7 HOLES in the Space Station - Smarter Every Day 135

Destin introduces astronaut Don Pettit, who is renowned for capturing space photography from the International Space Station, including city tracking at night, aurora sequences, and time-lapse footage of Earth.

The cupola is located on Node 3 of the International Space Station and is the source of many famous photographs taken from space.

• Night time aurora and time lapse sequences of Earth • City tracking at night photography • Most iconic space photography from the station

Destin met with Don Pettit in person to discuss the engineering behind the cupola windows and their protective mechanisms.

• Protects windows from micro meteorites when closed • Provides thermal insulation from radiation environment of space • Operated manually from inside the station

The challenge is operating a lid on the outside of the space station by manipulating mechanical components on the inside while maintaining pressure seal and preventing air loss.

O-ring type seals are used throughout the hatch system, with a rotating shaft and multiple O-rings that maintain the pressure seal while allowing the shutter to open and close.

There are seven shutters on the cupola (one for each window). If a leak occurs, the entire cupola can be sealed off, and a spacewalk may be required to replace the mechanism.

Charlie VanValkenburgh is an industrial engineer from Auburn University with over a dozen patents who served as the lead engineer for the cupola shutter design 20 years ago.

After completing the Space Station Freedom project (which later became the International Space Station), Charlie left the space program and started his own business called Pit Bull Products.

Pit Bull Products manufactures a special motorcycle stand that uses leverage principles to lift motorcycles for maintenance work.

• Drawing package was handed to Italian space agency for fabrication • Charlie retained his own complete drawing package for reference • Design has operated flawlessly for 20 years on the space station

The inner shaft grooves are held to within 2000ths of an inch tolerance, controlling the interface between the groove and the outer wall that compresses the O-ring.

Two dynamic O-rings are in constant rotation with a shaft running through and rubbing against them, sealing breathable air inside from the vacuum of space.

The astronauts' breathable air is held back from the vacuum of space by two small O-rings, making this one of the most critical components in the cupola design.

The shutter design created 20 years ago continues to operate flawlessly today without any leaks or failures, demonstrating exceptional engineering quality.

European astronaut Samantha Cristoforetti provides a live demonstration of how to open and close the cupola shutters from the International Space Station.

• Each window has a handle that turns to open or close the shutter • Turning closes the window, turning the opposite direction opens it • Requires careful handling near the closed position to avoid hitting the structure hard

The shaft extends through the station structure to the outer space side. It feels cold to the touch but is regular metal cold, not extreme space cold. Direct mechanical connection with no bumper at the end.

Samantha Cristoforetti performs the Smarter Every Day outro from orbit, demonstrating the direct connection between the educational content and active astronauts on the station.

Destin was contacted by an astronaut on orbit who favorited his tweet, inspiring him to pursue this cupola engineering story and connect directly with Samantha Cristoforetti.

Astronauts regularly take photographs from the cupola and share them on social media, with many incredible images available for followers to see.

Follow astronauts on social media to see daily space photography and stay connected with the International Space Station activities.

Destin encourages viewers to subscribe if they find the content valuable, using O-rings as a playful reference to the central engineering topic of the episode.