▁the ▁overall ▁risk ▁to ▁the ▁Sh utt le . ▁Executive - level ▁decision ▁to ▁proceed ▁was ▁required ▁if ▁cat ast roph ic ▁impact ▁was ▁lik el ier ▁than ▁ 1 ▁in ▁ 2 0 0 . ▁On ▁a ▁normal ▁( low - or bit ) ▁mission ▁to ▁the ▁I SS ▁the ▁risk ▁was ▁approximately ▁ 1 ▁in ▁ 3 0 0 , ▁but ▁the ▁Hub ble ▁teles cope ▁repair ▁mission ▁was ▁flow n ▁at ▁the ▁higher ▁orb ital ▁alt itude ▁of ▁ ▁where ▁the ▁risk ▁was ▁initially ▁calculated ▁at ▁a ▁ 1 - in - 1 8 5 ▁( due ▁in ▁part ▁to ▁the ▁ 2 0 0 9 ▁satellite ▁collision ). ▁A ▁re - analysis ▁with ▁better ▁de br is ▁numbers ▁reduced ▁the ▁estimated ▁risk ▁to ▁ 1 ▁in ▁ 2 2 1 , ▁and ▁the ▁mission ▁went ▁ahead . ▁ ▁Deb ris ▁inc idents ▁continued ▁on ▁later ▁Sh utt le ▁miss ions . ▁During ▁ST S - 1 1 5 ▁in ▁ 2 0 0 6 ▁a ▁fragment ▁of ▁circuit ▁board ▁b ored ▁a ▁small ▁hole ▁through ▁the ▁radi ator ▁pan els ▁in ▁Atl ant iss ▁cargo ▁bay . ▁On ▁ST S - 1 1 8 ▁in ▁ 2 0 0 7 ▁de br is ▁ble w ▁a ▁bullet - like ▁hole ▁through ▁Ende av ours ▁radi ator ▁panel . ▁ ▁Mir ▁ ▁Imp act ▁wear ▁was ▁notable ▁on ▁Mir , ▁the ▁Soviet ▁space ▁station , ▁since ▁it ▁remained ▁in ▁space ▁for ▁long ▁periods ▁with ▁its ▁original ▁solar ▁module ▁pan els