br is ▁from ▁the ▁der el ict ▁satellite ▁Kos mos ▁ 9 5 5 . ▁Similar ▁man eu vers ▁were ▁initi ated ▁on ▁miss ions ▁ 5 3 , ▁ 7 2 ▁and ▁ 8 2 . ▁ ▁One ▁of ▁the ▁earliest ▁events ▁to ▁public ize ▁the ▁de br is ▁problem ▁occurred ▁on ▁' s ▁second ▁flight , ▁ST S - 7 . ▁A ▁fle ck ▁of ▁paint ▁struck ▁its ▁front ▁window , ▁creating ▁a ▁pit ▁over ▁ ▁wide . ▁On ▁ST S - 5 9 ▁in ▁ 1 9 9 4 , ▁Ende av our ' s ▁front ▁window ▁was ▁p itted ▁about ▁half ▁its ▁depth . ▁Minor ▁de br is ▁impact s ▁increased ▁from ▁ 1 9 9 8 . ▁ ▁Window ▁ch ipping ▁and ▁minor ▁damage ▁to ▁thermal ▁protection ▁system ▁t iles ▁( TP S ) ▁were ▁already ▁common ▁by ▁the ▁ 1 9 9 0 s . ▁The ▁Sh utt le ▁was ▁later ▁flow n ▁tail - first ▁to ▁take ▁a ▁greater ▁proportion ▁of ▁the ▁de br is ▁load ▁on ▁the ▁engines ▁and ▁rear ▁cargo ▁bay , ▁which ▁are ▁not ▁used ▁in ▁orbit ▁or ▁during ▁descent , ▁and ▁thus ▁are ▁less ▁critical ▁for ▁post - launch ▁operation . ▁When ▁flying ▁attached ▁to ▁the ▁I SS , ▁the ▁two ▁connected ▁space craft ▁were ▁f li pped ▁around ▁so ▁the ▁better - arm ored ▁station ▁shield ed ▁the ▁orb iter . ▁ ▁A ▁NASA ▁ 2 0 0 9 ▁study ▁concluded ▁that ▁de br is ▁account ed ▁for ▁approximately ▁half ▁of