Picked this one up at the Dollar General.
The science is sketchy, the premise illogical (converting a erector-set space station into a spacecraft? Give me a break, which is what would happen to the space station the moment any major force, such as thrust, was applied), the aliens FTL anemic (first signal was detected 50 LY away, which means it was 50 years ago! The next signal was 30 LY away, yet the older signal reached earth BEFORE this one! If they really were travelling FTL we wouldn’t know it until they arrived as they would beat their Light-Speed Signals!), and the characters straight out of central casting.
Don’t bother. The writing style isn’t horrible, but the science behind it left me colder than the dark side of the Moon.