Mars exploration: NASA bids Spirit adieu

With space shuttle Endeavour crew wrapping up a historic mission, including final assembly of the International Space Station, NASA also announced it had ended operational planning activities for the Mars rover Spirit and that it had converted the Mars Exploration Rover Project into a single-rover operation focused on rover Spirit's still-active twin, Opportunity.

After six years driving around on the surface of Mars, robotic rover Spirit finally succumbed to the harsh conditions of the Red Planet.  Spirit outperformed its three month mission, making it last six years, and instead of travelling a few hundred metres, as designed, it traversed 7.7 kilometres across the Martian surface, including up and over a mountain.

Finally, the rover landed in soft sand and got stuck axle-deep. All manoeuvres to get it out were unsuccessful and its tilt on the slope ensured that its solar panels were tilted away from the sun. Unable to recharge its batteries, it basically froze in the cold Martian winter.

It finally died a mechanical death, unresponsive to all commands dispatched by NASA centre on Earth. Spirit last communicated on March 22, 2010, as Martian winter approached and the rover's solar-energy supply declined.

The rover operated for more than six years after landing in January 2004 on what was planned as a three-month mission.  A series of re-contact attempts, designed for various possible combinations of recoverable conditions, finally ended 27 May.

"Our job was to wear these rovers out exploring, to leave no unutilized capability on the surface of Mars, and for Spirit, we have done that," said Mars Exploration Rover project manager John Callas of NASA's Jet Propulsion Laboratory (JPL).