Sean Riley puts on his radiation suit and heads into the radiation zone for his next tough fix, replacing a steam turbine in a nuclear power plant to boost its energy-producing capacity.

Sean Riley joins a team of engineers and mechanics as they attempt to fix a damaged Boeing 767 jet. This is a crucial fix-taking a jet apart and putting it back together is a complex, three-week operation, and the smallest mistake could have huge consequences. As the new guy on the project, Riley is given an unpleasant task to prove his mettle-disconnecting a lavatory tube.

Sean Riley joins an elite corps of engineers who dangle from a helicopter and work with live power lines carrying a shocking 500,000 volts of electricity.

Sean Riley helps swap out a 38-ton engine on one of the largest ships in the Gulf of Mexico. The fix must be done in the middle of the gulf-and with swells, wind and rain, things can get complicated.

For this tough job, Sean Riley joins a team of engineers to move and clean a 27-foot, 23-ton, $15 million telescope mirror. Here, three telescopes are used together to form the largest combined telescope in the world.

Sean Riley works to fix a faulty TV antenna nearly half a mile in the air. This extreme fix takes strength, teamwork and guts.