Extravehicular activities (EVAs), commonly known as spacewalks, are essential but risky operations carried out by astronauts aboard the International Space Station (ISS). These spacewalks involve working outside the protective environment of the ISS, exposing astronauts to the vacuum of space, extreme temperatures, and radiation. Despite comprehensive planning and stringent safety measures, the possibility of an astronaut becoming incapacitated during an EVA remains a concern. In response, NASA and its partners have developed detailed procedures to manage such scenarios. This article outlines those procedures while referencing historical incidents, emerging technologies, and the latest advancements in space safety.

The Risk of EVA Incapacitation

Incapacitation during an EVA can occur due to several factors, including medical emergencies such as heart attacks, strokes, or dehydration, physical injuries, psychological stress, or spacesuit malfunction. The challenging environment of space exacerbates these risks, where astronauts rely entirely on their spacesuits for life support, mobility, and communication.

The bulky nature of the Extravehicular Mobility Unit (EMU) spacesuit further complicates the situation. These suits are designed for survival rather than comfort, limiting the astronaut’s dexterity and ability to respond to emergencies. The hostile vacuum of space, combined with the reliance on the suit’s life-support systems, means any incapacitation event requires immediate and precise action to ensure the astronaut’s safety.

Standard EVA Procedures and Preparation

Suit Checks

Before conducting an EVA, astronauts perform rigorous checks of their EMU suits. These checks ensure the suit’s integrity and functionality, including verifying life support systems, oxygen supply, communication links, and temperature regulation systems. The Extravehicular Activity Systems Manual provides a detailed checklist for astronauts to follow. Failures in any of these systems can potentially incapacitate an astronaut, necessitating robust preventative measures.

Communication Protocols

Maintaining constant communication between astronauts, the ISS, and mission control is critical during an EVA. Any interruption in communication can signal a problem. Continuous telemetry data is sent to mission control, providing real-time updates on the astronaut’s vital signs, suit pressure, oxygen levels, and other key metrics. This data allows ground control to detect signs of incapacitation even if the astronaut cannot communicate verbally.

Buddy System

Astronauts never conduct spacewalks alone. The buddy system ensures that another astronaut is always nearby to assist in case of an emergency. This system enables one astronaut to help the other with tasks or, if necessary, recover them in the event of incapacitation. NASA’s EVA Safety Procedures mandate that at least two astronauts participate in every EVA, reducing the risks associated with incapacitation.

Historical Incidents of EVA Emergencies

Luca Parmitano’s Near-Drowning Incident (2013)

One of the most well-known EVA incidents occurred in July 2013 when European Space Agency (ESA) astronaut Luca Parmitano experienced a life-threatening water leak inside his spacesuit. The leak caused water to pool inside his helmet, obstructing his vision and eventually covering his nose and mouth. Parmitano was forced to abort the EVA and make an emergency return to the ISS.

This incident demonstrated the importance of rapid decision-making and highlighted vulnerabilities in the EMU suit design. NASA conducted an in-depth investigation, and subsequent improvements were made to the EMU, including modifications to prevent water leaks and enhanced training for astronauts to respond to such emergencies.

Lessons Learned from Past Incidents

Parmitano’s incident underscored the importance of redundant safety systems and real-time monitoring. As a result of this and other incidents, NASA has continually refined its EVA procedures and spacesuit technology to improve astronaut safety. Procedures were updated to include more frequent checks on helmet ventilation and better real-time feedback from mission control, ensuring that similar issues are detected earlier in future spacewalks.

Identifying Incapacitation During an EVA

NASA’s Extravehicular Activity Contingency Procedures outline how to identify when an astronaut may be incapacitated. Common signs include:

• Loss of Communication: A failure to respond to radio communication is a critical indicator of a problem. While temporary communication glitches can occur, prolonged silence is an immediate cause for concern.
• Erratic or Lack of Movement: An astronaut who is motionless or drifting without control may be incapacitated. Erratic or uncoordinated movements can also signal a medical issue or suit malfunction.
• Abnormal Telemetry Data: Each spacesuit transmits telemetry data, including vital signs such as heart rate, oxygen levels, and suit pressure. Sudden changes or abnormalities in this data may indicate that the astronaut is in distress and requires immediate assistance.

Emergency Procedures for Incapacitated Astronauts

If an astronaut is determined to be incapacitated during an EVA, NASA has established clear emergency procedures to recover them safely:

1. Immediate Communication with Mission Control

The first step is to notify mission control of the situation. Mission control will guide the remaining astronaut(s) in stabilizing and recovering the incapacitated astronaut. Mission control has access to telemetry data and can provide real-time assistance based on the astronaut’s condition and suit diagnostics.

2. Assessment by EVA Partner

The astronaut’s EVA partner must quickly assess the situation. This assessment may involve:

• Visual Inspection: The partner astronaut will look for visible issues such as a suit puncture, equipment malfunction, or any abnormal behavior.
• Manual Checks: If communication is lost, the EVA partner may manually inspect the incapacitated astronaut’s life-support systems to ensure that oxygen is flowing and the suit is pressurized.
• Repositioning: In some cases, the astronaut may need to reposition the incapacitated astronaut to stop them from drifting away from the ISS.

3. Manual Assistance for Suit Operations

In an emergency, the EVA partner may need to manually adjust components of the incapacitated astronaut’s suit, such as adjusting oxygen levels or securing the helmet to prevent further leaks. NASA’s Extravehicular Activity Safety and Risk Assessment Plan provides detailed instructions for operating another astronaut’s suit in emergencies.

4. Recovery and Return to the ISS

The priority is to return the incapacitated astronaut to the safety of the ISS airlock. Several methods can be used to achieve this:

• Tether Reel-In: If the astronaut is tethered to the ISS, the EVA partner can manually reel them back toward the airlock.
• SAFER System Activation: Both astronauts are equipped with a SAFER unit, a small jetpack that can be activated to guide an incapacitated astronaut back to the airlock.
• Physical Assistance: If tethering and SAFER cannot be used, the EVA partner may have to manually push or carry the incapacitated astronaut back to the airlock, a task that requires considerable strength and precision in microgravity.

5. Reentry to the ISS

Once at the airlock, the astronauts must go through the depressurization process before safely reentering the ISS. Inside, the incapacitated astronaut will be attended to by onboard medical personnel or crew members under the guidance of mission control. NASA’s EVA Safety and Health Monitoring Protocols detail the steps for safely managing incapacitated astronauts after reentry.

Post-Incident Procedures and Debrief

After the astronaut is stabilized and back inside the ISS, a series of steps follow:

• Medical Assessment: The incapacitated astronaut undergoes a full medical evaluation to determine the cause of the incapacitation and to assess any long-term effects.
• Suit Examination: The spacesuit used during the EVA is examined for any malfunctions or issues that could have contributed to the incident.
• Debriefing: The astronauts and mission control team conduct a debrief to analyze what happened, how the response was managed, and any necessary improvements to EVA protocols.
• Incident Report: A formal incident report is filed to document the event and suggest any updates to protocols or equipment based on the situation.

Preventive Measures for Future EVAs

NASA has developed several measures to prevent incapacitation during future EVAs:

• Regular Health Monitoring: Astronauts undergo rigorous health checks before EVAs. Regular physical and psychological screenings help identify any potential risks before spacewalks. Pre-EVA evaluations ensure astronauts are fit to endure the physical and mental stresses of working in space.
• Suit Technology Upgrades: NASA is actively developing the next generation of spacesuits, such as the xEMU, which will be used in the Artemis program for missions to the Moon. These suits include enhanced mobility, improved life support, and real-time health monitoring features to reduce the risk of incapacitation.
• Training and Simulation Exercises: Astronauts undergo extensive training for EVA emergencies in facilities such as the Neutral Buoyancy Lab, where they practice responding to incapacitated astronaut scenarios in a simulated zero-gravity environment. This training ensures that astronauts are well-prepared for real-world contingencies.

International Collaboration and EVA Protocols

The ISS is a collaboration among various space agencies, including NASA, ESA, Roscosmos, CSA, and JAXA. Given the multinational nature of the ISS crew, EVA protocols must be standardized across all participating agencies. This ensures that astronauts from different countries are trained in consistent safety measures and can work together seamlessly in emergencies.

International Training Standards

Astronauts from different space agencies undergo joint training at NASA’s Johnson Space Center and other international facilities. During this training, astronauts practice handling emergency situations, including incapacitation events. Multinational crews are trained to follow NASA’s EVA contingency procedures, ensuring that spacewalks proceed smoothly and safely regardless of the astronauts’ nationalities.

Robotic Assistance and Autonomous Systems

As NASA and its partners continue to explore the possibilities of robotic assistance in space operations, there is growing interest in using robotics to assist in EVA rescue scenarios.

Robotic Rescue Systems

NASA is developing autonomous systems like Robonaut 2 that could eventually play a role in rescuing incapacitated astronauts during EVAs. Robonaut 2 is a humanoid robot designed to assist astronauts by performing routine tasks and responding to emergencies. In the future, such robotic systems could be deployed to help retrieve astronauts in distress or even perform basic medical assessments.

Drones and Remote-Controlled Devices

Other systems under development include drones and remotely operated devices that could assist with EVA operations. These drones could be used to guide or retrieve incapacitated astronauts in situations where the EVA partner is unable to perform the rescue alone.

Medical Response and Telemedicine

If an astronaut becomes incapacitated, onboard medical resources are limited. However, through the use of telemedicine, mission control can guide astronauts in providing medical care.

Onboard Medical Capabilities

While the ISS has a designated crew medical officer, that person may not be a professional doctor. Instead, crew members receive comprehensive medical training before their mission. In the event of an incapacitated astronaut, they are responsible for performing first aid or stabilizing the astronaut until further instructions are received from ground control. The ISS is equipped with basic medical supplies, such as defibrillators, first aid kits, and diagnostic tools.

Ground-Based Medical Support

NASA’s telemedicine system allows astronauts to consult with medical professionals on Earth in real-time. This system ensures that ground-based medical experts can offer guidance on how to treat the incapacitated astronaut. The use of telemedicine in space is becoming increasingly advanced, allowing for remote diagnostics and even complex procedures to be performed under Earth-based guidance.

Future EVA Technologies

NASA continues to develop new technologies to improve the safety and effectiveness of EVAs. Emerging innovations include augmented reality and artificial intelligence (AI) systems designed to assist astronauts during spacewalks.

Augmented Reality and AI Assistance

NASA is exploring the use of augmented reality displays in spacesuit helmets to guide astronauts through complex tasks during EVAs. These AR systems could provide step-by-step instructions, troubleshoot suit malfunctions, and even detect health issues. AI systems are also being developed to monitor astronaut health in real-time and provide emergency support if an incapacitation event occurs.

Advanced Spacesuit Technologies

NASA’s next-generation spacesuits, such as the xEMU, offer significant improvements in mobility, life support, and suit health monitoring. These suits are designed to reduce the risk of suit malfunctions and provide astronauts with better control over their environment, including real-time adjustments to oxygen levels and temperature.

Summary

Incapacitation during an EVA presents a significant risk to astronaut safety. NASA has developed detailed procedures for managing such emergencies, including real-time communication with mission control, manual suit adjustments, and various recovery methods. Lessons from past incidents, such as Luca Parmitano’s near-drowning, have driven improvements in spacesuit technology and EVA protocols.

Preventive measures, including enhanced training, suit technology upgrades, and advanced health monitoring systems, are continuously evolving to mitigate the risks associated with spacewalks. NASA’s collaboration with international partners ensures that astronauts from different space agencies are well-prepared to handle emergencies.

As space exploration continues to push boundaries, technologies such as robotic systems, augmented reality, and AI are likely to play an increasingly important role in ensuring astronaut safety during EVAs. Through these innovations, NASA and its partners plan to make spacewalks safer and more efficient in the coming decades.