From Star Trek: Theurgy Wiki
Starfleet’s Subspace Armor Field Tactical Integration (SAFTI) gear was a device used for personal protection that utilized subspace harmonics to generate a personal force field. This device saw frequent use in early 25th century conflicts before being replaced by the Multiphase Integrated Tactical Engagement System (MITES) in the 2460’s.
Origin of the SAFTI device
SAFTI gear began life as a jury-rigged assembly of subspace transceiver assemblies and emitter coils. During the Dominion War Master Chief Petty Officer William Robert "Billy Bob" O'Connell played with the concept based off a story he heard of an officer building such a rig on a malfunctioning holodeck. The small hexagonal subspace transceiver assemblies could be found in any combage. Using a thin tightly coiled wire made from a conductive metal with a low resistance such as copper or iron, he attached one end to the control circuit of the combage’s subspace transceiver assemblies and the other to the RF transceiver to shape the device’s protective energy field. These early models projected a field in a variety of forms, ranging from spherical and hemispherical to conical, planar, curved planer or elliptoid. He discovered that a fully charged combage was able to generate an energy field with a phase shift of approximately .04 millicochranes for up to 15 seconds. This was sufficient to deflect slow physical projectiles (rocks, arrows, shots from primitive projectiles) and low-power directed energy attacks (primitive sonic or laser weapons) but faster or significantly more powerful projectiles (such as advanced assault firearms or modern phasers and disruptors) depleted the force field’s energy quickly and in some cases penetrated it with little or no difficulty.
After the Dominion War, Master Chief O’Connell tinkered with the concept when he could, but didn’t see it as a priority until November of 2380, when the officers and crew of the USS Theurgy discovered the sinister parasites that had taken over Starfleet Command. After the damage inflicted by Task Force Archeron led by the corrupted Admiral Sankolov, O’Connell didn’t have much time to work on the device and recruited his friend and shipmate Senior Chief Petty Officer Calvin Reagar to assist. As time allowed, they gradually turned a collection of combadges, coiled wire, sarium krellide power cells, belts, and harnesses into a portable unit capable of projecting a protective force field that was nearly skintight.
Mark One SAFTI
As of March 2381, the rig was capable of protecting a standard sized person for over ten minutes from weak attacks like physical blows or slow moving projectiles. It could resist shots from phasers, disruptors and other particle beam weapons for one fifth of the time assuming the weapon was fired at standard settings. A beam that could disintegrate a human could get through in seconds.
Early problems with the SAFTI
As untested prototypes, the Mark I SAFTI had its share of problems. For the raid on Starbase 84, each unit was constructed by hand with various results. Certain rigs would use up their power supply much faster, in some cases at twice the normal rate. Mild cases of dizziness or nausea were reported due to the effect of the subspace harmonics so close to the central nervous system. In one case, a user of the device discovered that air had a hard time getting through the force field forcing the user to use it sparingly. These problems were addressed and corrected in later versions but during the Theurgy’s raid on Starbase 84 in March of 2381, dependence on the unit for protection came with considerable risks.