The Robinsons Were Here - S1-E4
Continuity mistake: Penny is holding an envelope in her hands, then turns around to follow the siblings and the envelope is gone. Just a cut later Penny has the envelope back. (00:32:30)
The Robinsons Were Here - S1-E4
Revealing mistake: After going beyond the perimeter fence for the first time, the children initially find the flowers that bloom when they each clap. When the robot motions to clap, you can see its left hand lost to the CGI flowers.
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