Spirit – The Solar Rover That Lasted 20 Times Longer Than Planned

We already have Opportunity on our site, so it is time to give its twin the attention it deserves. Spirit (officially MER-A) landed in Gusev crater on Mars on 4 January 2004, three weeks before Opportunity touched down on the other side of the planet. Its name came from a NASA essay competition for students.

Both rovers were solar-powered six-wheelers designed for a mission of just 90 sols, about 92 Earth days. Each wheel had its own motor. The rover was steered at the front and rear and could handle slopes of up to 30 degrees. Its top speed was 5 cm per second; the average was closer to 1 cm per second. The solar arrays delivered roughly 140 W at the start of the mission. NASA expected Martian dust to cover the panels and end the mission within months.

Then Mars surprised everyone: wind gusts and dust devils cleaned the panels again and again, restoring power. Spirit kept working twenty times longer than planned and drove 7.73 km instead of the planned 600 m, studying rocks that showed that water had once played a role in Gusev crater. Even after one wheel stopped turning in 2006, the team drove it backwards, dragging the broken wheel, which by accident dug up important minerals.

In late 2009 Spirit got stuck in a sand trap, at an angle that kept its panels from catching enough winter sun. Its last signal reached Earth on 22 March 2010, and NASA ended the mission on 25 May 2011. Spirit shows something every solar traveller knows: the angle of your panels and clean surfaces matter. Its little successor in the sky was the Ingenuity helicopter.

Technical data

Photos

• Top photo: NASA/JPL / Wikimedia Commons, Public domain
• Spirit seen from above: a mosaic of its own solar deck, take… Photo: NASA/JPL-Caltech/Cornell / Wikimedia Commons, Public domain
• Final checks of Spirit's solar arrays at Kennedy Space Cente… Photo: NASA / Wikimedia Commons, Public domain

Sources

• Wikipedia: Spirit (rover)
• NASA: Mars Exploration Rovers