NASA Spacewalks: 7 Fascinating Things Astronauts Do Outside the ISS

Few activities in space are as remarkable as watching an astronaut leave the safety of a spacecraft and float hundreds of kilometres above Earth.

These missions, known as spacewalks or extravehicular activities (EVAs), allow astronauts and cosmonauts to work directly on the exterior of a spacecraft. They can install equipment, repair systems, connect cables, upgrade power systems and prepare the International Space Station for future operations.

In August 2021, NASA announced coverage for two upcoming spacewalks involving Russian cosmonauts outside the International Space Station. The missions were part of a much larger effort to outfit Russia’s newly arrived Nauka multipurpose laboratory module for scientific operations.

The two spacewalks were scheduled for September 3 and September 9, 2021, with cosmonauts Oleg Novitskiy and Pyotr Dubrov carrying out the work. Their tasks included routing and connecting power and Ethernet cables, installing handrails and continuing the preparation of Nauka.

But these missions also provide a fascinating look at what happens whenever humans step outside the International Space Station.

What Are NASA Spacewalks?

NASA spacewalks are activities in which astronauts leave the protected interior of a spacecraft to work in the vacuum of space.

NASA uses the term extravehicular activity, or EVA, to describe this kind of work. Spacewalks can take place outside the International Space Station or, in the future, during missions around the Moon and other destinations. NASA describes spacewalking as an important capability for maintaining the station and enabling future exploration.

A spacewalk is very different from simply stepping outside a building.

There is no breathable atmosphere.

There is no normal air pressure.

There is no convenient floor to stand on.

Astronauts therefore rely on specially designed spacesuits and life-support systems throughout the activity.

Why Do Astronauts Need to Perform Spacewalks?

The International Space Station is an enormous laboratory made up of many modules, solar arrays, radiators, antennas and other systems.

Not everything can be repaired or installed from inside the station.

Some equipment is located on the exterior.

That is where spacewalks become necessary.

NASA explains that astronauts conduct spacewalks to perform maintenance, install new equipment and deploy science experiments.

A spacewalk can therefore be compared to sending a highly trained technician outside a building—but with one enormous difference:

The technician is working in space.

1. Spacewalks Help Build the Space Station

One of the most important roles of NASA spacewalks has been the construction and expansion of the International Space Station.

The ISS was not launched as one enormous structure.

Instead, different modules and components were delivered over many missions and gradually assembled in orbit.

Astronauts needed to connect equipment, install cables, attach structures and prepare systems for operation.

Spacewalks made much of this possible.

Even after the major construction phase, astronauts continue to perform exterior maintenance because the station is a working spacecraft exposed to the harsh environment of space.

2. Astronauts Can Install New Equipment

Spacewalks are not only about repairs.

Astronauts can also install equipment that improves the station.

Solar arrays are a good example.

The International Space Station requires a reliable supply of electrical power to operate its computers, laboratories, life-support equipment and other systems.

Astronauts have conducted spacewalks to install and upgrade the station’s solar-power systems.

In 2021, NASA astronauts also conducted spacewalks to install new roll-out solar arrays, demonstrating how EVAs can directly improve the station’s power-generation capability.

The same principle applied to the Russian Nauka module.

3. The Nauka Module Required Extensive Preparation

The 2021 spacewalks were particularly significant because they were connected to the arrival of Nauka.

Nauka, meaning “science” in Russian, is a multipurpose laboratory module that became part of the Russian segment of the International Space Station.

After its arrival, cosmonauts needed to carry out extensive work to prepare it for regular operations.

The first two spacewalks in this series involved Oleg Novitskiy and Pyotr Dubrov.

According to NASA’s reporting, the cosmonauts were preparing to route and connect power and Ethernet cables between Nauka and other station systems. They were also scheduled to install handrails and continue cable work during the second spacewalk.

The work was part of a much larger series of activities required to fully outfit the module.

Later records show that the September 2021 spacewalks successfully continued the work, including Ethernet connections, handrail installation and connections between Nauka and the Zvezda service module.

4. Spacewalks Can Repair Critical Systems

The ISS is constantly exposed to the extreme environment of space.

Its exterior systems experience radiation, extreme temperature changes and the effects of micrometeoroids and orbital debris.

Equipment can also simply fail.

When something goes wrong outside the station, astronauts may need to physically reach the equipment and repair or replace it.

One example came in December 2021, when NASA astronauts Tom Marshburn and Kayla Barron replaced a failed S-band antenna system outside the station.

Without the ability to perform exterior repairs, some failures could become much more difficult to address.

Spacewalks therefore provide the station with a valuable maintenance capability.

5. Astronauts Must Wear a Miniature Spacecraft

One of the most impressive aspects of a spacewalk is the spacesuit.

A space suit is not simply clothing.

NASA describes the Extravehicular Mobility Unit, or EMU, as effectively a miniature spacecraft that protects astronauts from the extreme environment outside the station.

The suit provides essential functions including:

• Oxygen
• Carbon dioxide removal
• Pressure
• Temperature control
• Communication
• Protection from the space environment

Without these systems, an astronaut could not survive in the vacuum of space.

The suit also allows astronauts to move their arms and hands while carrying out complicated tasks.

That is especially important because many spacewalk jobs require precise movements.

6. Spacewalks Require Extensive Training

Astronauts do not simply learn how to perform a task and then immediately go outside.

Spacewalks require extensive preparation.

One of the most important training facilities used by NASA is the Neutral Buoyancy Laboratory at Johnson Space Center.

Astronauts practice underwater because the environment can simulate some aspects of weightlessness.

NASA uses the facility to help crews train for space station spacewalks and other operations.

Astronauts also train with the tools and equipment they will use during the actual mission.

They practise procedures repeatedly so that they understand what to do before leaving the spacecraft.

This preparation is essential because mistakes outside the station can be extremely dangerous.

7. Spacewalks Are Carefully Planned

A spacewalk may look spontaneous when viewed on television.

In reality, almost every movement is carefully planned.

Mission controllers and astronauts prepare detailed procedures covering the work that needs to be completed.

They must consider:

• Spacesuit oxygen supply
• Carbon dioxide levels
• Battery power
• Communication
• Tools
• Astronaut positioning
• Safety procedures
• Airlock operations
• Station systems
• Emergency responses

A spacewalk can last for several hours.

That means astronauts need to manage their resources carefully.

They cannot simply return inside whenever they become tired.

Why Spacewalks Are So Dangerous

Space is an extremely hostile environment.

The International Space Station orbits Earth at roughly 400 kilometres above the surface, depending on its orbital position and changes over time.

Outside the station, an astronaut is exposed to vacuum, intense temperature variations, radiation and the danger of debris.

A spacesuit provides essential protection, but it does not eliminate every risk.

Astronauts must remain connected to the station or use appropriate safety systems to prevent drifting away.

They also need to monitor their suits continuously.

A small problem can become serious very quickly.

This is why NASA and its international partners devote so much time to training and preparation.

What Happens If Something Goes Wrong?

Space agencies plan extensively for emergencies.

Astronauts have procedures for different types of problems, including equipment malfunctions and spacesuit issues.

The space station also provides multiple layers of protection.

The airlock acts as the gateway between the pressurized interior and the vacuum of space.

Before an astronaut exits, the airlock must be prepared for the transition.

After the work is complete, the astronaut returns inside and the airlock is repressurized.

This process requires careful coordination between the astronauts and mission control.

The International Nature of Spacewalks

One of the remarkable aspects of the International Space Station is its international character.

The station has involved space agencies and astronauts from multiple countries, including the United States, Russia, Japan, Canada and European nations.

The 2021 Nauka spacewalks illustrate this international environment.

While Novitskiy and Dubrov were Russian cosmonauts working on the Russian segment, the work took place aboard the International Space Station, a multinational scientific facility.

NASA has noted that the ISS has served as a platform for research involving many countries and has provided a foundation for future exploration beyond low Earth orbit.

Spacewalks therefore represent not only technological achievement but also international cooperation.

Spacewalks Prepare Humanity for Future Missions

The importance of NASA spacewalks extends beyond the International Space Station.

The skills developed during orbital EVAs will be valuable as humans prepare for future missions to the Moon and eventually Mars.

Future explorers may need to construct habitats, repair equipment, maintain power systems and conduct scientific experiments outside spacecraft.

NASA’s current Extravehicular Activity and Human Surface Mobility Program is developing spacesuits, tools and other systems designed for both low-Earth-orbit operations and future lunar exploration.

The lessons learned on the ISS can therefore influence the next generation of human space exploration.

The station is effectively a test bed.

Astronauts learn how humans work outside spacecraft, how tools perform in microgravity and how equipment behaves after long exposure to space.

Those lessons can become valuable when missions move farther from Earth.

How Long Can a Spacewalk Last?

The length of a spacewalk depends on the mission and the work required.

Many ISS spacewalks last several hours.

For example, the second Nauka-related spacewalk in September 2021 lasted approximately 7 hours and 25 minutes. During that mission, Novitskiy and Dubrov continued cable connections and installed handrails and other equipment.

That is more than seven hours spent working outside a spacecraft in a pressurized suit.

It demonstrates just how physically and mentally demanding an EVA can be.

Why NASA Continues to Broadcast Spacewalks

Spacewalks are among the most visually impressive activities in human spaceflight.

They allow people on Earth to see astronauts working against the enormous backdrop of the planet.

NASA broadcasts and provides coverage of major spacewalks because they offer the public an opportunity to follow human space exploration in real time.

The broadcasts also help explain what astronauts are doing and why the work matters.

For students especially, seeing an astronaut repair equipment hundreds of kilometres above Earth can turn an abstract science lesson into something tangible.

The Future of Spacewalks

Spacewalks will remain an important part of human spaceflight.

The International Space Station still requires maintenance, upgrades and scientific work.

At the same time, NASA and other space agencies are preparing technologies for missions beyond low Earth orbit.

Future spacesuits will need to support astronauts in environments very different from the ISS.

Lunar explorers will face reduced gravity, abrasive lunar dust and extreme temperature conditions.

Mars missions will introduce even greater challenges.

That means today’s spacewalk technology is only part of a much longer journey.

The systems developed for the ISS can provide valuable experience, but future explorers will need new tools and capabilities.

Conclusion

NASA spacewalks represent one of the most demanding forms of human work in space.

Astronauts and cosmonauts leave the protection of their spacecraft and enter an environment where a spacesuit becomes their life-support system.

They repair equipment, install new technology, connect cables, upgrade power systems and prepare spacecraft for future missions.

The two spacewalks announced in 2021 were part of the effort to outfit Russia’s newly arrived Nauka laboratory module. Oleg Novitskiy and Pyotr Dubrov carried out the work, helping connect the module to the station’s systems and prepare it for scientific operations.

But the significance of these missions goes beyond Nauka.

Every successful spacewalk adds to humanity’s understanding of how people can live and work beyond Earth.

As NASA prepares for future lunar missions and eventually deeper exploration, that experience will become increasingly valuable.

A spacewalk may last only a few hours.

But the knowledge gained can help shape humanity’s future in space for decades to come.