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 sample-return mission complexity and technical problems. One mission concept (provisionally named simply Mars Sample-Return) was originally considered by NASA's Mars Exploration Program to return samples by 2008, but was cancelled following a review of the program. A NASA-ESA concept mission was aborted in 2012. The United States' Mars Exploration Program, formed after "Mars Observer" failure in September 1992, supported a Mars sample-return. One example of a mission architecture was the "Groundbreaking Mars Sample-Return" by MacPhereson in the early 2000s. In early 2011, the National Research Council's Planetary Science Decadal Survey, which laid out mission planning priorities for the period 2013–2022 at the