To begin to explore the cloud planet—nicknamed for the thick swaths of carbon dioxide and sulphuric acid that encircle it—Landis proposed a solar-powered airplane that could navigate the atmosphere and even a land-sailer that could survive the planet’s extreme surface climate. He developed the concept in more detail at another conference in 2003, where he claimed that “robotic exploration of Venus could potentially lead to the development of a human mission to explore the clouds of Venus by aircraft,” concluding that “ultimately we could even envision colonization of the Venus atmosphere.”