Lookout NASA, you have Rover competition. And it uses the amazing Rotacaster Omni-wheels for unsurpassed manoeuvrability in confined spaces. There is no need of a steering mechanism to turn the Rotacaster Rover thanks to the unique wheel design.
About this creation
NASA Mars Spirit Rover
I've had a few attempts, going back to the days of my LEGO Mindstorms RCX Kit to build a working Mars Rover that had the same suspension system. They all failed for various reasons, including steering the front and rear powered wheels. Also I was probably making the whole drive-train far too complicated, which introduced lots of reliability issues.
The Mars Rotacaster Rover
I've been meaning to have another go at a 'Spirit' or 'Opportunity' type Rover, but it just hasn't happened until another one of my sleepless night with a brain that was permanently stuck in gear, which took place tonight. And before I really new it, I had started on a Rover, the drive and suspension fell into place as I lay on the pillow. That was it, I wasn't going to be catching any 'ZZZZZ's' tonight!
Test Driving the Mars Rotacaster Rover
This version is a proof of concept version, using 6x Rotacaster Omni-wheels with each corner wheel driven via a small LEGO Power Functions Motor. The Left and Right Motors are paralleled together and connected to the NXT Motor Ports via a pair of Power Functions adapter cables. Each motor is direct driven, and despite their size, the Power Function Motors do the job very well. To well for me to control properly....
As can be seen from the video, the concept works brilliantly. Having the ability to turn in its own length without the need for normal mechanical steering can only be achieved, thanks to the unique design of the Rotacaster Omni-wheels.