THE OBJECTIVE OF THIS PROJECT IS TO SUPPORT THE DEVELOPMENT OF X-RAY MICROCALORIMETER SENSORS FOR THE ATHENA SATELLITE MISSION. THE ATHENA MISSION IS LED BY THE EUROPEAN SPACE AGENCY (ESA) AND WILL CONSIST OF AN X-RAY MIRROR AND TWO SCIENTIFIC INSTRUMENTS A WIDE-FIELD IMAGER AND A MICROCALORIMETER IMAGING SPECTROMETER. THE MICROCALORIMETER INSTRUMENT WILL MEASURE THE ENERGIES OF X-RAYS EMITTED OR ABSORBED BY WEAK AND EXTENDED ASTROPHYSICAL SOURCES WITH UNPRECEDENTED DETAIL. ATHENA IS SCHEDULED FOR LAUNCH IN THE LATE 2020S OR POSSIBLY EARLY 2030S AND THE UNITED STATES HAS AGREED TO PARTICIPATE AT A SUBSTANTIAL LEVEL IN THE DEVELOPMENT OF THE MISSION.