The ship has a single jump drive built in, and then it merges with these "boosters" for a total of 3 drives @ 6000 km, which is enough for me to planet hop in one or two jumps. I then detach the boosters (via merge blocks) and explore the area in just the ship, without the extra weight and size of those additional drives. So they are kinda like the FTL version of the boosters used on the Space Shuttle back in the day.

Nice is it running two or more Jump Drives?