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The X-ray proportional counters on board the Near Earth Asteroid Rendezvous (NEAR) spacecraft have exhibited a resolution degradation and recovery phenomenon several times during the long cruise phase of the mission. The resolution is checked periodically by commanding an 55 Fe source into the window area. The degradation is seen as a low energy tailing of the 5.9 keV photopeak. Two events have occurred which provided good spectral data for better understanding the degradation phenomenon. In November 1997 a large solar particle event occurred that degraded the resolution and excited copper in the collimator. Eventually the detectors returned to normal. In January 1998 the spacecraft performed an Earth swingby gravity assist maneuver. The near Earth environment excited the magnesium and aluminum in the filter elements. The copper line was also produced. The NEAR spacecraft was launched in February 1996 and will rendezvous and orbit the asteroid 433 Eros in early 1999.

We present ground test and space flight data describing a single event anomaly that affects multiple bytes in a stacked DRAM module. A 12 Gbit solid state recorder containing 1,440 DRAM die experiences the anomalous events at a rate requiring testing of a large sample set of these modules.

We present a comparison of proton single event ground test results for two generations of MIL-STD-1773 fiber optic data bus interface modules. Single event upset rate prediction techniques for fiber optic data systems are also demonstrated and compared with in-flight space performance.