NASA Technical Memorandum 107289

6'

The Challenge to Create the Space Drive

Marc G. Millis

Lewis Research Center

Cleveland, Ohio

Prepared for the

Interstellar Flight Symposium of the 15th Annual International Space

Development Conference

sponsored by the National Space Society

New York, New York, May 23-24, 1996

National Aeronautics and

Space Administration

Jul 16, 1996

THE CHALLENGE TO CREATE THE SPACE DRIVE

BY MARC G. MILLIS

Space Propulsion Tech. Div., NASA Lewis Research Center, 21000 Brookpark Rd., Cleveland, OH 44135, USA

To travel to our neighboring stars as practically as envisioned by science fiction, breakthroughs in science are required.

One of these breakthroughs is to discover a self-contained means of propulsion that requires no propellanL To chart a

path toward such a discovery, seven hypothetical space drives are presented to illustrate the specific unsolved challenges

and associated research objectives toward this ambition. One research objective is to discover a means to asynunetrically

interact with the electromagnetic fluctuations of the vacuum. Another is to develop a physics that describesinertia,

gravity, or the properties of spacetime as a function of electromagnetics that leads to using electromagnetic technology

for inducing propulsive forces. Another is to determine ff negative mass exists or ff its properties can be synthesized.

An alternative approach that covers the possibility that negative mass might not exist is to develop a formalism of

Mach's Principle or reformulate ether concepts to lay a foundation for addressing reaction forces and conservation of

momentum with space drives.

1 . INTRODUCTION

New theories have emerged suggesting that gravitational and

inertial forces are caused by interactions with the

electromagnetic fluctuations of the vacuum [1, 2]. There have

also been studies suggesting experimental tests for massaltering affects [3], and a theory suggesting a "warp drive" [4].

With the emergence of such new possibilities, it may be time

to revisit the notion of creating the visionary "space drive."

Space drive, as defined here, is an idealized form of propulsion

where the fundamental properties of matter and spacetime are

used to create propulsive forces anywhere in space without

having to carry and expel a reaction mass. Such an

achievement would revolutionize space travel as it would

circumvent the present constraint of requiring propellanL

Without such a discovery, human interstellar exploration may

not be possible [5].

One of the missing prerequisites to achieving this

breakthrough is having a starting point for the research; a

description of the specific problems to be solved. Without

this fh-ststep of the Scientific Method there is no framework

against which to assess, augment, and apply emerging science

to the goal of creating a space drive.

To provide such a starting point, a variety of hypothetical

space drives are presented and analyzed to identify the specific

problems that have to be solved to make such schemes

plausible.

2. PROBLEM FORMULATION METHOD

A NASA precedent for systematically seeking revolutionary

capabilities is the "Horizon Mission Methodology" [6]. This

method forces paradigm shifts beyond extrapolations of

existing technologies by using impossible hypothetical

mission goals to solicit new solutions. By setting

impossible goals, the common practice of limiting visions to

extrapolations of existing solutions is prevented. This

method forces one to look beyond existing methods and

specify the technologies and sciences that are genuinely needed

to solve the problem, whether the solutions exist yet or not

The theme of the Horizon Mission Methodology is

followed here. The "impossible" goal targeted in this exercise

is to create a space drive. In the spirit of the Horizon

Methodology, the envisioned propulsion methods can

entertain the possibility of physics yet to be discovered.

However, to ensure that the envisioned methods are consistent

with fLrmly established physics, the analysis imposes the

constraints of conservation of momentum and energy, and

requires that observed natural phenomena are not contradicted.

From imposing these constraints, the characteristicsneededto

make space drives plausible can be identified.

Seven different hypothetical propulsion concepts were

created for this exercise. These concepts were envisioned by

considering analogies to collision forces and interactions with

fields to produce net forces.

3. HYPOTHETICAL COLLISION SAILS

One means to produce force is collisions. Conventional

rocket propulsion is fundamentally based on the collisions

between the propellant and the rocket These collisions thrust

the rocket in one direction and the propellant in the other.

To entertain the analogy of collision forces for a space

drive, consider the supposition that space contains a

background of some form of isotropic media that is constandy

impinging on all sides of a vehicle. This media could be a

collection of randomly moving particles or electromagnetic

waves, either of which possess momentum. If the collisions

on the front of a vehicle could be lessened and/or the

collisions on the back enhanced, a net propulsive force would

resulL Three variations of such a hypothetical collision-sail

are illustrated in figures 1 through 3. In all these
Marc G. MiUis

illuswations, the rectangle represents a cross sectional dement

of the sail and the wavy lines represent impinging waves of

the isou-opic radiative media. The large arrow indicates the

direction of acceleration.

Fig. 1 Hypothetical Differential Sail

Analogous to the principles of an ideal radiometer vane, a net

difference in radiation pressure exists across the reflecting and

absorbing sides.

Fig. 2 Hypotheti_ Diode Sail

Analogous to a diode or one-way mirror, space radiation

passes through one direction and reflects from the other

creating a net differeuce in radiation pressure.

Fig. 3 Hypothetical Induction Sail

Analogous to creating a pressure gradient in a fluid, the energy

density of the impinging radiation is raised behind the sail and

lowered in front of the sail to create a net difference in

radiation pressure across the saiL

For any of these concepts to work, there must be a real

background media in space. This media must have a

sufficiently large energy or mass density, must exist equally

and isotropicaUy across all space, and there must be a

controllable means to alter the collisions with this media to

propel the vehicle. A high energy o_ mass density is required

to provide sufficient radiation pressure or reaction momentum

within a reasonable sail area. The requirement that the media

exist equally and isotropically across all space is to ensure that

the propulsion device will w_ anywhere and in any direction

in space. The requirement that there must be a conm3Uable

means to alter the collisions ensures that a controllable

propulsive effect can be created.

The supposition that space contains isotropic media is

reasonable. Space contains eleclmmagnetic fluctuations of the

vacuum, also called the Zero Point Fluctuations CZPF), [7]

Cosmic Background Radiation (CBR) [8], free hydrogen

(protons) [9],the theoretically suggestedvirtualpairs[I0]and

possiblyevendarkmatter[11].Whetherany ofthesemedia

hasallthecharacteristics needed to be used as a propulsive

media remains a subject for fulure research.

Regarding conse_ation of momentum, this condition can

be satisfied by using the media as the reaction mass. Any net

momentum imparted to the vehicle must be equal and

opposite to the momentum change imparted to the media.

Regarding conservation of energy, this condition can be

satisfted by imposing the consWaint that whatever propulsive

method or phenomena is used, the total system energy before

and after the propulsive effect is equal. This includes the

energy state of the surrounding media, the energy state of any

energy sources on the vehicle, the kinetic energy imparted to

the vehicle, and any loss mechanisms.

4. HYPOTHETICAL FIELD DRIVES

In addition to producing forces with collisions, forces can

be produced from interactions between matter and fields.

Gravitational fields accelerate masses and electric fields

accelerate charges. To entertain the analogy of using field

interactions to create a space drive, it is necessary to assume

that there is some way for a vehicle to induce a field around

itself that will in turn accelerate itself. Field drive concepts

are more complex and more speculative than collision sail

drives. A description of the critical issues follows.

Even ff there was a way for a device on a vehicle to

induce force-producing field, there is still the question of

whether such a field would accelerate the vehicle. A typical

expectation is that the induced forces would just act between

the vehicle's field-inducing device and the rest of the vehicle,

like blowing in your own sails, or trying to move a car by

pushing on it from the inside. In such cases all the forces act

internally and there would be no net motion of the vehicle.

For reference, this issue can be called the "net external force

reClUL, emenL"

The net external force requirement is closely related to

conservation of momentum. Conservation of momentum

requires that the momentum imparted to the vehicle must be
The Challenge to Create the Space Drive

equal and opposite to the momentum imparted to a reaction

mass. In the case of a field drive, there is no ob_ous reaction

mass for the vehicle to push against.

Similarly to conservation of momentum is the issue of

conservation of energy. This issue can be satisfied by

imposing the constraint that whatever propulsive method or

phenomena is used, the energy required to create the effect is

equal to the kinetic energy imparted to the vehicle and to

whatever constitutes its reaction mass, plus any inefficiency

losses. In addition, there is also the issue of conlzollability,

insuring that the force-producing effect can be turned on and

offat will.

A closely related aspect to controllability is

sustainability. Sustainability refers to the ability to continue

the propulsive effect throughout the vehicle's motion. This

implies that the force inducing effect must work in both an

inertial flame and an accelerated frame. It also requires that the

force-producing field is carried along with or propagated with

the vehicle, or at least can be induced again after the vehicle

has been set in motion.

In the spirit of the "Horizon Methodology", it is assumed

a priori that space drives are possible. By doing so and then

by addressing the critical issues, the required physical

characteristics of matter and space to make such propulsion

methods plausible can be identified. Future research could

then determine whether these conditions can be created with

the phenomena that are known to exist, or at least indicate

what other phenomena to search for.

Four hypothetical field drives, "Diametric Drive," "Pitch

Drive," "Bias Drive," and "Disjunction Drive," are presented

next and illustrated in figures 4 through 7. These concepts

were envisioned by examining the characteristics that describe

a field or how matter reacts to a field, and then assuming it is

possibletomodifya givencharacteristic ofthisrelation.The

DiametricDriveworks with fieldsources,thePitchDrive

with the field itself, the Bias Drive with the properties of the

space that contain the field, and the Disjunction Drive with

the properties ofmatterthatcreateandreactto a field.

A common theme to all of these is that an asymme_/c

field is induced such that a gradient is located at the center of

the vehicle, or more specifically at the center of whatever part

of the vehicle will experience a reaction force from the field.

An asymmetric field is required so that a net force is created on

the vehicle.

These concepts are presented in the context of using mass

and gravitational properties. A more thorough treatise would

also have to address using space media and electromagnetic

phenomena.

4.1 Diametric Drive

This irtrsttype of hypotheticalfieldpropulsion,as

illustrated infigure4,considersthepossibility ofcreatinga

local gradient by the juxtaposition of diametrically opposed

field sources across the vehicle. This is analogous to negative

masspropulsionandtocreatinga pressuresourceandsinkin

a space media as suggested previously with the Induction Sail.

Fig. 4 Hypothetical DiamcU-ic Drive

It is theoretically possible to cream a continuously

propulsive effect by the juxtaposition of negative and positive

mass as suggested by Bondi [12], Winterberg [13] and Forward

[14]. A crucial assumption to the success of this concept is

that negative mass has negative inertia.

Mathematically, this concept can be illustrated by the

following equation:

V,y,=(-m) (_o) 4(x+d)2+y 2 +(+m)4(x_d)2+y (_o) 2 where

Vsys is the gravitational scalar potential for the combined

system, shown as a surface plot over an x-y plane in figure 4

(singularities have been truncated for clarity). The first term

is the gravitational potential for the negative mass, -m, the

second for the positive mass. +m. In both cases, G is

Newton's gravitational constant. The negative mass is located

a distance, d, along the x axis behind the origin and the

positive mass is located a distance, d, in front of the origin.

The origin is taken to be the midpoint between the two

masses along the x axis.

By taking the gradient of the scalar potential caused by

the negative mass at the location of the positive mass, and of

the positive mass at the location of the negative mass, the

_.elerations for each mass can he calculated;

-G(-m ) (2a)

a_.=

for the negative mass which is in the positive x direction, and

G (+ m ) (2b)

a+.- (2d)_

forthepositivemass whichisalsointhepositivex direction.
Marc G. MiUis

Their combined interucfions result in a sustained acceleration

of both masses in the same direction.

4.2 Pitch Drive

This second type of hypothetical field mechanism, as

illustrated in figure 5, entertains the poss_ility that somehow

a localized slope in scalar potential is induced across the

vehicle which _ forces on the vehicle. In contrast to the

diameffic drive presented earlier, it is assumed that such a

slope can be created without the presence of a pair of point

sources. It is not yet known if and how such an effect can be

created.

Fig. 5 Hypothetical Pitch Drive

Mathematically, this can be illustrated by the following

equatio_

(3)

where Vsys is the gravitational scalar potential for the

combined system, shown as a surface plot over an x-y plane

in figure 5, which is equal to the superposition of the

potentials from the vehicle and the induced pitch effect. The

term for the vehicle's gravitational potential is the familiar

Newton's gravitational potential where r is the distance from

the source mass (r2 = x2 + y2 fox the x-y plane). The origin

is taken to be at the center of the vehicle. To entertain the

poss_illty of a Pitch Drive, a localized gradient in the scalar

gravitational potential is superimposed across the symmetric

gravitational potential already present from the vehicle's mass.

This induced pitch effect is represented by a magnitude, A

(units of acceleration), with a negative slope in the positive x

direction, and is localized by a Gaussian distribution, e-r2,

over the distance, r, centered at the origin. This localizing

equation was arbitrarily chosen for illustration purposes only.

By taking the gradient of the scalar potential at the

location of the vehicle (r=0), the acceleration fox the vehicle is

determined to be equal to A, the magnitude of the induced

effect, and acts in the positive x direction.

4.3 Bias Drive

The third type of hypothetical field mechanism as

illustrated in figure 6, entertains the possibility that the

vehicle alters the properties of space itself, such as the

gravitational constant, G, to create a local propulsive gradient.

From this asymmetric alteration of a space property a local

gradient similar to the Pitch Drive mechanism results.

Figure 6 is drawn showing the result of modifying

Newton's gravitational constant, G, around the vehicle's own

mass. Newton's constant has been modified to have a

localized bias where it is reduced behind the vehicle and

increased in f_vnt.

Fig. 6 Hypothetical Bias Drive

Mathematically, this concept can be illustrated by the

following equation:

(4)

where V is the gravitational scalar potential plotted over an xy plane, shown as a surface plot in Figure 6. This scalar

potential is described by the familiar Newton's gravitational

potential on the right which is multiplied by a spatially

asymmetric modifier on the left. The spatially asymmetric

modifier is represented by a magnitude, B (units of mass over

distance squared), multiplied by x, to give a positive slope in

the positive x direction, and is localized by a Gaussian

distribution as with the Pitch Drive. The "+l" identity term

is necessary to return the Newtonian gravitational potential to

its original form at large distances (r>>0).

4
By taking the gradient of the scalar potential at the

location of the vehicle (r--0), the acceleration for the vehicle is

determined to be equalto BG, the productof the magnitudeof

the induced effect and Newton's constant, and acts in the

positive x direction.

A similar concept by Alcubierre [4] suggests creating a

propulsive effect by asymmetrically altering spacetime itself.

Alcubierre theorized that by using large quantities of negative

energy density with an equally large positive energy density,

faster-than-light travel would be possible without violating

general relativity. The negative energy density expands

spacetime behind the vehicle and the positive energy density

contracts spacetime in front of the vehicle. The net effect is

that this "'warped" space and the region within it would propel

itself "with an arbitrarily large speed." Observers outside this

"warp" would see it move faster than the speed of fight.

Observers in,de this "'warp" would feel no acceleration as they

move at warp speed. Although a sub-light-speed space drive

would constitute a sufficiently important breakthrough, the

possibility that a space drive may also enable faster-than-light

transport is intriguing. The feasibility of this "warp drive"

theory is an open issue.

4.4 Disjunction Drive

The fourth type of hypothetical field drive, as illustrated

in figure 7, entertains the possibility that the source of a field

and that which reacts to a field can be separated. By displacing

them in space, the reactant is shifted to a point where the field

has a slope, thus producing reaction forces between the source

and the reactant. It is assumed that the source and reactant are

held apart by some sort of rigid device.

Fig. 7 "Disjunction Drive"

The ChallengetoCreatethe Space Drive

Obviously, a critical issue of this scheme is whether the

field's source is a separate entity from that which reacts to a

field. This perspective is similar to that used in the analysis

of the properties of negative mass [14]. In the course of

examining the nature of hypothesized negative mass, three

different masses can be distinguished: ms, "gravitational

source mass" which is the source of a gravitational field, mR,

"gravitationally reactant mass" which reacts to a gravitational

field, and mi, "inertial mass" which sets the relation between

force and acceleration (mi = F/a). Although these distinctions

were made to classically analyze the behavior of negative

mass, they do invite speculation. Could either a "source" or

"reactant" mass be mimicked through some coupling between

gravity, electromagnetism and spacetime? If so, the

propulsive effect suggested above may be possible. This is

unknown at this time.

Mathematically, this concept can be illustrated by the

following equations:

-Gm,

V= (5)

}(x-d)2+y2

where V isthegravitationalscalarpotentialplottedover an xy plane as a surfaceplotin figure7 which isequal to the

familiarNewton's gravitationalpotentialof thesourcemass,

m s,which isa distance,d, alongthe x axis,from thereactant

mass. The source mass is defined to have the property that it

only causes a field, but does not react to one. The reactant

mass is defined to react to the presence of a field, but not to

cause one. Thus, there is no force on the source mass from

the reactant mass.

To illustratehow thisconceptworks,examine thesum of

the resulting forces:

I:forces- Gmsmx i_msia+mma (6)

d_

The first term of the sum is the gravitational force from the

source mass, ms, acting on the reactant mass, m R . By

definition, there is no force created on the source mass from

the reactant mass, and hence, no term for that force in this

equation. However, to entertain the possibility that the source

and the reactant mass have inertial mass, terms are included for

the reaction forces due to these inea'tia. These reaction forces

are the second and third terms in the summation, where msi is

the inertia of the source mass and mRi is the inertia of the

reactant mass. Since it is assumed that the masses are rigidly

connected by whatever device has pulled them apart, the

acceleration, a, is the same for both masses. Solving for the

accelerationgives:

a= _ IIlsi+Inm

which acts in the positive x direction.
Marc G. Millis

Although existing evidence strongly suggests that active,

passive, and inertial mass are inseparable properties, any

future evidence to the contrary would have revolutionary

implication to this propulsion application.

5. REMAINING RESEARCH

There are a variety of unexplored paths toward discovering

the physics for a space drive. To explore the collision sail

concepts it would be useful to seek any means to interact

asymmetrically with the media that are known to exist in

space. In particular, the media of the electromagnetic

fluctuations of the vacuum, also called the ZPF, is a

promising candidate because of its high energy density.

A research approach to further explore the concept field

drives is to investigate the physics of negative mass. It is not

know whether negative mass exists, but methods have been

suggested to search for evidence of negative mass in the

context of searching for astronomical evidence of wormholes

[15]. If negative mass is found to exist and if methods can be

eventually engineerext to collect and handle negative mass, it

seems reasonable that a propulsive effect could be engineered

as previously discussed with the Diametric Drive. If negative

mass does not exist, it is still possible, in the spirit of the

Horizon Methodology, to consider the alternative of

artificially synthesizing negative mass effects using some asyet-undiscovered physics, perhaps using a form of gravityelectromagnetic coupling.

The idea of discovering some gravity-electromagnetic

coupling goes beyond the idea of mimicking negative mass.

If there is any way to modify gravity, inertia, or the properties

of spacetime using electromagnetics, it may be possible to

mimic negative mass to create a gravitational dipole, induce

gravitational or electromagnetic fields to create a Pitch Drive,

or modify other properties of space to create aBias Drive.

The idea of using one phenomenon to comrol another is

not new. Elecuic fields are used to create magnetic fields. By

knowing the specifics of how these phenomena are coupled, it

is possible to engineer such effects. In the case of a space

drive it is desired to create an acr.,eleration-inducing field using

some phenomenon like electromagnetics that can be readily

controlled.

Electromagnetism is suggested as the control

phenomenon for two reasons: electromagnetism is a

phenomenon for which we are technologically proficient, and

it is known that gravity, spacefime, and electromagnetism are

coupled phenomena. In the formalism of general relativity

this coupling is described in terms of how mass warps the

spacetime against which electromagnetism is measured. In

simple terms this has the consequence that gravity appears to

bend light, red-shift light and slow time. These observations

and the general relativistic formalism that describes them have

been experimentally supported [9]. Although gravity's effects

on electromagnetism and spacetime have been observed, the

reverse possibility, of using electromagnetism to affect

gravity, inertia, or spacetime is unknown. To explore this

possibility, it would be advantageous to have a formulation

that describes these observed couplings as a function of

electromagnetics.

Electromagnetism is also suggested as a target

phenomenon for space drive research because of the ZPF. The

ZPF is an electromagnetic phenomenon. Discovering any

way to react asymmetrically with the ZPF would likely create

a space drive. ZPF has also been theorized to be an

underlying phenomena to inertia and gravity [1, 2], and

experiments have been suggested to test these theories and to

test other related speculations on the relation between the ZPF

and mass properties [3]. It should be noted that these theories

were not written in the context of propulsion and do not

provide direct clues for how to elec_magnetically manipulate

inertia or gravity. Also, these theories are still too new to

have either been confirmed or discounted. Despite such

uncertainties these theories provide new, alternative

approaches to search for breakthrough propulsion physics.

Still another piece of evidence of possible gravity and

electromagnetic coupling is an experiment that indicates that

there may be a gravity shielding effect with superconductors

[16]. This effect has not yet been confirmed or discounted, so

it is premature to conclude thatsuch a gravity shielding effect

is real. It does, however, provide another research avenue for

space drive physics.

Inherent to all the propulsive mechanisms discussed

above is the need to generate an asymmetric field, one that

results in a net acceleratiou of the vehicle. One way to search

for such asymmetric effects is to search for nonlinear or nonconserved effects. If, for example, there exists some

characteristic coupling between electromagnetism, spacetime,

inertia, or gravity that behaves nonlinearly, has some

hysteresis, or is non-conserved (analogous to friction) it may

be possible to create net forces from imbalanced, cyclic

pemubafious of this effect.

To illustrate this possibility, consider the analogy of an

irregularly oscillating mass affLxed to a cart that is initially at

rest on the floor. When the mass moves slowly in one

direction its reaction forces are not sufficient to overcome the

static coefficient of friction between the cart and the floor and

the can remains still. When the mass moves quickly in the

other direction its reaction forces are sufficient to overcome

the static coefficient of friction, and the cart rolls. Repenting

this cycle results in a net motion of the cart. If there are any

field properties of space that have such a characteristic nonconserved interaction analogous to friction, then it may be

possible to create an analogous propulsive effect in space.

A more conventional example which better illustrates the

possibilities of nonlinear propulsion, is a method suggested

by Landis [17]. This concept outlines a technique for

changing the orbits of satellites without using propellant, and

does so using conventional physics. It uses tethers on a

satellite to take advantage of the nonlinear nature of a

gravitational well. If the orbiting satellite extends a tether
The Challenge to Create the Space Drive

toward Earth and another tether away from earth, the

imbalanced reactions will create a net force toward the Earth.

This is because the downward force on the near-F_aa_ tether

increases more than the outward force on the outer tether as

the tethers are deployed. By alternately deploying and

retracting long tethers at different points during the orbit

(apogee and perigee), an orbiting satellite can change its

orbital altitude or eccentricity.

Another approach is to revisit the field properties of space

itself in search of evidence of imbalanced forces. One

experiment to explore this possibility is where a homopolar

motor is used to illustrate a paradox of apparently imbalanced

magnetic reaction forces [18]. Another is from experimental

observations of unipolar induction that explores the relation

between magnetic fields and the surrounding space [19]. To

address the propulsive implications of this approach, the issue

of conservation of momentum and the role played by the

sm'rounding space would have to be fully addressed.

To fully develop ways to create such forces against the

properties of space, the issue of conservation of momentum

must be addressed. In the case of the tether example discuss_

above, the Earth acts as the reaction mass to conserve

momentum. In the case of negative mass propulsion,

conservation of momenlmn is satisfied by taking advantage of

the negative inertia of negative mass [14]. With the

remaining field drives, however, research will be required to

fred some other way to conserve momentum.

One approach to conserve momentum is to consider space

itself as the reaction mass. This approach evokes the old idea

of an "ether." To be strictly consistent with empirical

evidence, such as the Michelson-Morely experiment, any

further research to revisit the idea of an ether would have to

impose the condition that an ether is electromagnetically

Lorentz invariant- Note that this condition is a characteristic

of the ZPF [7].

An alternative to considering space as the reaction mass is

to further develop Mach's Principle. Mach's Principle asserts

that surrounding matter gives rise to inertial frames, and that

the inertial frames are somehow connected to the surrounding

matter [9]. Mach wrote that although he felt a connection to

the surrounding matter was required for the property of inertia

to be detectable, he also admitted that such a treatment was

not necessary to satisfactorily describe the laws of motion

[20]. Specifically, to be useful for propulsion physics, a

formalism of Mach's Principle is required that provides a

means to wansmit reaction forces to surrounding matter. This

implies developing a quantitative description for how the

surrounding matter creates an inertial frame, and how pushing

against that flame with a space drive is actually pushing

against the distant surrounding matter.

It is also possible to consider the very structure of

spacetime itself as a candidate for propulsive interactions. If it

were possible, for example, to create asymmetries in the very

properties of spacetime which give rise to inertial frames, it

may be possible to create net inertial forces. This is similar

to the"warp drive" suggested by Alcubierre [4]

It is also conceivable that other research aPlXOaches exist.

To further explore any of these possibilities, it would be

useful to have a succinct problem statement to guide the

evaluation and application of emerging science to the goal of

creating a space drive. Such a problem statement is offered

next.

6. PROBLEM STATEMENT

The critical issues for both the sail and field drives have

been compiled into the problem statement offered below.

Simply put. a space drive requires some controllable and

sustainable means to create asymmetric forces on the vehicle

without expelling a reaction mass, and some means to satisfy

conservation laws in the process. Regardless of which

concept is explored, the following criteria must be satisfied.

(1) A mechanism must exist to interact with a property of

space, matte_, or energy which satisfies these conditions:

(a) must be able to induce an unidirectional

acceleration of the vehicle.

(b) must be controllable.

(c) must be sustainable as the vehicle moves.

(d) must be effective enough to propel the vehicle.

(e) must satisfy conservation of momentum.

(f) must satisfy conservation of energy.

(2.1) If properties of matter or energy are used for the

Iropulsive effect, this matter or energy...

(a) must have properties that enable conservation of

momentum in the propulsive process.

b) must exist in a form that can be contronably

collected, carried, and positioned on the vehicle,

or be controllably created on the vehicle.

(c) must exist in sufficiently high quantities to

create a sufficient propulsive effect.

(2.2) If properties of space are used for the propulsive

effect, these properties...

(a) must provide an equivalent reaction mass to

conserve momentum.

Co) must be tangible; it must be able to be detected

and interacted with.

(c) must exist across all space and in all directions.

(d) must have a sufficiently high equivalent mass

density within the span of the vehicle to be used

as a propulsive reaction mass.

(e) must have characteristics that enable the

propulsive effect to be sustained once the vehicle

is in motion.

(3) The physics proposed for the propulsive mechanism and

for the properties of space, matter, or energy used for the

propulsive effect must be completely consistent with

empirical observafons.
Marc G. Millis

7. CONCLUSIONS

Prior to the emergence of new theories suggesting

connections between gravity, inertia, and the electromagnetic

fluctuations of the vacuum, and the recent "warp drive" theory,

the prospects for creating a space drive have seemed too far in

the future to provide near term reseurch opportunities. Now

with these emerging the.a_es, new research approaches exist.

To provide a framework for taking advantage of these

emerging theories and progressing science toward the goal of a

space drive, a problem statement was needed and is now

offered in this paper.

Regarding the prospects for breakthroughs, consider the

following quotes from past expects. These quotes were copied

from Anderson's article on the Horizon Methodology [6].

"Heavier than air flying machines are impossible,"

"Radio has no future,"

"X-rays are a hoax."

- William Thomson (Lord Kelvin)

President of London's Royal Society (1895-1904).

"There is no likelihood man can ever tap the power of the

atom. °°

- Robert Millikan,

Nobel Prize in Physics (1923).

"The secrets of flight will not be mastered within our

lifetime., not within a thousand years."

- Wilbur Wright (1901).

ACKNOWLEDGEMENTS

The following individuals conm'buted thought-provoking

questions and critical reviews that were instrumental in

completing this work: Mike Binder, Mike LaPointe, Ira T.

Myers, Bryan Palaszewski, and Ed Zampino.

REFERENCES

1. Haisch, B., Rueda, A. & Puthoff, H.E.,"Inertia as a

Zero-Point Field Lorentz Force", In Physical Review A, Vol.

49, No. 2, p. 678-694, (FEB 1994)

2. Puthoff, H.E., "Gravity as a zero-peint-flucmation force", In

Physical Review A, Vol.39, N. 5, (A89-33278),

p.2333-2342, (Mar 1, 1989).

3. Forward, R. L., Mass Modiftcation Experiment Definition

Study, PL-TR-96-3004, Final Report on Conl_act FO4700-

95-M-4216, Phillips Lab, Edwards Air Force Base, (Feb

1996).

4. Alcubierre, M., 'Whe warp drive: hyper-fast travel within

goneral relativity', In Classical and Quantum Gravity, Vol

11, p. L73-L77, (1994).

5. Millis, M. G., (NASA, Lewis Research Center), "Warp Drive,

When7", Presented at the National Space Society's 14th

Annual International Space Development Conference,

Cleveland Ohio, May 18-25 1995. Also on web site:

http:llww w.lerc.nasa.gov/Other_Groups/PAO/warp.htm

6. Anderson, J. L., "Leaps of the Imagination: Interstellar

Flight and the Horizon Mission Methodology", In Journal of

the British Interplanetary Society, Vol 49, pp. 15-20,

(1996).

7. Boyer,T.H_ 'TheClassical Vacuum'.In Scientifu: American,

p.70-78, (Aug 1985).

8. Muller,R.A. Whe Cosmic Background Radiation and the new

Aether Drift', In Scientific American, Vol.238, N.5,

p.64-74, (May 1978).

9. Misoer,C.W., Thome,K.S., and Wheeler,J.A., Gravitation,

W.H.Fremn_ & Co., New York (1973).

10. Kaufinmm, W. J. HL Black Holes and Warped Spacetime, pp

206-208, W. H. Freeman & Co., San Francisco, (1979).

11. Krauss, L. M., "Dark Matter in the Universe', In Scientific

American, p. 58-68, (Dec 1986).

12. Bondi, H., Negative Mass in General Relativity, In Reviews

of Modern Physics, VoL 29, No. 3, p 423-428, (July, 1957).

13. Winterberg, F., "On Negative Mass Propulsion', AIF Paper

89-668, 40th Congress of the International Astronautical

Federation, Malaga, Spain, (Oct, 1989).

14. Forward,R.L., "Negative Matter Propulsion', In Journal of

Propulsion and Power, Vol. 6, No. 1, p 28-37, (Jan - Feb,

1990).

15. Cramer, I., Forward. R.L., Morris, M., Visser, M., Benford,

G. and Landis, G., "Natural Wormholes as Gravitational

Lenses", In Physical Review D, p.3124-3127, 15 March

1995. 47th Symposium on Relativistic Astrophysics, MaxPlanck Institute for Physics. Munich. December 1994.

16. Podkletnov. E. and Nieminen* R. "A possibility of

gravitational force shielding by bulk YBa2 Cu30T.x

superconductor" Physica, Vol C203, 441-444 (1992).

17. Landis, G. A. and Hrach, F. L., "Satellite Relocation by

Tether Deployment", NASA TM 101992, (Atnil 1989).

18. Eagleton, R. D. (Dept of Phys, California State Polytechnic

Univ., Pomona CA 91768), and Kaphm, M. N., "The radial

magnetic field homopolar motor", In American Journal of

Physics, Vol. 56, No. 9, p. 858-859, (Sep 1988).

19. Kennard, E.H., "On Unipolar Induction: Another Experiment

and its Significance as Evidence for the Existence of the

AEther", In Philosophical Magazine, Vol.33, p.179-190,

(1917).

20. Mach, E., The Science of Mechanics, Fifth Edition. Open

Court Publishing Co, London, (1942).

REPORT DOCUMENTATION PAGE I Form OMBNo. Approved 0704-0188

eu/o_i¢ reporting 10u_le_ for this coils=ion of int'ormation is =Umated to average 1 ho_ per response, inofud,_ the time f_ rev'._n_.t .ll=_n_, _ =_'."_1 dala _u_c_i_

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

August 1996 Technical Memorandum

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

The Challenge to Create the Space Drive

6. AUTHOR(S)

Marc G. MUlls

7. PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES)

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135-3191

9. SPONSORIN_NITORING AGENCYNAME(S)ANDADDRESS(ES)

National Aeronautics and Space Administration

Washington, D.C. 20546-0001

WU-None

8. PERFORMING ORGANIZATION

REPORT NUMBER

E- 10365

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

NASA TM- 107289

11. SUPPLEMENTARYNOTES

Prepared for the Interstellar Flight Symposium of the 15th Annual International Space Development Conference sponsored by the National Space Society, New York, NewYork, May 23-24, 1996. Responsible person, Marc G. Millis,

organization code 5340, (216) 977-7535.

12a. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified -Unlimited

Subject Category 70

This publication is available from the NASA Center forAezoSpace Information, (301) 621--0390

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

To travel to our neighboring stars as practically as envisioned by science fiction, breakthroughs in science are required.

One of these breakthroughs is to discover a self-contained means of propulsion that requires no propellant. To chart a

path toward such a discovery, seven hypothetical space drives are presented to illustrate the specific unsolved challenges

and associated research objectives toward this ambition. One research objective is to discover a means to asymmetrically

interact with the electromagnetic fluctuations of the vacuum. Another is to develop a physics that describes inertia,

gravity, or the properties of spacetime as a function of electromagnetics that leads to using electomagnetic technology for

inducing propulsive forces. Another is to determine if negative mass exists or if its properties can be synthesized. An

alternative approach that covers the possibility that negative mass might not exist is to develop a formalism of Mach's

Principle or reformulate ether concepts to lay a foundation for addressing reaction forces and conservation of momentum

with space drives.

14. SUBJECT TERMS

Gravitation; Electromagnetism; Antigravity; Warp drive; Faster-than-light;

Spacecraft propulsion; General physics

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OF REPORT

Unclassified

18. SECURITY CLASSIRCATION

OF THIS PAGE

Unclassified

19. SECURITY CLASSIFICATION

OF ABSTRACT

Unclassified

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]0

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A02

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