▁The ▁Li OH ▁can ister s ▁are ▁used ▁to ▁scr ub ▁carbon ▁dio x ide ▁from ▁the ▁cabin ▁air ▁inside ▁the ▁sh utt le . ▁When ▁Atl ant is ▁is ▁dock ed ▁to ▁the ▁space ▁station , ▁the ▁station ▁Car bon ▁D io x ide ▁Rem oval ▁Assembly ▁( CD RA ) ▁takes ▁care ▁of ▁both ▁the ▁station ' s ▁and ▁Atl ant iss ▁air ▁rev ital ization . ▁However , ▁when ▁Atl ant is ▁fle w ▁solo ▁after ▁und ock ing , ▁Li OH ▁can ister s ▁were ▁required . ▁Regarding ▁the ▁G PC - 4 ▁issue , ▁Ali bar u ho ▁said ▁that ▁it ▁was ▁a ▁very ▁inf re quent ▁failure , ▁happened ▁before ▁only ▁on ▁ST S - 9 ▁and ▁the ▁last ▁time ▁a ▁problem ▁occurred ▁on ▁G PC ▁ 4 ▁was ▁on ▁Atl ant iss ▁ST S - 7 1 ▁mission . ▁▁ 1 6 ▁July ▁( F light ▁Day ▁ 9 ▁– ▁C argo ▁trans fers ) ▁ ▁Fl ight ▁day ▁ 9 ▁was ▁the ▁bonus ▁day ▁added ▁by ▁the ▁Mission ▁Management ▁Team ▁earlier ▁on ▁the ▁week ▁as ▁a ▁result ▁of ▁Atl ant is ▁having ▁been ▁able ▁to ▁save ▁enough ▁cry ogen ic ▁o xygen ▁and ▁hydro gen ▁to ▁power ▁its ▁fuel ▁cells ▁an ▁extra ▁day . ▁Through out ▁the ▁day , ▁the ▁four ▁member ▁ST S - 1 3 5 ▁crew ▁spent ▁more ▁time ▁to ▁move ▁supplies ▁and ▁equipment ▁between ▁the ▁I SS ▁and ▁the ▁R aff a ello ▁M PL M . ▁ ▁Early ▁on ▁the