After placing a wreath, daughters and sons of Challenger astronauts look up at the names of their loved ones on the Astronaut Memorial during a Day of Remembrance Ceremony to honor the lives of the seven crew members of the Challenger space shuttle on the 30th anniversary of the 1986 tragedy, at the Kennedy Space Center Visitor Complex on Thursday. In addition to paying tribute to the Space Shuttle Challenger, they also honored all of those who have fallen since the beginning of the U.S. space program. (Tim Shortt/Florida Today via AP)