( ( ( The ( ( most complex ) ( interplanetary spacecraft ) ) ) ( ever built ) ) ( , ( Cassini ( ( is ( ( a follow-on ) ( to ( ( the ( brief reconnaissance ) ) ( of ( Saturn ( performed ( by ( ( ( ( the ( Pioneer ( 11 spacecraft ) ) ) ( in 1979 ) ) and ) ( ( the ( Voyager ( 1 ( and ( 2 encounters ) ) ) ) ) ( of ( ( 1980 and ) 1981 ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (NP (DT The) (ADJP (RBS most) (JJ complex)) (JJ interplanetary) (NN spacecraft)) (ADVP (RB ever)) (VP (VBD built))) (, ,) (NP (NNP Cassini)) (VP (VBZ is) (NP (NP (DT a) (JJ follow-on)) (PP (TO to) (NP (NP (DT the) (JJ brief) (NN reconnaissance)) (PP (IN of) (NP (NP (NNP Saturn)) (VP (VBN performed) (PP (IN by) (NP (NP (NP (DT the) (NNP Pioneer) (CD 11) (NN spacecraft)) (PP (IN in) (NP (CD 1979)))) (CC and) (NP (NP (DT the) (NNP Voyager) (CD 1) (CC and) (CD 2) (NNS encounters)) (PP (IN of) (NP (CD 1980) (CC and) (CD 1981))))))))))))) (. .)))
The most complex interplanetary spacecraft ever built, Cassini is a follow-on to the brief reconnaissance of Saturn performed by the Pioneer 11 spacecraft in 1979 and the Voyager 1 and 2 encounters of 1980 and 1981.
(ROOT (S (NP (DT The) (NN voyager) (CD 1) (NN spacecraft)) (VP (VBD visited) (NP (NN saturn)) (PP (IN in) (NP (CD 1980)))) (. .)))