In Spare Parts, the most difficult task for the remotely operated vehicles (ROVs) is extracting a fluid sample from a barrel underwater. Lorenzo comes up with an elegantly simple solution to the problem, using a balloon inside a milk carton. When MIT faces this challenge during the competition, they are unable to complete it, finding that their sampling tube will not fit into the barrel. The team from Carl Hayden High School, however, finds that, although their sample is slightly diluted, they are able to complete the task successfully and win the competition.

Spare Parts is a classic story of the underdogs coming out on top. Even after this event, the Carl Hayden team is unable to believe that they have beaten MIT. They regard the simple materials and methods they have used as a point against them. However, MIT's attempt to solve the same problem was over-engineered and ultimately ineffective. The competition judge from NASA, Lisa Spence, praises the elegant parsimony of Lorenzo's design, saying that there is no point in coming up with a complicated solution when a simple one will get the job done. She says that she recognizes the thinking behind the team's approach as being similar to that of the scientists at NASA.