The technology described in this post has not been tested, but
it looks trivial when compared to rocket launchers, and it
may reduce the cost of space access to a few dollars per kilogram!

The technology is based on GPS, a reusable sounding rocket,
cheap terrestrial bolo, cheap lunar rotovator, cheap cargo
sacks, and a small Zylon sling. The bolo and the rotovator
are useful terms defined by Robert Forward. They are described
he http://www.islandone.org/LEOBiblio/SPBI122.HTM
(Robert P. Hoyt calls lunar rotovator "lunavator.")
The rotovator hurls the sacks filled with regolith (Moon dust)
towards the Earth. It is mounted on a rotating arm which is
attached to a large, rotating, toroidal greenhouse. The arm
rotates independently of the greenhouse, so it can easily
change the angular velocity of the rotovator. The maximum
length of the rotovator is about 200 km. When a winch reels
its cargo in, the cargo moves faster to conserve its angular
momentum. This fact makes it possible to increase the orbital
energy of the rotovator and the greenhouse without the need
for any external thrust. It is as simple as capturing
the cargo, reeling it in, and releasing it. The orbital
velocity of the rotovator is only 1.6 km/s, much less than
the Moon's escape velocity (2.4 km/s). When the cargo is
released from the rotovator, its velocity relative to the
Moon is 3.2 km/s. It is gradually slowed down by the lunar
gravity to 0.8 km/s (3.2 km/s - 2.4 km/s = 0.8 km/s).
Gravitational pull of the Earth accelerates the cargo by
11.2 km/s, which is the Earth's escape velocity. When the
cargo is captured by the terrestrial bolo, its velocity
relative to the bolo is 4.3 km/s. (The cargo gains 3.5 km/s,
which is the difference between the Earth's escape velocity,
and the orbital velocity of the bolo, which is 7.7 km/s).
The bolo is larger than the rotovator, but it has the same
design, and is mounted on a rotating arm, which is attached
to a large, rotating, toroidal greenhouse. The bolo
reverses velocity of the cargo and drops it on the Earth.
This maneuver increases the orbital energy of the bolo and
the orbital energy of the greenhouse which is attached to the
bolo. When the cargo is released from the bolo, its velocity
relative to the Earth is only 3.4 km/s. Before the cargo
enters the atmosphere, it is captured at the altitude of
100 km by a sling attached to a payload which was launched
from the Earth a few minutes earlier. The payload has the
same mass as the cargo. Its velocity relative to the Earth
is only 2.5 km/s. The sling is made of Zylon, makes up 20%
of the payload's mass, and is strong enough to reverse
relative velocity of the cargo and the payload. When the
cargo and the payload separate, cargo velocity relative
to the Earth is reduced to 1.6 km/s, and payload velocity
relative to the Earth is increased to 4.3 km/s. Finally, the
payload is captured by the bolo. If the payload is going to
be used in the greenhouse orbiting the Earth, the bolo's
winch reels it in. If it is going to be used in the
greenhouse orbiting the Moon, The bolo reverses payload's
velocity and hurls it toward the rotovator, which captures
it.

The rotovator and the bolo do not have to be made of
unobtanium, buckytubes, or even Zylon. Carbon fibers and
S-glass fibers are strong enough, and they are immune to the
radiation and temperature extremes of the outer space. Perhaps
the most practical material for the rotovator and the bolo is
a composite made of carbon fibers and S-glass fibers fused
together under high pressure and high temperature. More info
about slings: http://www.islandone.org/LEOBiblio/SPBI1SL.HTM

It is easy to design a reusable sounding rocket which lifts
the payload to the altitude of 100 km and accelerates it to the
velocity of 2.5 km/s. (When the payload separates from the
rocket, its total energy is equivalent to the kinetic energy
of only 3 km/s.)

Modern GPS technology guarantees high precision of the maneuvers:
http://gipsy.jpl.nasa.gov/igdg/syste....html#accuracy