Squishy Taylor in zero gravity

Now that Squishy has been living with her father in Melbourne for some time she has grown close to her "bonus" sisters, the twins, Vee and Jesse, but she still is not sure about their mom, her father's new wife; however Squishy has a new passion (astronauts and space travel) and a new mystery to solve--who is the "spacewoman" across the street, why is she building a rocket on the roof of her apartment building, and how are they going to get through all the locked doors that are guarding this secret to find out?.