Greetings, that trait can only be obtained by purchasing one of the following starships from the store, Andorian Chimesh Pilot Escort, Lethean Nemosin Pilot Escort and the Dewan Ikkabar Pilot Escort.
Once you have completed ship mastery and unlocked the starship trait you can then use it with any ship of your choice, so yes you will be able to use it with your Temporal Science Vessel..
heres a link to the page on stogamepedia for you to peruse = https://sto.gamepedia.com/Trait:_Improved_Gravity_Well
Hope that helps you..
Answers
Once you have completed ship mastery and unlocked the starship trait you can then use it with any ship of your choice, so yes you will be able to use it with your Temporal Science Vessel..
heres a link to the page on stogamepedia for you to peruse = https://sto.gamepedia.com/Trait:_Improved_Gravity_Well
Hope that helps you..