This image from the Navigation Camera on NASA's Curiosity Mars rover shows wheel tracks printed by the rover as it drove on the sandy floor of a lowland called "Hidden Valley" on the route toward Mount Sharp. (NASA/JPL)

It's been two years since NASA's latest roving laboratory touched down in the Gale Crater of Mars. Its many, many parents are presumably as proud as they were when it first landed:

After celebrating last year's anniversary with a selfie, Curiosity has chosen a dramatic monochrome shot of its tracks in the soil for year two. A transition from tween vanity to teen dramatics, perhaps?

The rover was initially intended for a two-year mission, but that was extended indefinitely back in December 2012. Now, NASA scientists expect Curiosity to still be chugging along and doing science when the next rover lands in 2020. The rover has accomplished a lot in the past two years, including helping NASA scientists prepare for future human missions to Mars.

Not to steal Curiosity's thunder, but it's worth remembering that the Opportunity Rover, which was designed for a 90-day, single kilometer mission, is still going more than 10 years later. Its partner, Spirit, is no longer functional. There's a Web comic about it, and it'll make you cry.

But Curiosity is built of even tougher stuff. And luckily, the beloved Mars Curiosity parody account on Twitter hasn't slowed down, either.

The Mars 2020 rover will riff on Curiosity's top-notch design, but with a few tweaks. For starters, new wheels: Curiosity's wheels haven't stood up well to some of the Martian terrain the rover has encountered, so NASA engineers are working on a new design.

And while Curiosity does most of its own analysis on-board, the 2020 rover will  use its equipment to select the best samples for study back on earth. When humans do make it to Mars, the 2020 payload will be waiting to help us understand the planet's past.

But until then, Curiosity is our top rover in residence.