You also need to think about the risk. The chances of a problem with newer technology may be small, but the impact of that risk (that you've gone all the way t

You also need to think about the risk. The chances of a problem with newer technology may be small, but the impact of that risk (that you've gone all the way to Mars and your camera doesn't work) is HUGE. Everything on that vehicle will have been reviewed, tested and retested and retested again all of which takes time. You don't just throw something new on there at the last minute and launch.