Mars Exploration Rover 25, 2011, bringing the elapsed mission time to 6 years 2 months 19 days, or over 25 times the original planned mission duration. In recognition of the vast amount of scientific information amassed by both rovers, two asteroids have been named in their honor: 37452 Spirit and 39382 Opportunity. The mission is managed for NASA by the Jet Propulsion Laboratory, which designed, built, and is operating the rovers. On January 24, 2014, NASA reported that current studies by the remaining rover "Opportunity" as well as by the newer Mars Science Laboratory rover "Curiosity" will now be searching for evidence of
Crewed Mars rover rovers, because they need to know at least roughly where they are and where they are going to get to a destination. Dead reckoning was the method used by the Mars Pathfinder rover "Sojourner" for navigation. A GPS satellite network for Mars would mean a constellation of satellites in Mars orbit, but one alternative would be a surface based pseudo-satellites array. These devices would have to be emplaced with high precision, unless they were self-calibrating. An example of criteria for humaned Mars surface rover was expressed by NASA in the surface variant of the aforementioned SEV, in development in during