Concept Breakdown

1. Definition

Spacewalk (Extravehicular Activity, EVA): Any activity performed by an astronaut outside a spacecraft in space. EVAs are crucial for spacecraft maintenance, scientific research, and assembly of structures like the International Space Station (ISS).

2. Historical Context

  • First Spacewalk: Alexei Leonov (USSR), March 18, 1965, 12 minutes.
  • First American Spacewalk: Ed White, June 3, 1965.
  • Longest Spacewalk: Anatoly Solovyev holds the record with 16 total EVAs, over 82 hours.

3. Purpose of Spacewalks

  • Maintenance: Repairing and upgrading spacecraft and satellites (e.g., Hubble Space Telescope).
  • Assembly: Building structures in orbit (e.g., ISS modules).
  • Scientific Experiments: Deploying instruments, collecting samples, testing materials.
  • Emergency Response: Addressing unexpected issues (e.g., fixing solar panels).

4. Spacewalk Procedure

a. Preparation

  • Suiting Up: Donning the Extravehicular Mobility Unit (EMU), a self-contained suit providing life support and mobility.
  • Pre-breathing: Breathing pure oxygen to prevent decompression sickness (“the bends”).
  • Checklist Review: Detailed procedures for tasks and contingencies.

b. Execution

  • Airlock Depressurization: Gradually reducing pressure to match vacuum of space.
  • Tethering: Astronauts are always attached to the spacecraft via tethers for safety.
  • Task Performance: Using specialized tools and handrails.

c. Return

  • Airlock Repressurization: Restoring normal pressure.
  • Suit Doffing: Removing the suit and post-EVA medical checks.

5. Equipment

  • Extravehicular Mobility Unit (EMU): Provides oxygen, temperature regulation, communication, and protection from micrometeoroids.
  • Safety Tethers: Prevent astronauts from drifting away.
  • Manned Maneuvering Unit (MMU): Jetpack used for untethered movement (now rarely used).
  • Toolkits: Custom tools for specific tasks.

6. Challenges

  • Microgravity: Makes movement unfamiliar and tiring.
  • Temperature Extremes: Ranging from -250°C to +250°C.
  • Radiation Exposure: No atmospheric shielding.
  • Communication Delays: Limited real-time support from Earth.
  • Physical Strain: Suits are bulky; tasks require strength and dexterity.

7. Recent Breakthroughs

a. New Suit Technologies

  • xEMU (Exploration Extravehicular Mobility Unit): NASA’s next-gen suit for Artemis missions, offering improved mobility and dust protection.

b. Robotic Assistance

  • Robotic Arms: Canadarm2 and Dextre on the ISS reduce astronaut workload and risk.

c. AI-Driven Spacewalk Planning

  • AI Algorithms: Used to optimize EVA plans, predict risks, and assist in real-time decision-making.
    • Reference: NASA’s Artemis program is integrating AI for mission planning (NASA, 2022).

d. Material Science

  • Smart Materials: Self-healing polymers being tested for suit puncture repair.

e. AI in Drug Discovery for Space

  • Artificial Intelligence: Used to discover new drugs and materials for astronaut health and spacecraft durability, considering unique space environment challenges (Zhou et al., 2023, npj Digital Medicine).

8. Surprising Facts

  1. Astronauts’ Fingernails Can Fall Off: Due to repeated pressure and friction inside gloves, some astronauts have lost fingernails during EVAs.
  2. Water Leaks Are a Top Hazard: In 2013, Luca Parmitano’s helmet filled with water during a spacewalk, nearly drowning him.
  3. Spacewalks Can Alter DNA: Exposure to microgravity and radiation during EVAs can cause detectable DNA changes in astronauts.

9. Diagrams

Spacewalk Suit Diagram Figure 1: Components of the Extravehicular Mobility Unit (EMU)

ISS Spacewalk Figure 2: Astronaut performing a spacewalk outside the ISS

Glossary

  • EVA (Extravehicular Activity): Any activity performed outside a spacecraft.
  • EMU (Extravehicular Mobility Unit): Spacesuit designed for EVAs.
  • Airlock: Compartment allowing astronauts to exit/enter spacecraft without depressurizing the entire vehicle.
  • Tether: Safety line connecting astronaut to spacecraft.
  • Microgravity: Condition in which objects appear weightless.
  • Decompression Sickness: Illness caused by rapid decrease in pressure, leading to nitrogen bubbles in the blood.
  • Radiation: High-energy particles in space that can damage biological tissue.
  • Robotic Arm (Canadarm2): Robotic manipulator on the ISS for moving equipment and assisting astronauts.
  • Smart Materials: Materials that respond to environmental changes, such as self-healing polymers.
  • AI (Artificial Intelligence): Computer systems simulating human intelligence for tasks such as planning and diagnostics.

Most Surprising Aspect

The most surprising aspect:
Spacewalks can cause lasting biological changes, including DNA mutations, due to combined exposure to microgravity and cosmic radiation. These changes may have implications for long-term human spaceflight and health.

Recent Research

  • Zhou, Y., et al. (2023). “Artificial intelligence in drug discovery for space medicine.” npj Digital Medicine, 6, Article 45.
    Link
  • NASA Artemis Updates (2022): AI integration for EVA planning and astronaut health monitoring.
    NASA Artemis

References

  1. Zhou, Y., et al. (2023). Artificial intelligence in drug discovery for space medicine. npj Digital Medicine, 6, Article 45.
  2. NASA Artemis Program. (2022). Artemis Overview
  3. NASA. (2021). Spacewalks and EVAs

End of Study Notes