Rick Husband, 45, served as commander of the Columbia shuttle mission. A native of Amarillo, Texas, he was as an Air Force test pilot before being selected as an astronaut in 1994 on his fourth try. This was his second space flight. On his first trip to space in 1999, Husband was part of the first shuttle mission to the International Space Station.

Husband was married and had two children. He received a bachelor of science in mechanical engineering from Texas Tech University in 1980 and a master of science in mechanical engineering from California State University-Fresno in 1990.

Columbia pilot William McCool, 41, was a Navy commander from Lubbock, Texas. He served as a test pilot and squadron commander before becoming an astronaut in 1996. The Columbia mission was his first space flight.

McCool was married and had three children. He earned a bachelor of science in applied science from the U.S. Naval Academy, a master of science in computer science from the University of Maryland in 1985, and a master of science in aeronautical engineering from the U.S. Naval Postgraduate School in 1992.

One of only a handful of African American astronauts, payload commander Michael Anderson, 43, served as an Air Force instructor pilot and tactical officer before joining NASA in 1994. He traveled to Russia's Mir space station in 1998 on his first and only other space flight. He was in charge of Columbia's dozens of science experiments.

Anderson was married and lived in Spokane, Wash. He received a bachelor of science in physics/astronomy from University of Washington in 1981 and a master of science in physics from Creighton University in 1990.

Mission specialist Kalpana Chawla, 41, emigrated to the United States from India in the 1980s and became an astronaut in 1994. Chawla was the first Indian-born woman in space. She was born in Karnal, about 80 miles north of New Delhi.

Chawla made her first space flight in 1997 as mission specialist and prime robotic arm operator. The Columbia mission was her second space flight.

Chawla received a bachelor of science in aeronautical engineering from Punjab Engineering College, India, in 1982, a master of science in aerospace engineering from the University of Texas-Arlington in 1984, and a doctorate in aerospace engineering from the University of Colorado-Boulder in 1988. She is an FAA Certified Flight Instructor and has logged more than 376 hours in space.

Mission specialist David M. Brown, 46, was an Arlington, Va., native and went on to become a Navy captain, pilot and doctor before joining NASA in 1996. Columbia's mission was his first space flight.

Brown received a bachelor of science in biology from the College of William and Mary in 1978 and a doctorate in medicine from Eastern Virginia Medical School in 1982.

Mission specialist Laurel Blair Salton Clark, 41, a U.S. Navy commander, was onboard Columbia for her first space flight. Clark was a medical school graduate and trained in the Navy as an undersea medical officer and subsequently as a naval flight surgeon before joining NASA in 1996.

Clark was married with an 8-year-old son. Her home is in Racine, Wis.

Clark received a bachelor of science in zoology from the University of Wisconsin-Madison in 1983 and a doctorate in medicine from the same school in 1987.

Payload specialist Ilan Ramon, 48, a colonel in Israel's air force, was the first Israeli in space. He served as a fighter pilot beginning in the 1970s, and flew F-16s and F-4s. He was chosen as Israel's first astronaut in 1997, then moved to Houston the next year to train for shuttle flight. Ramon's mother and grandmother survived Auschwitz death camp. Father fought for Israel's statehood alongside grandfather. Ramon fought in Yom Kippur War 1973 and Lebanon War 1982.

He was married and had four children.

Ramon received a bachelor of science in electronics and computer engineering from the University of Tel Aviv, Israel, in 1987.