increase in mission risk.

Northrop Grumman is well versed in the techniques for ameliorating hardware design defects, which may cause catastrophic spacecraft failure or mission degradation. In support of most post-Voyager JPL projects, our staff has conducted reliability prediction modeling, failure mode and effects analysis (FMEA), fault tree analysis, parts stress analysis, worst-case analysis, failure trend analysis, and other engineering analyses for assuring mission success.

Our skills in using a variety of automated tools have been honed in the high radiation environment of Jupiter and in the deceleration shock of a Martian landing. For example, our staff is extremely proficient in the use of CadenceŽ for circuit board design and layout. Automated tools developed by Northrop Grumman personnel for JPL include:

  • A Java software program employing an easy-to-use, web browser user interface for analysis of worst case part parameters
  • An on-line intranet "knowledge base" for mechanism design issues
  • An ORACLEŽ data management system for failure reporting, tracking, and analysis
To resolve mission critical problems with current flight programs and to prevent their recurrence on future missions, Northrop Grumman is capable of identifying failure modes and failure mechanisms - occurring during ground testing and in flight - for the full gamut of electronic, mechanical, and optical assemblies.

Northrop Grumman personnel have processed thousands of official JPL anomaly reports to determine the need for design changes or other corrective action - with follow-up to track the issues to closure. Design reviews have been conducted with Northrop Grumman support at an early stage of design maturity, when problem correction remains cost effective. For JPL's largest military computer design project, we were entrusted with chairing the failure review board and running the problem/failure management center. Northrop Grumman has been commended for contributing expertise that greatly improved the effectiveness of the JPL Lessons Learned Committee in preserving NASA's engineering knowledge base.

Northrop Grumman has also supported high-reliability parts screening and part procurement activities. For several years, we have prepared a worst-case database of electrical and electromechanical piece parts for several projects, including the Cassini mission to Saturn, the Multi-Angle Imaging Spectroradiometer (MISR), and the Atmospheric Infrared Sounder (AIRS). For most flight projects, Northrop Grumman has served as a central resource for component parts variation data, as well as maintaining system data and system performance documentation.

An emerging role for Northrop Grumman involves the qualification of advanced technologies for the development of a new fleet of microspacecraft.
The next generation of very small spacecraft will use new, untested materials and components that are vulnerable to forces that their multi-ton predecessors could tolerate. Northrop Grumman is helping to verify the reliability of promising but unproven equipment and processes for spacecraft miniaturization. We have helped to design a unique test fixture capable of simulating pyrotechnic shock to high levels, and designed a shake test fixture for an ion engine, which will replace chemical rockets for long duration spaceflight missions. A long term Northrop Grumman goal is support of this nation's efforts to design a "spacecraft on a chip."