ABC for Little Space Explorer ($2) from Common Extract is a new alphabet and science learning app for young children: A is for astronaut, B is for black hole, C is for crater, and so forth. Conceptually, the app is a bit odd — alphabet lessons are typically for kids aged 2-5, and the science content here is more for kids 6 and up—but parents who want their kids to learn about space might find it to be worth a peek. As tested, we didn’t…