PLSS meaning in Governmental ?

What is Primary Life Support System mean?

A primary (or portable or personal) life support system (or subsystem) (PLSS), is a device connected to an astronaut or cosmonaut's spacesuit, which allows extra-vehicular activity with maximum freedom, independent of a spacecraft's life support system. A PLSS is generally worn like a backpack. The functions performed by the PLSS include:

Regulating suit pressureProviding breathable oxygenRemoving carbon dioxide, humidity, odors, and contaminants from breathing oxygenCooling and recirculating oxygen through the pressure garment, and water through a Liquid Cooling and Ventilation Garment or Liquid Cooling Garment.Two-way voice communicationDisplay or telemetry of suit health parametersTelemetry of an indicator of the wearer's immediate health (e.g. heart rate)

The air handling function of a PLSS is similar to that of a diving rebreather, in that exhaled gases are recycled into the breathing gas in a closed loop.

When used in a microgravity environment, a separate propulsion system is generally needed for safety and control, since there is no physical connection to a spacecraft.

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