Though general awareness around it may be low, space cyberattacks are an increasingly urgent problem given the vital role that space systems play in the modern world. Open-source or public discussions about it typically revolve around only a couple generic scenarios, namely satellite hacking and signals jamming or spoofing. But there are so many more possibilities. The report offers a scenario-prompt generator—a taxonomy of sorts, called the ICARUS matrix—that can create more than 4 million unique scenario-prompts. We will offer a starting set of 42 scenarios, briefly describing each one, to begin priming the imagination-pump so that many more researchers can bring their diverse expertise and perspectives to bear on the problem. A failure to imagine novel scenarios is a major risk in being taken by surprise and severely harmed by threat actors who are constantly devising new ways, inventive and resourceful ways, to breach the digital systems that control our wired world. To stay vigilant, defenders likewise need to be imaginative to keep up in this adversarial dance between hunter and prey in cybersecurity. More than offering novel scenarios, we will also explore the drivers of the space cybersecurity problem, which include at least seven factors we have identified. For instance, the shared threat of space debris would seem to push rational states and actors to avoid kinetic conflicts in orbit, which weighs in favor of cyberoperations as the dominant form of space conflicts. Outer space is the next frontier for cybersecurity. To guard against space cyberattacks, we need to understand and anticipate them, and imagination is at the very heart of both cybersecurity and frontiers. A free, digital version of the report can be downloaded here: https://spacecybersecurity.org