1. Definition

A spacewalk (Extravehicular Activity, EVA) is any activity astronauts perform outside their spacecraft in space. Spacewalks are essential for spacecraft maintenance, scientific experiments, and construction of structures like the International Space Station (ISS).

2. History

  • First spacewalk: Alexei Leonov (Soviet Union), 1965.
  • First American spacewalk: Ed White, 1965.
  • Longest single spacewalk: 8 hours, 56 minutes (Susan Helms & Jim Voss, 2001).

3. Purpose of Spacewalks

  • Maintenance: Repairing or upgrading spacecraft, satellites, or space stations.
  • Assembly: Building structures such as ISS modules.
  • Science: Collecting samples, testing new technologies.
  • Emergency: Responding to unexpected issues (e.g., damage from micrometeoroids).

4. Spacewalk Equipment

  • Spacesuit (Extravehicular Mobility Unit, EMU): Provides oxygen, temperature control, and protection from micrometeoroids.
  • Safety Tethers: Prevent astronauts from drifting away.
  • Tools: Specially designed for use with gloves and in microgravity.
  • Communication Systems: Built into the helmet for contact with mission control.

5. Preparation and Training

  • Neutral Buoyancy Lab: Astronauts train underwater to simulate microgravity.
  • Virtual Reality: Used for practicing complex maneuvers.
  • Physical Conditioning: Spacewalks are physically demanding.

6. Spacewalk Procedure

  1. Pre-EVA Checklist: Equipment check, suit integrity, oxygen levels.
  2. Depressurization: Airlock is depressurized to vacuum.
  3. Egress: Astronauts exit the spacecraft.
  4. Task Execution: Perform assigned tasks (repairs, experiments).
  5. Ingress: Return to airlock.
  6. Repressurization: Airlock is re-pressurized.

7. Dangers and Risks

  • Radiation Exposure: No atmospheric shielding.
  • Temperature Extremes: -157°C to +121°C in sunlight/shadow.
  • Micrometeoroids: Can puncture suits.
  • Suit Malfunctions: Oxygen leaks, cooling failures.
  • Disorientation: Microgravity can cause spatial confusion.

8. Diagram: Astronaut on Spacewalk

Spacewalk Diagram

9. Surprising Facts

  1. Astronauts’ fingernails can fall off due to pressure and friction inside gloves during spacewalks.
  2. Spacewalk suits weigh over 125 kg on Earth, but in microgravity, they feel weightless.
  3. Astronauts can see flashes of light (cosmic rays) inside their eyes during spacewalks.

10. Controversies

  • Safety vs. Mission Needs: Some argue spacewalks are too risky for routine maintenance; robotic alternatives are debated.
  • Cost: Training, equipment, and support for spacewalks are expensive.
  • Gender Suitability: NASA faced criticism in 2019 for lack of properly sized suits for female astronauts, leading to canceled EVAs.

11. Debunking a Myth

Myth: “If an astronaut’s suit gets punctured, they explode instantly.”

Fact: A suit puncture would cause gradual depressurization, not instant explosion. The astronaut would have time to return to the airlock if the breach is small.

12. Future Trends

  • Robotic Assistance: Increasing use of robotic arms and drones for routine tasks.
  • Advanced Suits: Development of lighter, more flexible suits with improved life support.
  • Commercial Spacewalks: Private companies (e.g., SpaceX, Axiom Space) plan spacewalks for tourists and commercial missions.
  • Lunar and Mars EVAs: Suits and procedures are being designed for surface exploration on the Moon and Mars.

13. Recent Research

A 2022 study published in npj Microgravity (Fong et al., 2022) analyzed physiological stresses during spacewalks, finding that cardiovascular strain is higher than previously estimated, prompting redesigns in suit cooling and monitoring systems.

Reference:
Fong, K., et al. (2022). “Cardiovascular responses during extravehicular activity simulation.” npj Microgravity. Link

14. Quantum Computers and Spacewalks

Quantum computers use qubits, which can be both 0 and 1 at the same time (superposition). Although not directly related, quantum computing may eventually help optimize spacewalk planning and suit design by simulating complex scenarios beyond classical computing capabilities.

15. Summary Table

Aspect Details
First Spacewalk 1965, Alexei Leonov
Suit Weight 125 kg (Earth), weightless in space
Risks Radiation, temperature, micrometeoroids
Training Underwater, VR, physical conditioning
Future Trends Robotics, advanced suits, commercial EVAs

16. Conclusion

Spacewalks are critical for space exploration, but they carry significant risks and costs. Ongoing research and technological innovation are making EVAs safer and more efficient, with future missions set to expand human activity beyond Earth orbit.