" So why does JPL have this RFP website? "

You're kidding right?

The RFP website is to open offers for contracts to build stuff. In the case of MSL - it's to build a rig on which to test the final 20m or so of the sky-crane concept.

Whilst I have my doubts about skycrane - I dont see anything wrong, in principle, of using viking style deep-throttle motors to come to a hovering point ( nothing wrong or impossible with that at all ) - and then drop the lander down a cable to the ground. It's easy to look at the MER EDL animations based on the UHF MGS relayed data and go "woah - you wanna do that with a hovering thing?" - but obviosuly - most of the swinging in that system is due to the parachute and three points of mass in a line. Skycrane will be one point of mass until seconds before touchdown - and then only two points of mass. In principle, more stable than MER.

However - with all the experience and success out of JPL - I find it hard to see why you can be so 100% confident that it WILL WITHOUT DOUBT FAIL. Are you saying that you understand skycrane more than the people designing, simulating and testing it?

If MSL goes to mars with Sky Crane - it MIGHT auger in - in the same way Spirit and Opportunity might have augered in as well. But one things for sure - if MSL is going to mars - it's getting there via Skycrane and no other way.

So instead of dismissing the whole idea off hand - why not be constructive and explain, with facts, calculations and evidence, WHY, exactly, Skycrane will fail - and present this evidence to JPL to demonstrate that they're doing something wrong. If you're not prepared to do that - then why should we take your dismisal seriously?

Doug