This episode's headline: Star Trek; Bogus Ballot?; Waste Not; Back to the Future. The guests include SAM KELLER, NASA; SEN. CONNIE MACK, [R] Florida; SEN. RICHARD LUGAR, [R] Indiana; SEN.CHRISTOPHER DODD, [D] Connecticut; AMB. JUAN SOSA, Panama; CORRESPONDENTS: CHARLES KRAUSE; TOM BEARDEN; ESSAYIST: BILL BAROL. Byline: In New York: ROBERT MacNeil; In Washington: JAMES LEHRER