Robotic missions to the red planet

[bearnard1616]

As you may probably know, all robotic missions humans sent to Mars were not enough successful, if to say frankly.
I wanna hear your thoughts and views, why this technique did not manage with aims?

 

[JeetsN123]

Not successful? They went great, Spirit and Opportunity were expected to last 90 days but managed 6 years in Spirit's case and 14 in Opportunity, during which they learned a lot about Mars's composition. I would call that a resounding success.