These sensors detected problems over California. They went out over Texas at burn-through. Problems were detected at 8:53 I believe. Columbia was over California at 8:53.
A timeline of events in the last flight of space shuttle Columbia. All times EST.
-- Jan. 16, 10:39 a.m.: Columbia rockets into orbit from Kennedy Space Center.
-- Feb. 1, 8:15 a.m.: Columbia fires braking rockets, streaks toward touchdown.
-- 8:53 a.m.: NASA loses temperature measurements for shuttle's left hydraulic system.
-- 8:58 a.m.: NASA loses measurements from three temperature sensors on shuttle's left side.
-- 8:59 a.m.: NASA loses eight more temperature measures and pressure measures for left inboard and outboard tires. One of the measurements remains visible to crew on a display panel; which crew acknowledges.
-- 8:59 a.m.: Final transmission. Mission Control radios: "Columbia, Houston, we see your tire pressure messages and we did not copy your last." Columbia replies: "Roger, uh, ..."
-- 9 a.m.: NASA loses all data and contact with Columbia at 207,135 feet.
-- 9 a.m.: Residents of Texas, Arkansas and Louisiana report hearing "a big bang" and seeing flames in the sky.
-- 9:16 a.m.: Columbia's scheduled landing time.
-- 9:29 a.m.: NASA declares an emergency.
-- 9:44 a.m.: NASA warns residents to stay away from possibly hazardous debris.
-- 11 a.m.: Kennedy Space Center lowers flag to half-staff.
-- 2:05 p.m.: President Bush announces: "Columbia is lost; there are no survivors."