MER-1 is actually the older sibling. For the most part I think she's a little bit better behaved. She's a better girl. She does what you expect her to do. You can count on her getting the job done.

MER-2 is the younger child, the younger sibling, who tends to be a little bit more spoiled sometimes. (P2K: MER-2 was actually launched first, now named "Spirit." MER-1 launched second, and is known as "Opportunity.") She's used to getting what she wants. An example: MER-2 had some problems, we had some parts that needed to be reworked, and what we ended up doing is going over and actually taking parts from MER-1 and putting in on MER-2, so that MER-2 can continue down the flow. MER-2 is going to be the first launch, so we had to get her ready. MER-2 tends to show problems more. Oftentimes it's because we're pathfinding with MER-2; we're integrating hardware that MER-1 hasn't done yet. So even though MER-1 was born first, she actually took her time in some of our system tests in a flight configuration, but not in a surface configuration. So I do think of MER-2 as the spoiled younger child.

On the human team that has been nurturing the robotic geologists:

I'm continuously amazed at how people step up to the plate when they have to. When we started ATLO we went out and recruited what we thought was a very good team, and to see the team mature, to see the team step up to the plate when we have problems, was truly amazing. You push 'em to the limit, and you don't think there's any possible solution to the problem that you just encountered. And you always realize there's just a little bit more you can give.