The Jet Propulsion Laboratory (JPL) shared a series of travel posters a little while ago. I think they go great with our theme of Destination Deep Space.
The posters are available to download and print at https://www.jpl.nasa.gov/visions-of-the-future/.
These are high resolution images intended to be printed as large posters. They are nice enough to get framed and hang in your home as artwork.
Check with local art stores and printers about getting full size prints made for you team, your school, and for them to sell through their business.