Why Now?
Source: Glenn Research Center
There comes a point when it is time to seek the next
revolutions in technology. That point is when the existing methods are
reaching the limits of their performance and new possibilities are
emerging for alternative methods that might exceed those limits. The
limits of ground transportation were surpassed by aircraft. The
altitude limits of aircraft were surpassed by rockets. And now, rocket
technology is approaching the performance limits of its underlying
physical principles. To break through the limitations of rockets, it
is necessary to search for alternative propulsion methods with
different physical principles. New theories and physical effects have
emerged in recent scientific literature that may provide such
alternatives. To shape these emerging possibilities to answer the
propulsion needs of NASA, the Breakthrough Propulsion Physics Project
was established.
Rocket technology is fundamentally limited by its need
for propellant. The farther, faster, or more payload carried, the more
propellant that is required. This limit cannot be overcome with
engineering refinements. This limitation is based on the underlying
physical principles of all rocket propulsion - the very physics of its
operation. Because a rocket's reaction mass, its propellant, must be
carried with the rocket, propellant needs rise exponentially with
increases in payload, destinations, or speed. This is true for all
forms of rocket technology, from the chemical engines of the Shuttle,
through all envisioned nuclear rockets, and even electric ion
thrusters. For human journeys into orbit, to the Moon, or to Mars,
rocket technology is adequate. For robotic probes to the outer planets
of our Solar System, rocket technology is also adequate. However, to
dramatically reduce the expense of these journeys or to journey beyond
these points in a reasonable time, some new, alternative propulsion
physics is required.
Recent advances in science have reawakened consideration
that new propulsion mechanisms may lie in wait of discovery. For
example, recent experiments and Quantum theory have revealed that
space might contain enormous levels of vacuum electromagnetic energy.
This has led to questioning if this vacuum energy can be used as an
energy source or a propulsive medium for space travel. Next, new
theories speculate that gravity and inertia are electromagnetic
effects related to this vacuum energy. It is known from observed
phenomena and from the established physics of General Relativity that
gravity, electromagnetism, and spacetime are inter-related phenomena.
These ideas have led to questioning if gravitational or
inertial forces can be created or modified using electromagnetism.
Also, theories have emerged about the nature of spacetime that suggest
that the light-speed barrier described by Special Relativity might be
circumvented by altering spacetime itself. These "wormhole" and "warp
drive" theories have reawakened consideration that the light-speed
limit of space travel may be circumvented. Today, it is still unknown
whether these emerging theories are correct and, even if they are
correct, if they will become viable candidates for creating propulsion
breakthroughs.
To space technologists such emerging possibilities are
of keen interest. The propulsive implications of such emerging science
is not a major concern to the general scientific community, however.
Instead, much of modern physics is focused on understanding the
origins and age of the universe, answering the question of the missing
matter of the universe, and probing the physics of black holes and
high-energy particle interactions.
In 1990, a team of Lewis Research Center volunteers
began an effort to formulate the questions and search for ideas from
the scientific literature related to the possibility of creating a
"field-drive" propulsion. This informal and unofficial group, called
The "Space-Coupling Propulsion and Power Working Group, conducted some
experiments and theoretical investigations, and forged collaborations
with other scientists and engineers from other NASA centers, other
government laboratories, universities, and industry. In particular,
this group helped create a growing awareness of the opportunities
emerging from science and the need to apply these opportunities to
overcome the limitations of rocket technology.
In 1996, following a re-organization of NASA, the
Marshall Space Flight Center was tasked to formulate a comprehensive
strategy for advancing propulsion technology for the next 25 years.
This strategy, called the Advanced Space Transportation Program
(ASTP), spans the nearer-term technology improvements for launchers
all the way through seeking the breakthroughs that could revolutionize
space travel and enable interstellar voyages. To address the most
visionary end of this scale, the Marshall Space Flight Center sought
out the work of this Lewis Research Center team. Marc G. Millis, the
leader of the Lewis team, assembled a group of government, university,
and industry researchers to propose the Breakthrough Propulsion
Physics Project, as a part of this Advanced Space Transportation
Program. In July, 1996, this Breakthrough Propulsion Physics Project
was formally established.
The Breakthrough Propulsion Physics Project supports the
scientific study of motion through space with the goal of discovering
breakthrough means to propel spacecraft farther, faster, and more
efficiently. Specifically, this project aims to produce near-term,
credible, and measurable progress toward conquering the following 3
breakthrough goals:
(1) MASS: Discover new propulsion methods that eliminate
or dramatically reduce the need for propellant. This implies
discovering fundamentally new ways to create motion, presumably by
interactions between matter, fields, and spacetime, including the
possibility of manipulating gravity or inertia.
(2) SPEED: Discover how to attain the ultimate transit
speed to dramatically reduce travel times. This implies discovering a
means to move a vehicle at or near the actual maximum speed limit for
motion through space or by the motion of spacetime itself (if
possible, this means circumventing the light-speed limit).
(3) ENERGY: Discover fundamentally new modes of onboard
energy generation to power these propulsion devices. This third goal
is included since the first two breakthroughs could require
breakthroughs in energy generation, and since the physics underlying
the propulsion goals is closely linked to energy physics.
http://www.grc.nasa.gov/WWW/bpp/bpp_WHY.htm