>The Mars rover Spirit is starting to show its age, and it's nearing the start of a long, cold winter. Now, its solar panels are covered with dust - compare the two images below:
>
>Clean: http://photojournal.jpl.nasa.gov/catalog/PIA03272
>Dusty: http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20071210a/JC4-Sol1355A_1358A_DeckPan_L456atc_br2.jpg
>
>Despite their extended time in a very harsh environment, both rovers continue to function. Kudos to the engineers and scientists involved for a job very well done.

The next model should have a feather duster... and then it'd last pretty much forever.

Really incredible. They were designed to last how long - couple of months?