Extravehicular activity (EVA) represents one of the most demanding operations in human spaceflight.

When astronauts leave a space station to work outside in orbit, they step into an environment that requires extreme precision, careful planning, and complete coordination.

EVA is essential for maintaining onboard systems, installing new equipment, and supporting a wide range of scientific tasks conducted in space.

Although EVA may appear smooth and effortless when observed from Earth, the preparation behind it is highly structured and carefully controlled. Every stage is designed to ensure astronauts can adapt safely to the challenging conditions beyond the station. Nothing is left to chance, because even small variations in pressure, breathing balance, or physical readiness can influence performance during the mission.

<h3>Oxygen adaptation phase</h3>

One of the earliest and most important steps is oxygen adaptation. In this phase, we gradually increase the oxygen concentration that astronauts breathe inside a controlled environment.

The purpose is to reduce the amount of nitrogen dissolved in the body. Inside the space station, conditions are stable and comfortable, but the space suit environment is very different and requires a different breathing balance. By slowly increasing oxygen intake, the body adjusts in a controlled and safe way.

This process is not immediate. It is carefully monitored over time, allowing physiological systems to respond step by step. The goal is to prepare the body so it can function normally under lower-pressure conditions later during the spacewalk.

<h3>Controlled pressure adjustment</h3>

After oxygen adaptation, the next stage is controlled pressure adjustment. Here, the internal cabin pressure is gradually reduced to better match the environment inside the space suit.

This step is essential because sudden changes in pressure could affect comfort and stability. To avoid this, the adjustment is performed slowly, with continuous monitoring from onboard systems and ground support teams. Astronauts remain in a stable environment throughout the process while their bodies gradually adapt.

This careful transition ensures that when they enter the suit, the difference between inside and outside conditions is minimal and manageable.

<h3>Space suit preparation and system verification</h3>

Next comes one of the most technical stages: space suit preparation. Each suit is a self-contained life-support system designed to function independently outside the station.

We carry out detailed inspections of all major components, including oxygen supply systems, temperature regulation units, communication equipment, and mobility joints. Every part must be fully operational because the suit is the astronaut’s only protection in space.

Astronauts also perform internal movement checks while wearing the suit. They test arm flexibility, hand control, and visibility through the helmet visor. Even small details such as glove sealing, joint resistance, and internal cooling comfort are carefully verified. These checks ensure that astronauts can work efficiently without restriction once they are outside.

<h3>Final coordination and mission review</h3>

Before the spacewalk begins, final coordination checks are completed. Mission objectives are reviewed step by step with support teams on the ground. Tools required for the mission are organized, labeled, and secured to prevent any issues during movement outside. Communication systems are tested again to ensure stable contact throughout the EVA.

Timing is also carefully planned. Every action, from hatch opening to task completion, follows a precise schedule. This coordination helps maintain safety and ensures that astronauts can focus fully on their assigned tasks.

<h3>Spacewalk execution and safe return</h3>

When all preparations are complete, astronauts slowly exit the station and enter open space. Movements are controlled and deliberate, as working in microgravity requires careful coordination.

A spacewalk can last several hours depending on mission complexity. During this time, astronauts perform installation work, inspections, or repairs while maintaining constant communication with ground control.

After completing their tasks, they return to the station. The cabin environment is gradually restored to normal conditions so the body can readjust smoothly. Equipment is checked and stored properly, and monitoring continues for a period to ensure stability after the EVA.

<h3>Precision behind every step</h3>

The entire preparation process shows how much precision and teamwork are required for space exploration. From oxygen adaptation to suit testing and final coordination, every stage plays an essential role in ensuring astronaut safety and mission success.

Spacewalks represent some of the most complex operations in human spaceflight, and each one depends on careful planning long before the hatch is opened.

Lykkers, after learning this process, which step do you think is the most critical in preparing for work outside the station?