Self-Contained Isolated Breathing Apparatus
A human working in vacuum in a space suit labors under a great handicap. A spacesuit tends to stiffen into one favored shape and require effort to maintain arms and legs in some other position. Instead of going out into the lunar vacuum to maintain a piece of machinery, it can be brought inside where an inert atmosphere will not cause rust or corrosion to susceptible metals. A person can then do maintenance work wearing a Self-Contained Isolated Breathing Apparatus (SCIBA) instead of a space suit. This will improve capability and efficiency.
A SCIBA is a gas tight suit that keeps moist oxygenated air from mixing with the gas in a chamber filled with inert gas, hydrogen, or carbon dioxide as might be necessary for an industrial process. It has a supply of oxygen and a scrubber to remove carbon dioxide. The nitrogen or other inert gas is recycled. Sensors monitor the breathing gas mixture and vital signs so a worker can be warned of any failure of the life support. Telemetry from the sensors also alerts others in a position to rescue the worker in case of accidental failure.
An oxygen sensor for a SCIBA suit could be an Electro-galvanic fuel cell such as is used on Earth for scuba diving. The use for a SCIBA suit is less technically demanding because the SCIBA suit is always used at about the same pressure. Sensors for carbon dioxide, gas temperature, total pressure, humidity, heart rate, and body temperature would also be included.
A use for a SCIBA suit on Earth could be research involving molten titanium or other materials that need to be protected from a breathable atmosphere. It may be practical in cases in which a glove box does not easily provide access for sufficiently complex manipulation of an experiment.