The first time I heard about the "sky crane" was at a small JPL sponsored seminar concerning MarsGram. An engineer stood up and told us about the "sky crane". I was so struck with how utterly stupid this idea was that I blurted out my opinion without thinking about it. It turned out the engineer who was doing the talking was the sky crane's designer (yet another example of me putting my foot in my mouth). I just clammed up after that and said no more. I still think it's an incredibly stupid idea and can't believe it was not instantly dismissed. Simply landing a 3-axis stable vehicle on a rocket is a very difficult control problem. Mars makes it more difficult because the dust being blown up is radar reflective (lots of iron in it). The sky crane has all the problems of a conventional lander, plus the issues of a compound pendulum, plus the issues of the payload interacting with the rocket plume, plus the issues of the Martian wind interacting with the whole assembly, .... need I go on?

PB mentioned that this was for the Mars Science Laboratory (MSR). "MSR" formerly stood for "Mars Smart Lander". The engineers realized that making a Mars Smart Lander was going to be too expensive so they opted to make it a Mars Dumb Lander (Payload hanging from a rope!?). However changing the MSR name had become an embarrassment (MSR was previously called "Mars 2009" after being called "Mars 2007" after being called "Mars 2005"). So the "MSR" acronym became Mars Science Laboratory. Cute, isn't it?

Gary