By Associated Press

Full coverage of the crash  TODAY'S GLOBE NASA e-mails show worry over wing  PROFILES The crew of shuttle Columbia  GRAPHICS Shuttle Columbia statistics Columbia's final approach Map of shuttle debris area How a shuttle returns to Earth Debris strikes Columbia Keeping heat outside shuttle Focus on shuttle tiles Trouble in the left wing The private sector in space Spinoffs from space  MORE COVERAGE Deadly accidents in space program Timeline of Columbia's last flight Glossary of space shuttle terms  REALVIDEO | NECN.com | Help with video | Latest in the investigation Sen. Kennedy reacts to tragedy The future of shuttle program Searching for debris in Texas Debris leads to hospitalization John Glenn on the tragedy Radar captures falling debris NASA lowers flag to half-staff Witnesses heard a 'big bang' Profiles of the Columbia crew NASA official: 'A tragic day' Video clips require RealPlayer and Windows 98 or higher.  PHOTO GALLERIES Memorials to the astronauts Images from the mission  ON THE WEB Space shuttle Columbia About the mission (Needs Flash) Space shuttle reference manual Shuttle facts, activities, and history How the space shuttle lands Virtual tour of shuttle Columbia. Background on the Columbia NASA www.nasa.gov Space Shuttle Encyclopedia (unofficial site) www.shuttle.org  THE CHALLENGER DISASTER From the Globe archives: Challenger explodes Profiles of crew members Final words of crew Profile of Christa McAuliffe

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.

9 a.m.
Mission Control loses all data and contact with Columbia crew.

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.

9:29 a.m.
NASA declares emergency.

9:44 a.m.
NASA warns residents to stay away from possibly hazardous debris.

11 a.m.
NASA lowers flag next to its countdown clock at Cape Canaveral, Fla., to half-staff.

2:05 p.m.
President Bush: "Columbia is lost; there are no survivors."