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
Mars Surveyor 2001 Lander is identical to that of the Mars Polar Lander, which had been intended to be the first of a series of low-cost "Mars Surveyor" landers sent to Mars. Prior to mission cancellation, cost overruns and technical problems caused the Lander design to be rescoped, and the planned large Athena rover was replaced by a small rover duplicating the "Sojourner" which was a part of the Mars Pathfinder mission. (The Athena did later make it to Mars, however, with two such rovers making up the Mars Exploration Rover Mission of 2004. The second of these, MER-B "Opportunity", landed at Mars Surveyor