MythBusters Episode 244: Rocketman

A rocket can be fueled with gummy bears.

plausible

Adam introduced a hybrid rocket 7 feet (2.1 m) in length and 4 inches (10 cm) in diameter. He explained that it functioned by spraying liquid oxygen through a cylinder containing the propellant (the “fuel grain”), allowing for highly energetic combustion. Adam and Jamie made three different types of fuel grains: one with hand-packed gummy bears, one with melted-down gummy bears, and one with boiled gummy bears. Boiling the gummy bears at 305 °F (152 °C) removed any water and created a hard candy when cooled.

With the help of a rocketry club, Adam and Jamie attempted to launch their rockets at a testing range. Despite ignition and some flames, none of the three engines resulted in a liftoff. At this point Adam and Jamie suspected that there was a problem with the other components of their rocket. They conducted a control test using standard paraffin-based rocket fuel and their suspicions were confirmed by a very lackluster launch. They concluded that their hybrid rocket design was too finicky and they returned to the shop to devise a new plan.

The hybrid rocket was abandoned in favor a simpler solid rocket. Adam boiled the gummy bears in a microwave and ground the residue into a fine powder. The powder was sent off to a licensed specialist to be incorporated into a solid rocket engine. Back at the range, a control launch with standard fuel achieved an altitude of 4,491 feet (1,369 m). The launch with the gummy bear engine was successful and achieved an altitude of 3,691 feet (1,125 m). They classified the fuel as plausible, with Adam noting that the reduced efficiency makes the gummy bears effectively useless as an actual rocket fuel.

A rocket can be fueled with poop.

plausible

Jamie considered the possibility that astronauts might be able to recycle their bodily waste for practical purposes. He dried a batch of dog feces in the sun on the shop roof and reduced it to a powder in a tumbler. Like the gummy bear powder, this powder was sent off to a specialist to be incorporated into a solid rocket engine. The ensuing launch reached an altitude of 2,900 feet (880 m). Adam and Jamie judged the feces as a plausible fuel, noting that it is an abundant resource.