Trip to the Stars

Trip to the Stars is a side quest in the Fallout 4 add-on Nuka-World.

Quick walkthrough
Gather 5 spacesuit costumes from the Vault-Tec: Among the Stars area of the Galactic Zone and bring them to Dara Hubbell. Follow the Hubologists to the Nuka-World junkyard or tell them you have cleared it already. Once there, collect the power distributor and some fusion cores and go to the UFO spaceship ride. Adding three cores, as Dara suggests, will result in a good end to the quest. However, adding the fourth core will result in the death of the Hubologists. If you choose to not kill them, Dara gives you 100 ammo for the alien gun, and all the Hubologists relocate to the large barn northeast of the UFO.

Detailed walkthrough
4 fusion cores can be found in the area:
 * In the subway car with a lantern hanging by the door. The car is at the bottom of the ramp from the spaceship.  The core in on a shelf to the right as you enter.
 * In the nearby barn, there is a generator with a core.
 * In the same barn, the hanging gondola car has a core sitting on its floor. You may need power armor and a jet pack to reach it.
 * In a mounted Bears mouth, in a tunnel with some crickets and landmines.

Reward

 * Hub's Alien Blaster received from Dara Hubbell
 * 100 Alien blaster rounds received from Dara Hubbell if the Hubologists survive the UFO ride