Skill (Historic)

Being comparable to talents and talent trees of other MMORPGs, Skills improve existing abilities and/or grant passive bonuses by spending skill points  on them. Skills have a direct influence on the overall strengths of your character and, along with your traits and Captain Specializations, are a key to adapting your character to your play style. Additionally, some skills also unlock the option to craft new Training Manuals for your Bridge Officers, granting them higher ranks of abilities.

Skills are separated into space & ground skills. Space skills are subgrouped into "Tactical Systems", "Engineering Systems", and "Science and Operation Systems". Ground skills consist of only one career path-specific group ("Tactical/Engineering/Science Officer"). Additionally, there are five columns of skills, from Lieutenant on the left, to Admiral on the right. While skill points  can be immediately spent on skills as they are earned via gameplay, you must hold the required player rank in order to access the next column of the skill tree.

Upgrade levels
Each skill has 9 upgrade levels whose skill point costs depend on the rank (i.e., column) of the skill: At upgrade level 9, some skills also unlock the option to craft Training Manuals for Bridge Officers. While players continue to earn skill points indefinitely, the amount spendable in the skill tree is capped at 366,000, which is reached at rank Vice Admiral/Lieutenant General (level 50). A maximum of 300,000  can be assigned to space skills, as at least 66,000   must go into ground skills. The bonus granted per level diminishes (shown below), i.e., the first three upgrade levels grant +18 bonus each, the second three +10 each, and the last three only +5 each (3x18 + 3x10 + 3x5 = 99 bonus):
 * 1,000  for Lieutenant
 * 1,500  for  Lt. Commander /  Centurion
 * 2,000  for  Commander /  Subcommander
 * 2,500  for  Captain /  Commander
 * 3,000  for  Admiral / General

The absolute improvement a bonus increment grants depends on each individual skill. Starship Energy- and Projectile Weapon Specialization, for instance, both grant ~0.02% critical hit chance and ~0.25% critical severity per bonus increment for their respective weapon type. Starship Weapon- and Shield Performance on the other hand, both grant 0.1% power increase per bonus increment for their respective systems. The exact absolute bonuses for most other skills are not well known and have never been disclosed by the developers.

Space
The space portion of the skill tree is the same for each career path.

Ground
The ground portion of the skill tree is specific for each career path.

Science Officer
=See also=
 * List of Training Manuals craftable by captain: A list of skills, that unlock the option to craft Training Manuals to teach Bridge Officers new ranks of abilities.
 * STO Character Planner @ STO-Academy.com (including skill planner)