Condolences to Elsner family.
 
Norbert Elsner Norb was the principal investigator for numerous thermoelectric devices and materials programs.  Mr. Elsner was awarded a  DOE citation for major contributions to the Voyager I and II SiGe thermoelectric generators that are still functioning and recently left the Solar System after 30 years of operation!  He led a team of scientists in the identification and fix of the SiGe-insulation incompatibility between the SiGe thermoelectric alloys and the insulation materials. While at General Atomics he worked on SiGe-based alloys and their fabrication, the PbTe-based alloys, and TAGS in space designed generators of high specific power, skutterudites, and the selenide compounds (Nd,Gd)Se_1.5 and (Cu,Ag)2Se.  
He was principal contributor to the materials and process technology for the first nuclear-thermoelectric powered satellite (TRANSIT) using radiation coupling between the heat source and the converter.  He  also contributed significantly to fabrication, coating, and characterizing refractory (Mo, Ta, W) and noble (Pt, Rh) metals for containment of PuO2 which supported the development of nuclear batteries for satellites and heart pacemakers.  Mr. Elsner was also involved developing high temperature (800-900°C) metal-ceramic seals for long life thermionic power diodes and  made contributions to the development of thermophotovoltaic generators and low activation ceramic materials for the first walls of thermonuclear fusion reactors.
http://www.its.org/content/norbert-elsner-1933-2010