A group of engineers was honored Tuesday for concocting a plan using plastic bags, cardboard and duct tape to save Apollo 13s astronauts after their spacecraft was crippled by an explosion 35 years ago. Astronauts Jim Lovell, Fred Haise and Jack Swigert would have died without the engineers quick thinking, said John Schneiter, president of GlobalSpec, the New York company that presented the award — a crystal globe. Sunday marked the 35th anniversary of the spacecraft's return to Earth after their aborted moon mission. It was crippled by an oxygen tank that overheated and exploded. During the spacecraft's voyage home, NASA began to fear that the carbon dioxide the astronauts expelled from their lungs as they breathed would eventually kill them. Engineers advising them from the ground figured out a way to retrofit their equipment to scrub the air of carbon dioxide. "It was clearly a show stopper in this flight," Haise said Tuesday. "I'm very appreciative and thankful because otherwise, I wouldn't be here with you today." Engineers who solved the problem, astronauts from the Apollo program and others gathered for Tuesday's ceremony at Space Center Houston, an educational complex next to the Johnson Space Center. The awards presentation took place in a theater that includes the podium from which President Kennedy urged the nation in 1962 to send men to the Moon.