This is a series,

this CBS I in the world.

I'm John Bachelor. Bob Zimmerman is here to take us to curiosity

on the surface of the planet Mars.

Bob has watched this story for years.

There's a wheel on curiosity

that now and again needs to be examined closely.

Bob's got it up on behind the black. What do you see Bob?

Yeah, I want to be clear on this. It's not just one wheel.

All of curiosity's wheels have aware problems.

This is something they discovered only about two or three years into the mission,

that the design of the wheels, and this is engineering, you don't know what you're going to get, you try to make a design and you think will be best,

but they discovered that the wheels of curiosity

were wearing out quicker than expected. This is like two years into the mission. Now we're about a dozen years into the mission.

What they did is they changed how they moved the rover and

the software how the rover worked to better protect the wheels and that has worked

over the years, but it does require that after Curiosity has moved about once every

kilometer, they do a wheel survey. They take pictures of the wheels using a

high close-up camera that's at the end of the robot arm and they take survey

pictures they take pictures of the wheels and they move curiosity a few feet so

that the wheels rotate and they take more pictures and they do this periodically and it never gets

any coverage from anybody but me I see the pictures when they show up and I

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