Jan. 16, 2003: Columbia Launch Date

10:39 a.m. EST -- Space shuttle Columbia, NASA's oldest shuttle, takes off with a crew of seven from Kennedy Space Center in Cape Canaveral, Fla., for a 16-day research mission.

Shortly after liftoff, a piece of insulating foam on the shuttle's external fuel tank comes off and is believed to have hit the left wing. Mission Control assures reporters that engineers have concluded that any damage to the wing is minor and poses no safety hazard.

Jan. 17, 2003: Day 1

Astronauts spend their first full day in space conducting experiments on subjects ranging from dust storms to prostate cancer.

Jan. 18, 2003: Day 2

Crew members collect their own blood, urine and saliva samples for experiments that look at how astronauts are affected by bone loss, kidney stones, muscle loss and weakened immune systems.

Jan. 19, 2003: Day 3

Astronauts set small fires inside their orbiting laboratory in a scientific study of soot, a pollutant that can lead to lung disease.

Jan. 20, 2003: Day 4

Astronaut Dave Brown photographs sprites, which are red flashes of electricity shooting up from thunderclouds 13 miles into the ionosphere, and elves, which are glowing red doughnut shapes radiating 190 miles.

Jan. 21, 2003: Day 5

Israel's first astronaut, Ilan Ramon, holds up a tiny Torah scroll, fulfilling a promise made by a Holocaust survivor 59 years ago.

Jan. 22, 2003: Day 6

Astronauts collect essential oils from blooming flowers in an experiment sponsored by the fragrance industry.

Jan. 23, 2003: Day 7

Hoping to create a new space scent, astronauts extract and preserve essential oils from blooming flowers in the fragrance industry experiment.

Jan. 24, 2003: Day 8

Crew members move some of their medical test equipment from the on-board laboratory into a cooler part of the ship after a dehumidifier breakdown causes the temperature to hit nearly 80 degrees.

Jan. 25, 2003: Day 9

Crew members try to further reduce the warm temperatures in their orbiting laboratory and begin taking sides for Sunday's Super Bowl.

Jan. 26, 2003: Day 10

Ilan Ramon sends "a very big shalom to Jerusalem." Ramon is photographing desert dust drifting over the Mediterranean in order to assess its impact on the weather.

Jan. 27, 2003: Day 11

Crew members take a break from scientific research for a chess game and to chat via radio about their families and their work.

Jan. 28, 2003: Day 12

11:39 a.m. EST -- Columbia's astronauts interrupt their round-the-clock research for a moment of silence to remember the seven Challenger astronauts who died on Jan. 28, 1986 and the three Apollo astronauts who were killed on Jan. 27, 1967.

Jan. 29, 2003: Day 13

Astronaut Ilan Ramon says he wishes his homeland -- in fact, all of the Middle East -- was as quiet and peaceful as it looks from space. Crewmate Laurel Clark says it's "magical" watching a rose bloom in orbit.

Jan. 30, 2003: Day 14

Ramon captures images of smoke from the burning rain forest.

Jan. 31, 2003: Day 15

Columbia's crew wraps up more than two weeks' worth of scientific research in orbit. Astronauts looked at ant, bee and spider behavior in weightlessness, and changes in flames and flower scents in orbit. They also measured atmospheric dust and collected blood and urine samples.

"It's kind of with mixed emotions that we get ready to come home," astronaut Michael Anderson tells Mission Control late Friday afternoon. "But we have enough fond memories to last us for a lifetime."

Feb. 1, 2003: Columbia Landing Date

8:15 a.m. EST -- Columbia fires braking rockets, streaks toward a planned touchdown at Kennedy Space Center, Runway 33.

8:53 a.m. -- NASA loses temperature measurements for the shuttle's left hydraulic system.

8:58 a.m. -- NASA loses measurements from three temperature sensors on the shuttle's left side.

8:59 a.m. -- Eight more temperature measures and pressure measures for left inboard and outboard tires are lost. Crew is able to acknowledge remaining visible measurement on display panel. In response to request for tire pressure status, Columbia replies: "Roger, uh, ...." This is the final transmission from the crew.

9 a.m. -- Mission Control suddenly loses all data and voice contact with Columbia 207,135 feet above north central Texas, traveling at 12,500 mph. Residents of Texas, Arkansas and Louisiana report hearing a "big bang" and seeing flames in the sky.

9 a.m. to 9:16 a.m. -- President Bush is informed of the possible disaster at Camp David.

9:16 a.m. -- Columbia's scheduled landing time at Kennedy Space Center.

9:29 a.m. -- NASA declares an emergency and sets up "contingency."

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

10:30 a.m. -- Bush speaks with NASA Administrator Sean O'Keefe. The president decides to travel back to the White House. 

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

12:30 p.m. -- Bush returns to the Oval Office. National Security Adviser Condoleezza Rice is already at the White House.

12:40 to 12:45 p.m. -- Bush offers the nation's condolences to the victims' families in a phone call.

Shortly before 1 p.m. -- Bush orders that all flags flying over federal buildings be lowered to half-staff.

1:25 p.m. -- Bush calls Israeli Prime Minister Ariel Sharon. Both men express their deepest condolences.

2:04 to 2:08 p.m. -- President Bush addresses a nation in mourning. "Columbia is lost; there are no survivors," he announces.

The Associated Press contributed to this report.