(S (S (S (BASENP (DT The) (NN problem)) (VP (VP (VBZ comes) (PP (IN after) (BASENP (DT a) (JJ separate) (NN incident)))) (BASENP (NN yesterday)))) (SBAR (WHADVP (WRB when)) (S (BASENP (DT a) (NN cockpit) (NN window) (NN cover)) (VP (VP (VBD fell) (PP (IN from) (BASENP (DT the) (NNP Orbiter)))) (COMMA ,) (S (VP (VBG damaging) (BASENP (JJ thermal) (NN protection) (NNS tiles)))))))) (PERIOD .))