Therum is a main quest, you cannot return to the Normandy until you have solved the entire quest, in this case, before you have saved Liara.
Get into the Mako and bring up the Map. > Return to Normandy.
@holger1405 thank you for your response.
Though for some unknown reason this does not work.
I am at Therum: Ruins.
I even moved the Mako back to where I originally began when commencing this mission on Therum, but to no avail.
The option to go back to Normandy by pressing the "square" PS4 controller button is not available, neither in the map nor even playing the game.
?
Therum is a main quest, you cannot return to the Normandy until you have solved the entire quest, in this case, before you have saved Liara.
