Here is some of the background information I've collected relating to tri-star wheeled vehicles.

This Article on the Land Master is from the March 1977 issue of Popular Science

Title and Images
Text

The US patent for an Amphibious Star Wheeled Vehicle

patent text - page 1
patent text - page 2
patent figures 1,4, and 5
patent figures 2, and 3
patent figure 6

This information on the Lockheed Terrastar is from Fred W. Crismon's book :
U.S. Military Wheeled Vehicles
ISBN: 0-912612-21-5
Published by Crestline Publishing Co. Inc. in 1983

Another terrastar image.

Here are several images of the Land Master from the movie Damnation Alley.

Some select pages from Martin Bradley Weinstein's book:
Android Design
Practical Approaches for Robot Builders
ISBN: 0-8104-5192-1
Published by Hayden Books in 1981

My Tri-Star Wheel Design Info

(lots of LEGO Technic stuff to add here as soon as I get my notes together)

A tri-star wheel design that uses a planetary differential built into the wheel assembly.

Design description and color key
2D image of this design