The idea for what is known as the “Scotty Rocket,” came to Scott J. Horowitz and several fellow astronauts during brainstorming sessions after space shuttle Columbia disintegrated over Texas in 2003. “The idea was ‘safe, simple and soon,’ ” Horowitz said. Build the new rocket “in line,” with the spacecraft on top so debris won’t hit it during launch. Use shuttle technology whenever possible because it’s already certified to carry humans. And build it with shuttle engineers — to get it done quickly. “Quite frankly, people weren’t very interested,” Horowitz said. Things have changed.