 Dactyl is an " egg @-@ shaped " but " remarkably spherical " object measuring 1 @.@ 6 by 1 @.@ 4 by 1 @.@ 2 kilometres ( 0 @.@ 99 mi × 0 @.@ 87 mi × 0 @.@ 75 mi ) . It was oriented with its longest axis pointing towards Ida . Like Ida , Dactyl 's surface exhibits saturation cratering . It is marked by more than a dozen craters with a diameter greater than 80 m ( 260 ft ) , indicating that the moon has suffered many collisions during its history . At least six craters form a linear chain , suggesting that it was caused by locally produced debris , possibly ejected from Ida . Dactyl 's craters may contain central peaks , unlike those found on Ida . These features , and Dactyl 's spheroidal shape , imply that the moon is gravitationally controlled despite its small size . Like Ida , its average temperature is about 200 K ( − 73 ° C ; − 100 ° F ) . 
