What is a Spacewalk?

A spacewalk, also known as Extravehicular Activity (EVA), is when an astronaut leaves the safety of a spacecraft to work in the vacuum of space. Spacewalks are vital for spacecraft maintenance, scientific experiments, and construction tasks outside space stations.

How Spacewalks Work

Astronauts wear specially designed spacesuits called Extravehicular Mobility Units (EMUs). These suits provide:

  • Oxygen supply
  • Temperature regulation
  • Protection from micrometeoroids and radiation
  • Communication systems

Preparation Steps:

  1. Pre-breathing pure oxygen to avoid decompression sickness.
  2. Donning the spacesuit and safety harnesses.
  3. Depressurizing the airlock.
  4. Exiting the spacecraft.

Spacewalk Timeline

Year Event
1965 First spacewalk: Alexei Leonov (Voskhod 2, USSR)
1965 First American spacewalk: Ed White (Gemini 4)
1969 First Moonwalk: Neil Armstrong & Buzz Aldrin (Apollo 11)
1984 First untethered spacewalk: Bruce McCandless (MMU)
1998 First ISS assembly spacewalk
2013 First all-female spacewalk planned (delayed)
2019 First all-female spacewalk: Christina Koch & Jessica Meir
2022 First spacewalk using commercial Axiom Space suit

Diagram: Spacewalk Essentials

Spacewalk Diagram

Key Purposes of Spacewalks

  • Maintenance: Repairing satellites, replacing parts on the ISS.
  • Construction: Assembling modules and solar arrays.
  • Science: Deploying experiments, collecting samples.
  • Rescue: Emergency repairs or retrievals.

Surprising Facts

  1. Astronauts’ fingerprints can wear down: Handling tools during spacewalks causes suit gloves to abrade, sometimes wearing down astronauts’ fingerprints.
  2. Spacewalks can last over 8 hours: The longest EVA was 8 hours, 56 minutes (STS-102, 2001).
  3. Water leaks pose a real danger: In 2013, astronaut Luca Parmitano’s helmet filled with water, risking drowning in space.

Environmental Implications

Spacewalks and Space Debris

  • Spacewalks occasionally result in accidental loss of tools or materials, contributing to space debris.
  • Lost items (e.g., tool bags, gloves) remain in orbit and pose collision risks to spacecraft.

Plastic Pollution Connection

Recent studies have revealed plastic pollution in the deepest ocean trenches (Jamieson et al., 2020). Microplastics have been found in the Mariana Trench, highlighting how human activity reaches even the most remote environments. The connection to spacewalks is indirect but relevant:

  • Materials from spacewalks (plastics, metals) can eventually re-enter Earth’s atmosphere and, if not fully incinerated, contribute to surface and oceanic pollution.
  • The use of plastics in spacesuits and tools raises concerns about long-term environmental impacts as these materials degrade.

Atmospheric Re-entry

  • Discarded or lost items during EVAs may eventually burn up in Earth’s atmosphere, but some fragments survive and reach the surface or ocean.
  • These fragments, often plastic or composite, add to terrestrial and marine pollution.

Global Impact

Technological Advancement

  • Spacewalks enable international collaboration (e.g., ISS) and drive innovations in materials science, robotics, and safety protocols.

Environmental Awareness

  • The visibility of spacewalks raises public awareness about the fragility of Earth’s environment and the need for responsible exploration.
  • Incidents like tool loss during EVAs prompt discussions on debris mitigation and sustainable practices.

Policy and Regulation

  • Agencies like NASA and ESA have developed guidelines to minimize debris from EVAs.
  • International treaties, such as the Outer Space Treaty, emphasize the need to avoid harmful contamination of space and celestial bodies.

Recent Research

A 2020 study published in Nature Communications (Jamieson et al., 2020) found microplastics in the Mariana Trench, demonstrating the global reach of plastic pollution. This highlights the importance of considering the environmental footprint of all human activities, including space exploration.

Citation: Jamieson, A.J., et al. (2020). “Microplastics and anthropogenic fibres in the abyssal ocean.” Nature Communications, 11, 615.

Risks and Safety

  • Radiation Exposure: Spacewalks increase exposure to cosmic rays and solar radiation.
  • Temperature Extremes: Astronauts face temperatures from -157°C to 121°C.
  • Micrometeoroids: High-speed particles can puncture suits or equipment.
  • Life Support Failure: Oxygen, carbon dioxide removal, and cooling systems must function perfectly.

Spacewalk Innovations

  • Robotic Assistance: Use of robotic arms reduces the need for human EVAs.
  • Advanced Materials: Development of puncture-resistant, flexible suit fabrics.
  • Augmented Reality: Heads-up displays in helmets for navigation and instructions.

Conclusion

Spacewalks are essential for the advancement of space exploration and science. However, they carry risks for astronauts and the environment. The discovery of plastic pollution in the deepest ocean trenches serves as a reminder that human activities, even in space, can have far-reaching impacts. Responsible management, technological innovation, and international cooperation are critical for minimizing environmental consequences.

Additional Resources