Creare has developed and demonstrated a high-efficiency, high-capacity reverse-Brayton cryocooler for zero-boil-off storage and liquefaction of hydrogen at 20 K.  Our cooler provides over ten times more refrigeration at 20K than competing coolers and is a key enabling technology for future space exploration missions.  Our paper at the 2020 International Cryocooler Conference describes this ground-breaking technology.