as they did back in 1998 and '99, mars polo lander, when they didn't get that signal back. those memories are seared in the collective consciousness at jpl. they've had great moments and they've had moments of absolute agony and defeat, as well. >> we want to avoid the agony and we would like a repeat of the high fives from "curiosity" in 2012. and rachel we, for people who a just tuning in and are like, why are they talking about mars and this "insight," what is the purpose of it all? >> there have been many missions to mars before. and to highlight how difficult this is, pulling off either landing a lander or a rover or an orbiter, bringing an orbiter to mars, more than half of the missions have actually failed. so there's about a 40% chance of success here. so, you know, this is incredibly difficult. space is hard. i just want to highlight that. but most missions to mars have been about studying the atmosphere or the surface. it hasn't really been about getting to the core, literally,