FILE - In this Jan. 28, 1986 file photo, the space shuttle Challenger explodes shortly after lifting off from the Kennedy Space Center in Cape Canaveral, Fla. Sony Electronics and the Nielsen television research company collaborated on a survey ranking TV's most memorable moments. Other TV events include, the Sept. 11 attacks in 2001, Hurricane Katrina in 2005, the O.J. Simpson murder trial verdict in 1995 and the death of Osama bin Laden in 2011. (AP Photo/Bruce Weaver, File)