(S (S (SBAR (WHADVP (WRB When)) (S (BASENP (PRP it)) (VP (VBD flew) (PP (IN through) (BASENP (DT the) (NNS plumes)))))) (S (BASENP (PRP it)) (VP (VBD was) (NP (BASENP (NN 120) (NNS miles)) (PP (IN from) (NP (BASENP (DT the) (NN moon) (POS 's)) (NN surface))))))) (PERIOD .))