Windows on Spacecraft: The Balance of Safety and Psychological Comfort

Windows, which have provided astronauts with the outside world since the beginning of human space travel, are undergoing a significant transformation with the new generation of spacecraft.

NASA engineers plan to increase the use of acrylic materials in the future to reduce the risks caused by the brittle nature of glass.

According to experts, windows are not just a detail that offers a view. It also plays an important role in preserving the psychological comfort of astronauts in future space missions that may last months or even years.

In the first manned space missions, the area that astronauts could see outside was very limited. There were only small windows in the Mercury capsule of Alan Shepard, one of the first US astronauts, and in the vehicle of Yuri Gagarin, the first human in space.

This situation changed with the development of space vehicles. The seven-window Cupola module on the International Space Station has become one of the most important areas from which astronauts can monitor the Earth.

SpaceX also installed a large dome window in the Crew Dragon capsule for the Inspiration4 mission in 2021. Space tourism companies such as Virgin Galactic and Blue Origin have also made it one of the important features of their vehicles that passengers can see the Earth from as wide an angle as possible.

According to Samuel Coniglio IV, author of "Creature Comforts in Space," windows have a similar importance to basic comfort elements such as plants and showers for people who will live in space for long periods of time.

Coniglio states that humans cannot just live in a closed box, and says that being able to see space and the outside world helps astronauts connect with their environment.

The strong cognitive and emotional change caused by seeing the Earth from a distance during space travel is known as the "Overview Effect".

But large windows create a serious problem for engineers. Lynda Estes, an engineer who works on spacecraft windows at NASA Johnson Space Center, states that glass is inherently fragile and can lose its structural strength over time.

Microscopic defects on glass can grow over time. This process, called "static fatigue", can affect the durability of the window during long missions.

Another risk is that the glass breaks into sharp pieces when broken. According to Estes, creating a large opening in the body of a pressurized spacecraft and placing glass there carries a structural risk in itself.