Dear All Please forgive an oldie from jumping in! I recall two things from the original Mars Viking Lander. [1] there was an Astrobiologist at JPL who had the formidable task of testing the after landing viability on Mars of various microbes, viruses, etc. Because we did not wish to contaminate Mars, and we did not want to have one [or more] slide off the lander only to be scooped up and tested onboard with the result of our declaring Mars had a similar life form to earth`s,,heavens it could be ours. One of the most puzzling onboard results at that time were some of the soil content results. Though no exotic minerals were found, the Martian samples tested differently [ or with varying results] than from similar minerals on Earth. I do not know if the Why was ever found. My husband and I very much enjoy receiving your emails and wish we were closer in order to join you folks for a star party. Congratulations especially, for your outreach, your wonderful senses of humor, and your tolerance of folks chiming in on a topic from my years in the aerospace industry, and my husbands at Griffity Observatory. Jan & Stan Seeberg Vancouver [Washington] Sidewalk Astronomers.org