Space Dogs — Susan Meddaugh

When Helen and Martha help T.D. write a comic book for his science project, they suddenly find themselves written into the story! Spacedog Martha tries to evade the pesky spacecats and their radioactive hairballs, while Commander Helen leads a mission to retrieve all of the socks that have gotten lost in space. Just when Martha thinks her space adventures are over, she wakes up on the Planet of Dogs. As one of dozens of space dog clones, Martha must use her new alien powers on a special mission to Earth.