Life Support Systems

All space vessels and facilities require extensive life-support systems to support their crews.  Life support systems maintain a single environment suitable for most Federation races, although some species, like the Benzites, may require supplemental devices such as respirators to help them breathe.  The technology used is basically the same on all Starfleet facilities.

Life support systems have to meet the highest safety standards, and are designed with multiple backups and redundant safety checks that protect the crew even in the the event of multiple systems failures.  For instance, on Galaxy class starships, the atmospheric support system to the main bridge features seven independent safety interlocks.  The safety net includes mutually supportive parallel trunk lines and a reserve utilities distribution network for limited supplies of basics such as air, power, and water.  Gravity is not included in the safety net as it is created by generators throughout the ship.  Life support equipment centers are on decks 6, 9 and 13 in the primary hull, and decks 11, 21, 24, and 34 in the engineering hull.  In the rare event of a systemwide failure, there will still be sufficient atmosphere to maintain the crew for several hours.  The exact length of time will depend on the number of personnel on board.

On Starfleet vessels, an oxygen-nitrogen atmosphere is maintained for Class-M life forms as a shipwide norm.  This gives the crew an ambient temperature of 26 degrees celsius, and 45 percent relative humidity at a pressure maintained at 101 kilopascals.  The atmosphere consists of 78 percent nitrogen, 21 percent oxygen, and one percent trace gases.  On Galaxy-class ships, some 10 percent of the habitable living space can be adjusted to classes H, K, or L environmental norms without hardware modifications.  Another two percent of the living space is equipped for swap out to classes N and N(2).  If necessary, the entire ship can be altered for natives of classes H, K, or L planets by replacing the atmospheric processor modules, but this is a major undertaking and must be done during a starbase refit.

Atmospheric processors are located throughout the ship at a rate of about two redundant units for every 50 cubic meters of habitable ship's volume.  The units combine carbon-dioxide removal with oxygen replenishment; most of their work is accomplished through the use of photosynthetic bioprocessors.  Normal maintenance routines call for each side of the parallel system to take the load in 96-hour cycles.  If necessary, individual units can be switched between the two sides of the system for greater flexibility and redundancy.  The third backup atmospheric net can provide up to 50 percent of the system capacity for as long as 24 hours.  In addition, if the main and reserve atmospheric systems fail, contingency atmospheric modules located at most corridor junctions can provide a breathable atmosphere for approximately 30 minutes.  This gives the crew vital time for evacuation, repair, or shelter-seeking.  On a Galaxy-class starship, hundreds of simple synthetic gravity generators provide normal Class-M gravity; they are tied in to the inertial dampers to counteract acceleration effects.  In an effect that is very similar to the one used in tractor beams, each gravity generator creates a gravity field by using a controlled stream of gravitons that are generated by a superconducting stator, rotating at speeds over 125,540 rpm.  They are powered by energy tapped from the electro-plasma system (EPS).  The stator is built of thoronium arkenide and is suspended in pressurized chrylon gas in the center of a hollow sealed chamber of anicium titanide 454.  The chamber is 50 centimeters in diameter and 25 centimeters tall.  Each gravity generator provides a graviton field of only a few picoseconds, and because of the short decay time generators are located at approximately 30-meter intervals.  Thus, the ship at large includes two networks each of 400 generators in the primary hull, and two more networks of 200 generators in the engineering hull.  The generators are tied together by small waveguide conduits to allow 'field bleed' in cases of extreme maneuvering and inertial movement.  Each stator is built in a suspended state, and is maintained with a synchronizing EPS energy pulse every hour or so.  In the case of EPS loss, the stator will provide an attraction field for up to 240 minutes.  During this time, gravity should only dip down to about 0.8gs.  Sinesopidal ribs on the inner surface of each generator's sealed cylinder absorb motions with an amplitude up to six centimeters per second.

Since no starships can carry the required amounts of food and water for extended missions, recycling and waste reclamation are essential.  Aboard Galaxy-class ships, complexes on decks 6, 13, and 24 include treatment and recycling units for liquid waste, all of which is recycled into fresh water, food replication, or general matter replication.  Solid waste is handled in processors on decks 9, 13, and 34.  These processors scan the waste material for its composition, and route items to the most practical recycling system.  Some 82 percent of all solid waste can be recycled mechanically, but any material that cannot be directly recycled either this way or chemically - including about five percent of all waste classified as hazardous - is set aside for general matter replication.

Modern life support systems can cope with a number of situations that would have been fatal on earlier starships and space stations.  Most notably, hull breaches are automatically contained by forcefields.  Under normal circumstances, life support is extremely reliable.  Starfleet calculates that, barring a serious accident, life support failure should occur only once every 500 years.  Despite the redundancy built into all starship systems, designers have to allow for emergency backup systems in case of system loss or damage.  Galaxy-class starships are provided with two independent safety systems - a 30-minute shipwide lighting a power backup system to cover repair time if needed, and 52 designated emergency shelters, such as the forward observation lounge at deck 10, section 1.  The backup system includes 425 of the corridor junction modules cited earlier, which, in addition to atmospherics, include emergency lighting and batteries.  The shelters of dedicated and protected power trunks, and are designed to sustain up to 65 crew members for up to 36 hours.  They also include 24 hours' worth of air, water, food, and power supplies, independent of even the backup, as well as two emergency pressure garments.

Even in the event of an emergency, it is a highly unlikely that life support will fail throughout the ship.  In the event of a partial systems failure, the commanding officer may opt to evacuate the crew from the affected sections.  In case of a severe failure, the crew may be evacuated or, on certain classes of starship, the commanding officer may initiate a saucer separation, with the entire crew taking refuge int he unaffected section.