I decided to do a finger splint for the astronauts because it might be easy to trip and fall in low gravity on Mars or to jam a finger while fixing their space ship. The splint will help the hurt finger heal and it is thin enough that the astronaut can still wear a space suit.
I made the splint a tube with rounded edges to be comfortable. The splint should be printed from a plastic that is a little bit soft and flexible. I measured my mom's index finger to design the splint but the astronauts could change the size to fit the finger that is hurt before they print it.