In 1999 Spectrolab completed design and qualification; and began production on the next generation of multijunction solar cell - a triple-junction GaInP/GaAS/Ge. With over 20% AM0 conversion efficiency at an operating temperature of 60 degreesC, this cell provides 8-11% more power than competing dual-junction designs in GEO orbit after 15 years (6x10(14) 1-MeV electron equivalence). Spectrolab is currently qualifying an improved triple-junction cell capable of delivering over 22% AM0 conversion efficiency under these same conditions, with a beginning-of-life operating efficiency of 27%.