Discovery’s five astronauts said their successful mission removed the “ghost” of Challenger that had haunted the U.S. manned space program and opened the way for a new era of shuttle flights. Commander Frederick H. Hauck also announced plans to retire from the rolls of active astronauts, but the other members of the first U.S. crew to fly since the 1986 Challenger accident--co-pilot Richard O. Covey, George D. Nelson, David C. Hilmers and John M. Lounge--said they are eager to blast off into space again. “It’s nice to finish up a phase in one’s life on a high note,” Hauck, 47, said at a post-mission news conference at the Johnson Space Center in Houston. Hauck said he is looking at other opportunities in the space agency and the Navy, where he holds the rank of captain. The most anxious moments of the flight came during the liftoff Sept. 29 from Kennedy Space Center, Fla., Covey said. “It was a very, very long 8 1/2 minutes to (main engine cutoff),” he said.