You can download the puzzle here: [Letter Size] [A4]. Print it double-sided in color on two pieces of card stock. If you cannot print in color, grayscale will do. If you have no card stock, plain paper will do.
Then fit all six spaceships on the red diamond without overlapping. You may flip them over.
The magician Chris Ramsay has a video about solving the Martian Diamond.
You can buy a sturdy plastic version of the Martian Diamond from Mr. Puzzle. This was Brian Young's exchange puzzle at the 2019 International Puzzle Party.