▁count down ▁dress ▁re he ars al ▁and ▁emer gency ▁training ▁dr ills . ▁After ▁the ▁arrival , ▁the ▁four ▁astr onaut s ▁spoke ▁to ▁rep or ters ▁at ▁the ▁run way ▁and ▁acknowled ged ▁the ▁historic ▁nature ▁of ▁the ▁final ▁sh utt le ▁mission . ▁" We ' re ▁incred ibly ▁proud ▁to ▁represent ▁the ▁final ▁flight ," ▁noted ▁the ▁commander , ▁Chris ▁Fer g us on . ▁During ▁the ▁training , ▁the ▁crew ▁spent ▁time ▁learning ▁pad ▁ 3 9 A ▁ev acu ation ▁procedures ▁and ▁test - dro ve ▁an ▁arm ored ▁tank ▁available ▁for ▁the ▁astr onaut s ▁to ▁escape ▁the ▁area . ▁They ▁also ▁board ed ▁Atl ant is ▁for ▁a ▁full ▁count down ▁simulation ▁on ▁ 2 3 ▁June . ▁ ▁La unch ▁attempts ▁ ▁Mission ▁tim eline ▁▁▁ 8 ▁July ▁( F light ▁Day ▁ 1 ▁– ▁La unch ) ▁▁ ▁The ▁launch ▁day ▁was ▁threatened ▁by ▁unf avor able ▁weather ▁leaving ▁only ▁a ▁ 3 0 % ▁chance ▁of ▁a ▁launch ▁occurr ing ; ▁this ▁changed ▁an ▁hour ▁before ▁launch ▁to ▁ 6 0 % ▁chance ▁of ▁launch . ▁Sat isf actory ▁weather ▁appeared ▁an ▁hour ▁before ▁the ▁launch ▁window ▁allowing ▁the ▁mission ▁to ▁proceed ▁as ▁planned . ▁La unch ▁director ▁Mike ▁Le in bach ▁conducted ▁the ▁final ▁series ▁of ▁GO / NO ▁GO ▁pol ls ▁to ▁verify ▁the ▁launch ▁read iness . ▁Sh utt le ▁La unch ▁Integr ation ▁Manager ▁Michael ▁P . ▁Mos es ▁also ▁issued ▁a ▁w ai ver ▁for ▁return ▁to