Revision Sheet

Definition

Spacewalks, or Extravehicular Activities (EVA), involve astronauts exiting their spacecraft to work in the vacuum of space. Tasks include maintenance, repairs, scientific experiments, and construction outside space stations or vehicles.

Timeline of Key Spacewalks

Year Event
1965 First spacewalk: Alexei Leonov (Voskhod 2, USSR)
1969 Moonwalk: Neil Armstrong & Buzz Aldrin (Apollo 11, USA)
1973 First US spacewalk: Ed White (Gemini 4)
1984 First untethered spacewalk: Bruce McCandless (MMU, STS-41B)
1998 First ISS assembly spacewalk
2013 First all-female spacewalk planned (postponed to 2019)
2019 First all-female spacewalk: Christina Koch & Jessica Meir
2022 ESA’s Samantha Cristoforetti: first European woman to perform an EVA outside ISS

Spacewalk Equipment

  • Spacesuit (Extravehicular Mobility Unit - EMU):
    Provides oxygen, temperature regulation, radiation protection, and mobility.
  • Safety Tethers:
    Prevent astronauts from drifting away.
  • Tool Bags:
    Specialized tools for repairs/construction.
  • Helmet Cameras:
    Real-time video for mission control.
  • Communications Systems:
    Continuous contact with ground and crew.

Spacewalk Diagram

Procedure

  1. Preparation:
    Suiting up, pre-breathing pure oxygen to prevent decompression sickness.
  2. Airlock Egress:
    Exiting through a pressurized airlock.
  3. Task Execution:
    Repairs, installations, experiments.
  4. Return:
    Re-entering the airlock, repressurizing, and suit removal.

Risks & Challenges

  • Vacuum Exposure:
    No air; suit failure can be fatal.
  • Temperature Extremes:
    Ranges from -157°C (shade) to +121°C (sunlight).
  • Radiation:
    Increased cosmic and solar radiation.
  • Physical Strain:
    Suits are heavy and rigid; tasks require strength and dexterity.
  • Space Debris:
    Micrometeoroids and orbital debris pose collision risks.

Recent Breakthroughs

  • Robotic Assistance:
    Robotic arms (e.g., Canadarm2) now support astronauts, reducing manual workload.
  • Smart Spacesuits:
    NASA’s xEMU (2022) offers improved mobility, modularity, and life support.
  • Augmented Reality (AR):
    AR overlays in helmet visors guide complex repairs (NASA, 2021).
  • Long-duration EVAs:
    Astronauts now perform spacewalks lasting over 7 hours, improving construction efficiency.
  • International Collaboration:
    ESA, NASA, Roscosmos, and JAXA jointly train and execute EVAs.

Recent Study:
A 2022 NASA-JSC report (“Extravehicular Activity Technology Development for Artemis Missions”) details advancements in suit design and EVA planning for lunar and Mars missions.
Source

Surprising Facts

  1. Astronauts can lose up to 2 liters of sweat during a single spacewalk due to suit insulation and physical exertion.
  2. Spacewalk suits contain up to 16 layers of specialized material, including Kevlar and Mylar, to protect against micrometeoroids and extreme temperatures.
  3. The longest spacewalk lasted 8 hours and 56 minutes (2001, STS-102, ISS assembly).

Connection to Technology

  • Materials Science:
    Advanced polymers and composites enable durable, flexible suits.
  • Miniaturized Life Support Systems:
    Portable oxygen, CO₂ scrubbers, and cooling systems.
  • Telecommunications:
    Real-time video and telemetry for remote guidance.
  • Robotics:
    Integration with robotic arms and drones for remote tasks.
  • Wearable Computing:
    Heads-up displays, biometric monitoring, and AR interfaces.

Spacewalks & Earth Observation

Spacewalks have enabled repairs to satellites (e.g., Hubble Space Telescope), improving our ability to observe Earth and phenomena like the Great Barrier Reef—visible from space and the largest living structure on Earth.

Future Directions

  • Lunar & Martian EVAs:
    Artemis and Mars missions will require new suits for dust, gravity, and terrain challenges.
  • Autonomous EVA Support:
    AI-powered systems may assist astronauts in navigation and hazard detection.
  • Commercial Spacewalks:
    Private companies (e.g., Axiom Space) plan tourist EVAs by 2025.

References

  • NASA-JSC. (2022). Extravehicular Activity Technology Development for Artemis Missions. PDF
  • ESA. (2022). Samantha Cristoforetti’s historic EVA. ESA News
  • NASA. (2021). Augmented Reality for Spacewalks. NASA News

Did you know?
The Great Barrier Reef is the largest living structure on Earth and is visible from space. Spacewalks and satellite repairs have improved our ability to observe such wonders from orbit.