Continuity mistake: Don West is wearing Dr. Smith's necklace, even though it was lost in the storm. The necklace is then not there or removed in the next shot. (00:31:30)
Continuity mistake: John and Will start putting stones down as a memorial for those lost on the Resolute. He places the first one and says to Will that he talked to a woman named Angela, and she lost her husband in the attack. When John says this, Will looks down at the big rock they are in front of or the rock in John's hands. Then in the next shot, Will is suddenly looking up at John again. (00:36:24)
Answer: The Fortuna didn't have an Alien Engine. The cover story was the Fortuna was to explore Alpha Centauri but it was exploring the rift. The rift is what the Alien Engine creates and explains how the Fortuna was able to travel to a distant planet (what you call "galactic travel").
Bishop73