This paper discusses theoretical solutions for interstellar travel, including fusion drives, solar sails, and warp drives. Fusion drives could propel a ship to 10-20% the speed of light using contained fusion reactions, allowing travel within 20 light years. Solar sails, the only existing technology, could reach 60% light speed with powerful lasers and travel to nearby stars within a human lifespan. A hypothetical warp drive could contract space in front and expand it behind, riding a wave of spacetime and allowing travel faster than light, though this technology is at least 100 years away. While interstellar travel poses huge technological challenges, developing these solutions could allow humanity to spread beyond the solar system.

1. Melvin Hoyer III
Senior Seminar
Technical paper
1/24/14
Theoretical Solutions to Interstellar Travel
Biology on planet earth is driven by the ability of evolution and Adaptation by life forms
to secure survival of the next generation. While the Human race has only been around on this
planet for a tiny fraction of its entire history, we have continually grown into an apex species
like none seen on this planet previously. All great inventions and innovations of the human
mind have been in the pursuit of breaking bonds with our current surroundings in order to
maximize survival of the following generation. As we lay on the cusp of branching out from our
planet to the next in our solar system (A feat impossible a mere 30 years ago) one must begin
to think what truly lies beyond. Our planet let alone our entire solar systemare not eternal and
one day will be gone. However if future generations can harness the power of the laws of
physics themselves our species can break free of the bonds of this solar system, just as the
wright brothers broke free the bonds of gravity with manned flight. As the rapid development
of new technology grows ever faster and the voyager mission officially leaving our solar system
interstellar travel can no longer be pushed to the side as science fiction. However the method
of which we travel through space now is crude and highly inefficient making interstellar travel
with this technology highly ineffective and nearly impossible. This forces us to think of a new
more exotic way of getting us from Point A to B in the universe. We will explore these exotic
propulsion systems how they work and the fuel needed to propel them.

2. In order to begin the discussion of Interstellar travel one must recognize the vast
distances involved. The space in between stars are on the order of light years, which makes
travel between them by current means nearly impossible. One light year is the distance light
travels in one year, with a single photon moving at 186,282 mi/s, and the nearest star system
4.3 light years away Voyager 2 would take 500 years to arrive by conventional means. Only by
achieving a significant fraction of the speed of light will manned travel between the stars
become attainable in a single human lifespan. However due to time dilation predicted by
Einstein’s Theory of relativity the closer an object approaches to luminal speed the slower its
clock moves relative to another slower object.
∆𝑡 = 𝛾∆𝑡′
∆𝑡 Being the time experienced by on outside observer and ∆𝑡′ being the time experienced by
the crew.
𝛾 ≡
1
√1 − 𝛽2
with, 𝛽 =
𝑣
𝑐
, v being velocity and c the speed of light, these equations show that when
traveling at relativistic speeds time dilation would be a legitimate concern for future interstellar
travelers if raw velocity is their means of travel. Where if they’re on a 20 year mission traveling
at 𝑣 = 0.6𝑐 a 20 year mission experienced by the crew, 35 years would have passed on earth.
Traveling at relativistic speeds also causes an object to gain mass meaning chemical rockets are
totally impractical because the faster the object the amount of fuel required to accelerate a

3. little amount requires more and more fuel. To counter this new and exotic forms of propulsion
need to be introduced.
Interstellar travel will require propulsion systems based on technology and ideas already
in development today. Ideas such as sustained and contained fusion reactions, Solar sails,
powerful lasers, and the search for the presence of negative mass particles will someday allow
humans to travel the Universe. These and many other ideas and experiments give rise to three
theoretically possible interstellar propulsion systems the Fusion drive, Solar Sail, and Warp
Drive. Each could allow for travel between at least the nearest stars in a single human lifespan.
They each have their advantages and disadvantages due to shear engineering or time dilation
due to relativistic speeds achieved but the possibility of branching the human race beyond one
solar system is the greatest advantage of all.
The Fusion Drive recreates the natural fusion process ongoing in stars and uses the raw
kinetic energy from a contained reaction to propel a ship. Pure Fusion technology is already in
development today with the Tokomak which is a giant magnetic containment reactor and
inertial confinement fusion (ICF) reactors that use enormously amplified lasers fired at a small
target. A true fusion drive for a ship would require a merging of these technologies to allow for
a system that could propel a ship to about 10-20% the speed of light. Through a series of
controlled fusion reactions ignited by inertial confinement and contained magnetically would
create huge amounts of thrust from a tiny fuel supply roughly 1/25th the mass of the ship.
However because of non-relativistic speeds (.20c) this drive is limited to interstellar missions up
to 20 light years away from earth within one lifespan.

4. Solar Sail technology out of the three propulsion methods proposed is the only one in
application today on space craft but nowhere near the velocities needed for interstellar travel.
The sail is completely free of chemical propellant using the force of the solar wind to move it.
However in order for a solar sail to be an effective means of interstellar travel a way of exerting
a continuous force on it must be devised for when it is no longer influenced by a solar wind.
This force can be attained through the use of GigaWatt power lasers or masers. A sail required
to move a starship itself would need to be at least a square mile with 4 of these powerful lasers
fired at it continuously for 3 years could accelerate the craft to around 60% of the speed of
light. Neglecting the engineering required this becomes a highly practical and achievable mode
of travel to the stars. This technology could very well be in use before the end of the century
and could be the first means of interstellar travel developed. Due to the relativistic velocity that
could be attained time dilation would be experienced by the crew. A mission of 14 years
experienced by the crew 20 years would pass on earth because of this relatively low factor of
time dilation the solar sail becomes an even more attractive and practical interstellar
propulsion system.
In science fiction the idea of moving faster than light is looked at as a useful tool that
allows characters to travel great distances in no time at all. Most craft in science fiction use
some sort of “warp drive” but could such a propulsion system really be made reasonably?
While it is recognized that nothing can move faster than light, through the physics involved with
the expansion of the early universe space itself expanded faster than light could travel through
it. A warp drive could theoretically be possible if one is able to take advantage of the ability of
empty space to expand faster than light. If a warp bubble is maintained around the craft the

5. warp drive itself would contract the space in front of the bubble and expand the space behind it
allowing the ship to ride a wave of space-time faster than light can travel through a vacuum.
This creates a situation where the ship itself is not moving but moving space around it and the
crew would feel no effects of acceleration or extreme tidal forces. At such extreme velocities
travel to the nearest stars could be on the order of a few weeks. This exotic from of travel could
even leave the door open to time travel to the future because if relativistic effects are felt by
the crew the time dilation experienced by the crew would be exponential. This technology
would require exotic matter in order to create the warp bubble and to contract the space in
front of the craft. A form of exotic matter would be that with negative mass, experiments to
detect this negative mass are under way with the Casmir Effect apparatus. This experiment
aimed at detecting the spontaneous creation of negative virtual protons between two closely
placed mirrors in a vacuum. Even though photons are unimaginably small and are nearly pure
Energy as predicted by Einstein’s
𝐸 = 𝑚𝑐2
They too have a mass and if negative photons exist negative mass versions of other particles
must therefore exist. The fuel required to cause the contraction and expansion in front of the
craft could be “Dark Energy”, which is currently driving the acceleration of the expansion of the
universe. If the more studies are done on dark matter and a method of harnessing it would
make this Propulsion systempossible. This technology is completely theoretical and is easily at
least 100 years away.

6. Although the research of interstellar travel is more speculation than applicable with
today's technology with enough time and effort the stars could become the next great
exploratory period in human history. Most great scientific discoveries began as simple
conjecture and were laughed upon as impossible. However the reward of developing this
technology will far outweigh the risk in undertaking. Once bounds are broken from this solar
system just how far will humanity spread?

7. References
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sailing.html>.
• Dunbar, Brian. NASA. NASA, 23 Nov. 2004. Web. 26 Jan. 2014.
<http://www.nasa.gov/centers/glenn/technology/warp/warpstat_prt.htm>.
• "Alcubierre Drive." Wikipedia. Wikimedia Foundation, 15 Jan. 2014. Web. 27 Jan. 2014.
<http://en.wikipedia.org/wiki/Alcubierre_drive>.
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<http://en.wikipedia.org/wiki/Fusion_power>.
• Singh, Jasprit. Modern Physics for Engineers. New York: J. Wiley, 1999. Print.
• Burns, Marshall L. "Basic Concepts of Einstien Relativity." Modern Physics for Science
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