NASA marks 20 years since space shuttle Columbia disaster

By MARCIA DUNN
AP Aerospace Writer

CAPE CANAVERAL, Fla. (AP) — NASA is marking the 20th anniversary of the space shuttle Columbia tragedy with somber ceremonies during its annual tribute to fallen astronauts. More than 100 people gathered under a gray sky at Florida’s Kennedy Space Center on Thursday to remember not only Columbia’s crew of seven, but the 18 other astronauts killed in the line of duty. NASA’s two shuttle accidents account for more than half of the names carved into the black granite of the Space Mirror Memorial. Columbia was destroyed during reentry in 2003 after a piece of fuel-tank foam came off and punctured the left wing during liftoff.