Larger Still!

The same lift x7 in a three stage system similar to the one shown here

http://www.scribd.com/doc/30943696/ETDHLRLV

Only 7.751x larger in all dimensions and 59.5x heavier!

By doubling the number of combustors at every position, we have 36
doublets to obtain the same 72 combustors as pairs of combustors
around a ring that's only 99 ft in diameter. This lifts an external
tank looking hydrogen oxygen tank pair that's 108 ft in diameter and
600 ft tall - massing 100,000,000 lbs - with 144,000,000 lbf engine
beneath it. A single SSTO lifts 7,500,000 lbs into orbit. Seven of
these large elements lift 91,600,000 lbs into orbit!

Applied to power satellites this larger system allows a 25 mile
diameter collector to be launched capable of producing 595,000 MW of
power at GEO beaming power from a 3,300 ft diameter emitter to mobile
users on the ground. The Rayleigh Criterion means larger optics on
orbit allow smaller optics on Earth.

Alternatively a satellite pair can be launched consisting of emitter
hardware only that's 2.3 miles across and when one is operating at GEO
and the other operating 2.2 million miles from the Sun beaming energy
to the first one - the pair produces for nearly the same cost as the
concentrator based system over 14,000,000 MW of laser energy -
reducing energy costs further.

Only two pairs of satellites this size are enough to supply all our
energy needs today.

One of these operating a laser light sail can generate 22,000 lbf of
thrust from an efficient mirror! Lifting a 66,000 lb payload at 1/3
gee for 1 year gets it up to 1/3 light speed. Applying the same light
to light sails in the asteroid belt retrieves 170,000 tons per year
without any expenditure of propellant.

A similar satellite orbiting a target star slows the same payload in 1
year and reorganizes that star system at the same rate.

A sail 2200 square feet produces 'lift' of 10 lbs per square foot is
large enough to provide the thrust needed for the missions just
described. Light intensity is 6,360 MW per square foot. A light sail
that is 99.999999% reflective (which have been built) absorbs only 64
Watts per square foot. Radiating this across both sides of the film
32 Watts/sq ft is radiated away in vacuum - which raises the
temperature to a little less than the boiling point of water!

One satellite retrieves 170,000 tons per year from the asteroids.
One satellite dispatches 11 tons per year to nearby stars.