DEFINITION:

EVA systems are critical to every foreseeable human exploration mission, from in-space microgravity missions in LEO to planetary surface exploration. In addition, a launch, entry, and abort (LEA) suit system is needed to protect the crew during launch, landing, and cabin contamination/depressurization events, as well as the ascent/decent transition for planetary excursions. An EVA system includes hardware and software that spans multiple assets in a given mission architecture and interfaces with many vehicle systems, such as life support, power, communications, avionics, robotics, materials, pressure systems, and thermal systems.

Note: It is related with ESA’s TD 20-H

(Source: NASA TA6.2)

SUBDOMAINS:

1. Pressure Garment: The suit, or pressure garment, is the set of components a crew member wears and uses. It includes the torso, arms, legs, gloves, joint bearings, helmet, and boots. The suit employs a complex system of soft-goods and mobility elements in the shoulders, arms, hips, legs, torso, boots, and gloves to optimize performance while pressurized without inhibiting unpressurized operations. The LEA suit also contains provisions to protect the crew member from both nominal and off-nominal environments (e.g., gravitational, sound, chemical) encountered during launch, entry, and landing, as well as potential descent/ascent to planetary surfaces.
2. Portable Life Support System (PLSS): The PLSS performs functions required to keep a crew member alive during an EVA. These functions include maintaining thermal control of the astronaut, providing a pressurized oxygen (O2) environment, and removing products of metabolic output such as carbon dioxide (CO2) and water (H2O).
3. Power, Avionics, and Software (PAS): The PAS system is responsible for the EVA system’s power supply and distribution, collecting and transferring several types of data to and from other mission assets, providing avionics hardware to perform numerous data display and in-suit processing functions, and furnishing information systems to supply data that enables crew members to perform their tasks with more autonomy and efficiency.