The 1975 Stanford Torus (shown opposite) was engineered with a 1 inch thick aluminum pressure hull to hold air at 1 atmosphere pressure and house a population of 10,000. The Stanford Torus was conceived to be built using materials launched from large infrastructure built on the lunar surface, and would have had a mass when completed of about 100 million tons with only partial shielding coverage against ionizing radiation.

A tensegrity engineered UHMWPE pressure hull of the same dimensions and pressure capability has a mass only 6% of the aluminum hull, or 17 times less. The Skyframe habitat's initial deployment would require perhaps 2 to 3 ground launches and 3500 tons of water shielding to give full coverage to 1 meter depth, sufficient for 6 month stay time, scalable as required for longer stay times.

The iconic O'Neill Cylinder image (at right) published shortly after the Stanford study depicts a colony 20 miles long and 5 miles across. Despite its wide currency the design has numerous design flaws. The 20 mile long narrow co-rotating adjustable angle mirrors would have been subject to very large g-forces. Long cylinders are rotationally unstable. Half of the cylinder wall was to be transparent, and it is doubtful at best that the 5 miles of air could provide enough shielding. The economic model was for the cost of construction to be paid for by the labor of the colonists in constructing space solar power collectors for the transmission of microwave beamed energy to earth. This is obviously a high risk scenario involving very large capital outlay paid back over a very long timeframe with a large uncertainty of outcome.

By contrast Skyframe's habitat requires comparatively very modest investment to start at a modest scale and achieves scale through growth paid for by operational profits on a pay-as-you-go basis.

The International Space Station (at right) required 40 launches for its assembly, has a mass of 400 tons, and provides a pressurized volume of 913cu.m.

A Skyframe tensegrity torus pressure hull of 10m major radius and 5m minor radius would have a volume of 5000 cu.m and and mass of 1.6 tons.

Obviously not all the comparisons are exactly equivalent, but the superior mass efficiency of Skyframe's approach to the problem is clear. In addition to this Skyframe's habitat rotates to provide gravity effect, offers customizable levels of water shielding, beginning at 1m depth, and provides somewhat earth-like living conditions in deep space -- the clincher being its capacity for an extended cycle of growth events, to a minimum two orders of magnitude in linear dimension.

Habitable real estate for the human future in space