 During 1979 , the unmanned Voyager 1 and Voyager 2 space probes made the first images of Amalthea , which resolved its surface . They also measured the visible and infrared spectra and surface temperature . Later , the Galileo orbiter completed the imaging of Amalthea 's surface . Amalthea provided the final satellite fly @-@ by for Galileo on 5 November 2002 , at a distance from the moon 's center of approximately 244 km ( 152 mi ) ( height about 160 – 170 km ) , permitting the moon 's mass to be accurately determined , while changing Galileo 's trajectory so that it would plunge into Jupiter in September 2003 , having finished its mission . In 2006 Amalthea 's orbit was refined by New Horizons spacecraft 's instruments . 
