End of Spirit

In the wee hours of May 25, 2011 the scientists and engineers of the Mars Exploration Rover team sent the last command in attempt to contact the Spirit rover. Over the past year, they have sent over 1,200 commands and haven’t heard anything in reply from the stuck and likely frozen rover.

Spirit, the plucky rover that landed on Mars on January 3, 2004, overcame many difficulties and endured way past her 90-day warranty. For nearly six years, she traveled long distances, climbed hills — something the rovers weren’t really designed to do — she roved and stopped at interesting rocks along the way, all the while beaming back the information she garnered, enlightening us all about the nature of Mars, past and present.

Spirit trapped in soft Martian soil in May of 2009 and that was the beginning of the end. The Mars Exploration Team spent months planning for her extrication, and then months again attempting to drive her out, but they ran out of time and power in the approaching Martian winter. The team was unable to put the rover in a favorable position to catch rays of sunlight on her solar panels, and after another freezing, grueling winter, Spirit has now likely succumbed to the harsh environment on Mars.

One of the challenges that Spirit faced is that it always had dust on the solar arrays, Callas said, even during the first winter on the Columbia Hills. After a timely dust cleaning event by a dust devil, the team was able tilt Spirit to gather sunshine and she survived. The second winter she achieved a 10% tilt and survived; the third winter, the team was able to find a 30% tilt – again she survived. But the 4th winter, there just wasn’t the right geography in the sand pits of Troy that would enable Spirit to survive after it became embedded.

Spirit made many discoveries – finding carbonates which told scientists much about the past habitability of Mars and that it likely had a thicker atmosphere at one point. Then, even failure brought discovery, as the malfunction of the right front wheel in 2004 meant the team had to relearn to drive the rover, driving it backwards, dragging the wheel behind. This churned up the top soil and revealed what was under the surface: amorphous silica, which is evidence for an ancient hydrothermal system on Mars, which means not only water but an energy source that could have been driving a type of ecosystem in one particular location on Mars.

Spirit roved her way into our hearts and into the science books. She will not be forgotten. I’m sure we’ll be telling stories of when Spirit was a wee little rover.

The last command was sent early on May 25, 0700 UTC, it was just after midnight at JPL in Pasadena, California