<Li> Maxwell Jenkins as Will Robinson, the 11 - year - old son and youngest child of Maureen and John Robinson . He forms a tight bond with the Robot, whom he saves from destruction during a forest fire . </Li> <Li> Taylor Russell as Judy Robinson, Maureen's 18 - year - old biracial daughter and eldest child . She is a mission doctor, having received accelerated medical training . </Li> <Li> Mina Sundwall as Penny Robinson, the 15 - year - old daughter and middle Robinson child . </Li> <Li> Ignacio Serricchio as Don West, a mechanic who also smuggles luxury goods . He has a chicken named Debbie, which he claims to be lucky . </Li>

Who played penny in lost in space 2018