2015 3:03 (one minute excerpt above)
The Mars Rover Opportunity landed in 2004 and is still roaming the red planet eleven years after it's expected demise. It's up there looking for ancient lakes, and rivers, and signs of life. It recently had it's flash memory reformatted.
Photos are courtesy of JPL all other credits: Laura Heit
The sound is Mars Rover field recordings of solar wind. The amplitude changes as it crawls in and out of valleys and craters.