Actually, NASA is working on placing "rat's" on Mars. A "rat" is a Rock Abrasion Tool, a robot that will dig the rocks for geological study. After 9/11, as a gesture of sympathy, I suppose.
quote:
NASA Headquarters just approved putting an American flag on the rock shield of the rock abrasion tool.
The entire story is here: http://spaceflightnow.com/news/n0205/02marsrats/
The part about the American Flag is in the last paragraph.
Also, there is a photo of the flag on the Viking explorer and it shows Mars' background. It was only used in order to get the proper color of the Martian landscape, using the filters in spectral leaks.
http://history.nasa.gov/SP-425/p136a.htm
The explanation is in this link.
http://history.nasa.gov/SP-425/ch39.htm