Marta Kristen ( born February 26, 1945 ) is an American actress. The naturally blonde haired Kristen is best-known for her role as
Guy Williams's and June Lockhart's beautiful daughter, Judy Robinson, in the television series Lost in Space ( 1965–1968 ). Marta played the part of the space family's eldest child, a mature "20 something woman" near the age group of the space pilot, played by
Mark Goddard. Her mature role allowed adult form fitting fashions and hairstyles, as shown in publicity photos of the TV series.