Space Travel Poster (2015). Original from Official SpaceX Photos. Digitally enhanced by rawpixel. https://www.rawpixel.com/image/2257681/spacex-travel-posterFree Image from public domain licenseJPL Visions of the Future, Mars (2018) illustrated by Jet Propulsion Laboratory (JPL) / NASA. Original public domain image… https://www.rawpixel.com/image/10184944/image-art-space-cartoonFree Image from public domain licenseAurora Borealis in High Latitudes from the book William MacKenzie’s National Encyclopedia (1891), a colored… https://www.rawpixel.com/image/431526/free-illustration-image-science-fiction-astrology-galaxyFree Image from public domain license