In a retro 70s book art style, envision an alien spacecraft gracefully landed on the rocky terrain of an exoplanet. Two astronauts, clad in vintage space suits, explore the landscape with a sense of wonder. Looming in the vibrant sky is a majestic green gas giant, casting an otherworldly glow over the scene. The spacecraft is sleek and reflective, with intricate designs reminiscent of classic science fiction aesthetics. The background is dotted with distant stars, adding to the sense of cosmic adventure. A subtle, swirling mist hovers around the planet's surface, enhancing the mysterious atmosphere.