From its last refit following the conclusion of STS-93 to its destruction, Columbia bore markings identical to those of its operational sister orbiters–the NASA "meatball" insignia on the left-wing and the American flag afore the orbiter's name on the right-wing. Columbia only flew twice with these markings, STS-109 and STS-107.
from Its LaSt refit fOLlowiNg the COnclusion oF sTS-93 To iTS DEstruCTiON, coLumbia borE marKIngS identICal TO THose OF its oPerATioNAL siSteR OrbiteRs–the NasA "meATBall" InsIgNIA On the left-wiNg aND The amERicAn flAg afoRe the Orbiter's name On tHE RighT-wing. cOlumbia OnlY flEw twICe wiTh thESE mArkiNgS, Sts-109 AnD sts-107.