Thank you, that is actually a great picture! Most pictures of the rovers fail to depict the difference in size between Sojourner (the Pathfinder rover), Spirit

Thank you, that is actually a great picture! Most pictures of the rovers fail to depict the difference in size between Sojourner (the Pathfinder rover), Spirit/Opportunity and Curiosity which is the largest to date. Besides rovers, on the surface there are also several landers, sent by USA, USSR, UK and ESA. A complete list of human made objects landed on extra terrestrial bodies is here: https://en.wikipedia.org/wiki/List_of_landings_on_extraterrestrial_bodies https://en.wikipedia.org/wiki/List_of_landings_on_extraterre... I suspect the above link just made someone's week end ;-) UPDATE On a separate note, it would be very interesting if future (manned or unmanned) missions could visit artifacts sent by previous missions and assess their state / decay over time. The only example that I know of is Surveyor 3 (moon unmanned lander) which was visited by the Apollo 12 mission a couple of years later. For some reason, my dream is one day to be able to travel to Mars and visit Spirit in its final resting place at Troy[1]. [1] http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA12205 http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA12205