<P> Roberts decided late in the season to stay for one more year . This, plus the cast's concern that replacement of a regular character might create a threatening precedent, cost Williams the role . </P> <P> In 1965, Guy Williams returned to weekly television in the popular CBS science - fiction family series Lost In Space . </P> <P> Guy Williams played Professor John Robinson, expert in astrophysics and geology, who commanded the mission of the Jupiter 2 spaceship, taking his family in a voyage to colonize the Alpha Centauri star system . </P> <P> After Lost in Space, Guy Williams decided to retire in order to better enjoy his wealth, which had been largely generated by investments in several businesses, buying and selling on the stock market . When Guy had first visited Argentina in 1973 he was quite taken by the admiration and fascination the Argentine people expressed for him and his character of' El Zorro' . In return, Guy fell in love with the culture and people of Argentina . In the late 1970s he retired, except for personal appearances, to Recoleta, an upscale neighborhood of Buenos Aires . </P>

Who played john robinson on lost in space