Ashok K. Sharma, NASA GSFC, Code 562
Ashok.K.Sharma.1@gsfc.nasa.gov

This issue of the NASA Electronic Parts and Packaging Program (NEPP) EEE Links is focused on extreme environment electronics; it contains summaries, abstracts, and test reports from the NEPP Group. Research from NASA GSFC, JPL, GRC, LaRC, and MSFC is represented, as well as from universities and contractor partners.

NASA has ongoing programs and missions planned for the future that require operation of planetary probes, payloads, and instruments over a wide temperature range, such as below -125 °C for the Martian environment to over 500 °C for the Venusian atmosphere. Microsystems composed of microelectronics and micro-electro-mechanical systems (MEMS) are being considered increasingly for high temperature applications such as aerospace engine monitoring and space exploration. NASA projects such as Next Generation Space Telescope (NGST), Mars Exploration Rover (MER), and Mars Smart Lander (MSL) require operation at very low temperatures—all the way down to cryogenic temperatures (e.g., 4.2 °K for sensor elements). A probe launched for Asteroid Nereus will be exposed to temperatures ranging from -180 °C to 100 °C. Reliable cold electronic systems capable of operating at cryogenic temperatures will be needed for many future NASA space missions, including deep space probes and spacecraft for planetary surface explorations.

The military specifications for microelectronic components used in probes and planetary exploration mission flight hardware encompass a maximum operating temperature range of -55 °C to +125 °C. Commercial-off-the-shelf (COTS) devices, which are also being used increasingly in these missions, have a specified operating temperature range of only -30 °C to +85 °C. Hazards posed by extreme environments entail high doses of cumulative radiation (total ionizing dose), as well as single event phenomenon (SEP) that includes single event upset (SEU), single event latchup (SEL), and single event gate rupture (SEGR). In addition, various elements of the environment, such as low temperature and total dose exposure, can combine to create even greater problems. Therefore, it is of great interest to the NASA community to evaluate performance and reliability characteristics of military/commercial temperature range devices over extreme environments and provide guidelines for applications, packaging, and risk mitigation techniques.

Many of these extreme environment application challenges and reliability issues are being addressed by the NEPP program. The NEPP Cold Temperature Electronics Group including JPL, GRC, and GSFC has performed evaluation on several technologies and part types of interest. For example, GRC is currently investigating the effects of cryogenic temperature and thermal cycling effects on DC-DC converters that are widely used in space power systems for power management, conditioning, and control. In addition to the DC-DC converter testing, GRC has also tested COTS plastic encapsulated voltage references and power switching devices. GSFC has performed low/high temperature testing on MEMS accelerometers, thermally actuated micromachined relays, evaluation of data retention and imprint characteristics of FRAMs under environmental stresses, and characterization of extreme temperature effects on plastic encapsulated voltage reference microcircuits. JPL has performed extreme low temperature characterization of rad-hard and commercial quad receivers and A-D converters.

For additional details, see the full report posted on the NEPP Web site at
http://nepp.nasa.gov/index_nasa.cfm/619/09FE38FB-17FA-4D11-8CD3C71ABE5B8D16/