Episode 14: Yo-Yos in Space

Astronaut and chemist Dr. Don Pettit does physics demos that are out of this world. Currently on board the International Space Station, Dr. Pettit presents fantastic physics that can only be demonstrated in micro-gravity.

Episode 14: Yo-Yos in Space

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Challenge Question: How is Don's "tether assist" like the tether technology used in satellites?

Challenge Answer: Don's yo-yo acts like an end-mass in a momentum exchange tether system. He spins thestring(tether), thus exerting a centripetal force on the yo-yo. Given that a 2-bodysystem will orbit around its center of mass and Don's hand represents a satellite, the yo-yo and his hand will experience constant acceleration. Momentum exchange can occurif an end-mass is released during rotation. A transfer in momentum to the released masscauses the system to change orbital energy, adjusting satellite orbit.

Challenge Winner: Indronil Ghosh of Folsom, CA