  ULTRASAT (ULtraviolet TRansient Astronomy SATellite) is a wide-angle space
telescope that will perform deep time-resolved surveys in the near-ultraviolet
spectrum. ULTRASAT is a space mission led by the Weizmann Institute of Science
and the Israel Space Agency and is planned for launch in 2025. The camera
implements backside-illuminated, stitched pixel sensors. The pixel has a
dual-conversion-gain 4T architecture, with a pitch of $9.5$ $\mu m$ and is
produced in a $180$ $nm$ process by Tower Semiconductor. Before the final
sensor was available for testing, test sensors provided by Tower were used to
gain first insights into the pixel's radiation tolerance. One of the main
contributions to sensor degradation due to radiation for the ULTRASAT mission
is Total Ionizing Dose (TID). TID measurements on the test sensors have been
performed with a Co-60 gamma source at Helmholz Zentrum Berlin and CC-60
facility at CERN and preliminary results are presented.
