Here you can find a list of where all the Space Ship parts are in the game. Note that the Space Ship parts only show up after you have visited "Omega" with Franklin.
Omega is first contacted through a Strangers and Freaks icon after Main Mission #21 (Fame or Shame). He can be found in the western section of Sandy Shores. Once you go and visit him you'll get a short scene and then you will be able to find Space Ship parts.
Note that when you are close to the part, you will hear a faint humming noise. This signifies that you are close, and the humming will get louder the closer you get.
Our directions are pretty solid but in case you need even more help by all means check out the videos we have for each piece, where we go through every single piece and show you how to get it and where it is on the map. Enjoy and happy hunting!
Spaceship Part #1
You can find this part at the Port of South Los Santos, south of Route 20. It is fairly easy to find: look for two humongous spheres (water containers, I believe - and yes there is a joke in there somewhere). In the middle of them you can find a ladder heading upward. Follow it up, hang a right, and climb the ladder you find. Now you can jump on a pipe going between the two building. In the middle is the part.
Spaceship Part #2
Now this one is tricky, since it is located at the Los Santos International Airport. Heading there without owning a hangar will get you a three-star wanted level. If you do own the hangar you are good, but that costs quite a bit. The part is behind the hanger in the southeast corner. You can find it behind the hanger near a dumpster.
If you are going in with the cops on you, it is best to drive through the barricades, drive around the hangers, look for it, grab it, and then drive out. Get out of the wide-open airport area and lose the cops in town.
Spaceship Part #3
This one is somewhere no one would think to look: under the ocean! Well, actually they hide quite a few things under the ocean. Head to the Port of Los Santos and onto the dock to the east. Now walk down the east side of the dock until you second to last ladder down in the water.
Dive off from here and search the nearby seabed to the right. You'll see some metal wreckage on the seafloor and the part will be amongst it.
Spaceship Part #4
This one isn't too bad. Head to the Murrieta Oil Field (the southeast part of the map). Now down along the coast are a number of small islands. The second one from the left has this spaceship part on it, hanging out on a rock. Swim out there and get it.
Spaceship Part #5
This one is fairly close to #4. Head down the coast south of the Elysian Fields Freeway. On the west portion of the coast you'll find a section of the beach sunken in (and wet) due to a drainpipe. Follow this up to the drainpipe to find the part chilling behind the grate.
Spaceship Part #6
Head to the intersection of Dutch London Street and Signal Street in southern Los Santos. Nearby you should see some metal artwork of several towers. Epic folk art! Head over there and you will find a gate to get to the base of the towers. The part is to the right.
Spaceship Part #7
This one is tricky. It is located in the Murrieta Oil Field area up near the north. Follow El Burro Blvd. up about halfway until you get to an oil manufacturing plant that has three circular buildings, an oil well, and several large tin buildings. Along one of the large tin buildings is an open green railroad car. The part is inside of it. Three workers often hang out by the open railroad car.
Spaceship Part #8
This part is pretty easy to find. Head to the medical center at South Los Santos (on the corner of Crusade Road and Capital Blvd). Near the emergency entrance is a ladder. Climb up it. Find another nearby ladder and climb it as well to the emergency helipad. The part is up there.
Spaceship Part #9
This one isn't too hard. You want to find the hobo camp under the Olympic Freeway (Power Street and Innocence Boulevard). Going north, head under the freeway and check out the left-hand side. The part is by the stairs leading down to the substation, behind a wall near a hobo.
Spaceship Part #9
-- Video coming soon --
Spaceship Part #10
This one is fun. Head to Vespucci and to the intersection of Prosperity Street (The street coming up through all the waterways) and Palamino Ave. Now head north from there. You should see a huge billboard by a liquor store. Head to it and find the stairs going down nearby leading to a ladder that lets you climb up to the billboard. The part is up there.