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 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 spaceship.

Detailed walkthrough
4 fusion cores can be found in the area: If you insert 4 fusion cores instead of 3, Dara and the rest of the Hubologists will explode on the spaceship ride. Either way, you will complete the quest.
 * 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 is 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 although a carefully timed jump from the floor above works too.
 * 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 spaceship ride

Bugs
Make sure the Hubologists have entered the space ship before activating the ride. Quest might not trigger completion otherwise.