Solution based on John Selck's maps. It uses his teleports' nomenclature. Since Mercenary I inventory is limited to 10 items, please leave particular of them when you are asked to.
1) Buy Dominion Dart after you crash on Targ.
2) Fly to 09-06 and get key.
Go through a teleporter in the room with the MEDICAL SUPPLIES to get the PHOTON EMITTER.
Get the POWER AMP. Exit the hangar and leave the key.
3) Fly to 81-35 and get COLONY CRAFT key.
4) Fly to COLONY CRAFT 08-08 and get key from the lowest floor.
5) Fly to 03-00, leave the POWER AMP and enter hangar for key.
6) Fly to 09-05 and get key, key.
Go north to the hall of teleports and use the first one (random teleporter).
Walk through it's door and exit backwards. After exiting make a few steps backwards
and take a look around. As soon as you are in a dark-orange room with
door on the left and on the right,
you will be in the correct location, in the restricted 03-15 hangar (I don't know of a better way to get there).
7) 03-15. Walk through door to the right and continue north to get key.
Now one door to the south and two to the west to get to the "Ti" two way teleporter
which will send you to **-** hangar. Get the NOVADRIVE and return to 03-15 via the "Ti" teleporter.
Walk one door to the east and run north past the door with a skull (you won't die :) ).
It's a dark room, that's why we still carry the photon emitter. Board the INTERSTELLAR SHIP, exit the hangar. Since you have already collected NOVADRIVE you can press Y and say goodbye to Targ.
THE END !
solution by Szymon Ender "Enjo"