NASA has said it is ending its attempts to regain contact with the Mars Exploration Rover Spirit. A transmission that will end on Wednesday, May 25, will be the last in a series of attempt, NASA said in a statement on Tuesday.

The robotic rover had last communicated on March 22, 2010. With inadequate energy to run its survival heaters, the rover likely experienced colder internal temperatures last year than in any of its prior six years on Mars. Many critical components and connections would have been susceptible to damage from the cold, NASA said.

The space agency said engineers' assessments have shown a very low probability for recovering communications with Spirit.

According to, Spirit's troubles began in April 2009, when it got stuck in a patch of Martian sand. Engineers worked for eight months attempting to free the rover, but to no avail. In its stationary position, Spirit's solar panels weren't able to tilt toward the sun and so it lost power during the winter of 2009 and 2010.

Dave Lavery, program executive for solar system exploration at NASA said the agency is transitioning assets to support the November launch of our next generation Mars rover, Curiosity. However, while we no longer believe there is a realistic probability of hearing from Spirit, the Deep Space Network may occasionally listen for any faint signals when the schedule permits.

Spirit, one of two rovers of NASA's Mars Exploration Rover Mission, landed on Mars on Jan. 3, 2004, for a mission designed to last three months. After accomplishing its prime-mission goals, Spirit worked to accomplish additional objectives. Its twin, Opportunity, continues active exploration of Mars, NASA said.