Steadfast Enhancement 21 (prototype)

Steadfast Enhancement 21 is a prototype endurance, shield rating, and defense rating based enhancement.

Source
Steadfast Enhancement 21 can be obtained through crafting or as a mission reward.

Crafting
Steadfast Enhancement 21 can be crafted by Artificers with a skill of 380.
 * Artifice materials

The schematic can be obtained by reverse engineering a.

Mission reward
Steadfast Enhancement 21 can be obtained as a mission reward.
 * Mission reward

Reverse engineering
Reverse engineering this enhancement has a chance of teaching the schematic.