P2K: What's the hardest thing about the Mars Exploration Rovers mission compared to other missions?

John Wirth: That’s the easiest question to answer because the answer is simple: two spacecraft. At first, everybody said, two spacecraft, that’s easy to do because you run a procedure on one, and you do the same exact thing again on two, but it doesn’t work out that way. With two spacecraft, there’s no dead time. Sometimes on one spacecraft - this is experience talking - you get some slow time, such as "thermal vac" (Ed: thermal vacuum testing) which is just a real quiet time, and you’re just sitting at the console and doing nothing. But with two spacecraft, there’s no dead time. If one is being worked on somewhere you can’t touch it, but the other is available to be touched, so two spacecraft is, if you don’t mind me saying it, a real "challenge" (Ed: synonym for extremely difficult task!)

P2K: What's the most exciting thing you have to do on this project? The most challenging?

John Wirth: The excitement is the rush of all the work. It’s exciting just because constantly there is no dry spell. You know, some jobs you actually get a dry spell and your sort of get bored a little bit, and you start thinking of stuff to do. But this project and this job, it’s just constant activity, so it sort of gives you a little rush because you get something new each day, and you got something to think about and something’s challenging you. It’s like always putting together a complicated puzzle: every day you've got to figure out another piece of the puzzle ...We’ve been finding a lot of problems here at the Cape that we didn’t expect. We expected a quieter time, so it’s been two years later, it’s 2 1/2 years later, it’s definitely worn me out a little bit. I’m a lot skinnier and I had more hair back then too.