(S (S (BASENP (NNP NASA)) (VP (VBZ has) (VP (VP (VBN completed) (NP (BASENP (DT a) (JJ major) (NN test)) (PP (IN of) (BASENP (DT a) (ADJP (NN 20-meter) (NN square)) (JJ solar) (NN sail))))) (COMMA ,) (S (VP (VP (VBG marking) (NP (DT a) (QT (DQL ``) (BASENP (JJ crucial) (NN milestone)) (DQR '')))) (PP (IN in) (BASENP (NN space) (NN propulsion) (NN technology)))))))) (PERIOD .))