Defense Intelligence Reference Document Antigravity For Aerospace Applications

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I. Introduction
Gravity is the bane of aerospace transportation. The force of the Earth's gravitational
field acts to pull all objects, whether in motion or at rest, downward towards the Earth's
surface. Because aerospace transportation involves the motion of vehicles through the
atmosphere and/or into space, propulsion engineers are always faced with the
requirement that aerospace vehicles will have to carry enough propellant and
associated tankage in order to provide enough propulsive thrust to overcome the
downward pull of gravity and achieve rectilinear motion. Energy has to be expended by
a propulsion system to overcome the force of gravity in addition to providing for
rectilinear motion, and the majority of propulsive energy is dedicated to overcome
gravity. The aerospace propulsion engineer is faced with two choices for the control of
gravity in this regard: passive control and active control. Modern aerospace propulsion
technology, which is based on accumulated scientific knowledge since recorded history,
can only achieve the passive control of gravity whereby a given propulsion device must
develop a thrust that will passively counteract the Earth's gravitational pull, lift a
vehicle off the surface, and propel it through the air or into space. Newton's laws of
motion and gravity require that the fuel fraction of any aerospace vehicle can never be
less than that given by a simple function of the ratio of the vehicle's maximum speed to
the speed of its rocket plume, jet, fan, or propeller wake. For example, this limit implies
that a single-stage rocket that accelerates to escape velocity must be composed of
more than 93 percent fuel. That is because a rocket must accelerate its working fluid
from rest (relative to the rocket) up to its exhaust speed. Thus, exhaust speeds for
aircraft and chemical rockets are limited by material science, chemical reaction rates,
and engineering factors to only a few thousand meters per second.
To date, there is no technology that can achieve the active control of gravity. If one
could eliminate or otherwise control the Earth's gravity field, then one has the ability to
dramatically reduce the amount of propellant, its tankage, and the overall structural
size and mass of an aircraft or rocket because there will no longer be any need for
these to overcome the pull of Earth's gravity while transporting a payload across the
globe or into space. Instead, aerospace vehicles will only need to have the propellant
mass and infrastructure necessary to change their kinetic energy from rest to a final
velocity necessary to achieve atmospheric flight or space orbit. The Earth's gravitational
well will no longer have any impact on aircraft, launch vehicle, or spaceflight dynamics
if one were to achieve active gravity control. Aerospace vehicles would merely "levitate"
in air and their propulsion systems would be optimized for change-in-velocity missions.
However, it is possible to envision a form of active gravity control propulsion that would
not require a change in kinetic energy.
One of the primary concepts for the goal of affecting gravity is "antigravity," which is a
colloquial expression that specifically means the negation or repulsion of the force of
gravity. A more general term that encompasses this notion and other possibilities is
"gravity control."
If antigravity exists, it can be exploited to counteract or nullify the gravitational pull, or
attraction, of a planetary (or stellar) body that acts upon a much smaller body.
Einstein's General Theory of Relativity gives a prescription for a variety of different
antigravity generators. Even Newton's law of gravity offers several different classical
prescriptions. Newton's law of gravity can be used to simply nullify the gravity field of
one body acting on another body by using a clever arrangement of masses. The
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