NASA is funding Mach effect propulsion in the latest round of advanced concept projects.

Nextbigfuture has covered Woodwards Mach effect propulsion in dozens of articles.

They propose to study the implementation of an innovative thrust producing technology for use in NASA missions involving in space main propulsion. Mach Effect Thruster (MET) propulsion is based on peer-reviewed, technically credible physics. Mach effects are transient variations in the rest masses of objects that simultaneously experience accelerations and internal energy changes. They are predicted by standard physics where Mach’s principle applies – as discussed in peer-reviewed papers spanning 20 years and a recent book, Making Starships and Stargates: the Science of Interstellar Transport and Absurdly Benign Wormholes published recently by Springer-Verlag. These effects have the revolutionary capability to produce thrust without the irreversible ejection of propellant, eliminating the need to carry propellant as required with most other propulsion systems.

Their initial Phase I effort will have three tasks, two experimental and one analytical:

1. Improvement of the current laboratory-scale devices, in order to provide long duration thrust at levels required for practical propulsion applications.

2. Design and development of a power supply and electrical systems to provide feedback and control of the input AC voltage, and resonant frequency, that determine the efficiency of the MET.

3. Improve theoretical thrust predictions and build a reliable model of the device to assist in perfecting the design. Predict maximum thrust achievable by one device and how large an array of thrusters would be required to send a probe, of size 1.5m diameter by 3m, of total mass 1245 Kg including a modest 400 Kg of payload, a distance of 8 light years (ly) away.

*Mach Effects for In Space Propulsion: Interstellar Mission Credits: Heidi Fearn*

Ultimately, once proven in flight and after more development, these thrusters could be used for primary mission propulsion, opening up the solar system and making interstellar missions a reality. The MET device is not a rocket, it does not expel fuel mass, and does not suffer from the velocity restriction of rockets. Freedom from the need to expel propellant means very high velocities might be achievable simply by providing electrical power and adequate heat rejection for the drive system. A mission to Planet 9 (or Planet X as it has been called) is possible in the near future using RTG power and thruster arrays. A future goal would be interstellar travel to the nearest exoplanet, within 5-9 ly distance. A mission of this type might take 20 or more years using the MET thruster. Although the nearest exoplanet is 14 or so ly distance, more Earth-like planets are being discovered daily.

This exciting TRL 1 technology, ready to take the next step to providing propellantless propulsion, first in incremental NASA smallsat missions, but later enabling revolutionary new deep space exploratory capabilities beyond anything achievable by conventional chemical, nuclear or electric propulsion systems. This unexplored opportunity has been uniquely developed by our co-Principal Investigators, breaking new ground in both science and engineering. Finally, it is technically credible – if bold and unconventional – and is fully consistent with modern physics, having been demonstrated over ten years of careful laboratory demonstration and investigation.

If the Woodward effect is confirmed and if an engine can be designed to use applied Mach effects, then a spacecraft may be possible that could maintain a steady acceleration into and through interstellar space without the need to carry along propellants. Woodward presented a paper about the concept at the NASA Breakthrough Propulsion Physics Program Workshop conference in 1997 and continued to publish on this subject thereafter.

Even ignoring for the moment the impact on interstellar travel, future spacecraft driven by impulse engines based on Mach effects would represent an astounding breakthrough in terms of interplanetary spaceflight alone, enabling the rapid colonization of the entire solar system. Travel times being limited only by the specific power of the available power supplies and the acceleration human physiology can endure, they would allow crews to reach any moon or planet in our solar system in less than three weeks. For example, a typical one-way trip at an acceleration of 1 g from the Earth to the Moon would last only about 4 hours; to Mars, 2 to 5 days; to the asteroid belt, 5 to 6 days; and to Jupiter, 6 to 7 days.

**Theory of a Mach Effect Thruster I**

The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass—energy fluctuations. Mach’s principle is a statement that the inertia of a body is the result of the gravitational interaction of the body with the rest of the mass-energy in the universe. The MET device uses electric power of 100 – 200 Watts to operate. The thrust produced by these devices, at the present time, are small on the order of a few micro-Newtons. Researchers give a physical description of the MET device and apparatus for measuring thrusts. Next they explain the basic theory behind the device which involves gravitation and advanced waves to incorporate instantaneous action at a distance. The advanced wave concept is a means to conserve momentum of the system with the universe. There is no momentun violation in this theory. We briefly review absorber theory by summarizing Dirac, Wheeler-Feynman and Hoyle-Narlikar (HN). They show how Woodward’s mass fluctuation formula can be derived from first principles using the HN-theory which is a fully Machian version of Einstein’s relativity. HN-theory reduces to Einstein’s field equations in the limit of smooth fluid distribution of matter and a simple coordinate transformation.

It is shown that if Mach’s Principle is taken seriously, and the inertia of a body can be described as the interaction of the body with the rest of the universe, then the advanced and retarded fields transmitted between the particle and the universe can be used to explain the thrust observed in the Mach Effect drive experiments. This idea was originally put forward by one of the authors, James Woodward. The idea of inertia being a gravitational effect was first postulated by Einstein. In fact Mach’s principle was the foundation on which Einstein’s general relativity was based

**Theory of a Mach Effect Thruster II**

According to Einstein, General Relativity contains the essence of Mach’s ideas. Mach’s principle can be summarized by stating that the inertia of a body is determined by the rest of the mass-energy content of the universe. Inertia here arises from mass-energy there. The latter, was a statement made by John Wheeler in his 1995 book, Gravitation and Inertia, coauthored by Ciufolini. Einstein believed that to be fully Machian, gravity would need a radiative component, an action-at-a-distance character, so that gravitational influences on a body from far away could be felt immediately. In 1960’s, Hoyle and Narlikar (HN) developed such a theory which was a gravitational version of the Absorber theory derived by Wheeler-Feynman for classical electrodynamics and later expanded upon by Davies and Narlikar for quantum electrodynamics. The HN-field equation has the same type of mass fluctuation terms as in the Woodward Mach effect thruster theory. The force equation, used to predict the thrust in our device, can be derived from the mass fluctuation. We outline a new method for deriving the force equation. We present new experimental tests of the thruster to show that the thrust seen in our device is not due to either heating or Dean Drive effects. Successful replications have been performed by groups in Austria and Canada, but their work is still pending in the peer review literature.

**New Theoretical Results for the Mach Effect Thruster**

Einstein believed that his general relativity theory contained the essence of Mach’s ideas. That a mass is determined by the rest of the mass-energy content of the universe. Inertia here arises from mass-energy there. The latter, an opinion shared by John Wheeler. Einstein believed that to be fully Machian, gravity would need a radiative component, an action-at-a-distance character, so that gravitational influences from far away could be felt immediately by a particle. Hoyle and Narlikar in the 1960’s developed such a theory which was a gravitational version of the Absorber theory derived by Wheeler–Feynman for classical electrodynamics. Hawking in 1965 showed that the mass, from the advanced wave integral in the Hoyle Narlikar theory, was divergent. It can be shown that the advanced wave integral is finite when the cosmic event horizon, due to the acceleration of the universe, is taken into consideration. The HN-theory is directly related to the mass fluctuation equations in the Woodward Mach effect thruster theory. The connection between the theories will be made clear, also presented is new experimental data from the past 6 months.

**Mach’s Principle, Action at a Distance and Cosmology**

Hoyle and Narlikar (HN) in the 1960’s developed a theory of gravitation which was completely Machian and used both retarded and advanced waves to communicate gravitational influence between particles. The advanced waves, which travel backward in time, are difficult to visualize and although they are mathematically allowed by relativistic wave equations, they never really caught on. The HN theory reduced to Einstein’s theory of gravity in the smooth fluid approximation and a transformation into the rest frame of the fluid. Hawking in 1965 pointed out a possible flaw in the theory. This involved integrating out into the distant future to account for all the advanced waves which might influence the mass of a particle here and now. Hawking used infinity as his upper time limit and showed the integral was divergent. We point out that since the universe is known to be expanding, and accelerating, the upper limit in the advanced wave time integral should not be infinite but is bounded by the Cosmic Event Horizon. This event horizon He represents a barrier between future events that can be observed and those which cannot. We show that the advanced wave integral is finite when H c e , is used as the upper limit of the advanced wave integral. Hawking’s objection is no longer valid and the HN theory becomes a working theory once again

**Mach Effect Thrusters would not violate over unity energy production**

Mach Effect Thrusters (Mets) And “Over-Unity” Energy Production

Woodward and Hearn routinely hear a criticism of METs based upon an argument that claims: if a MET is operated at constant power input for a sufficiently long time, it will acquire enough kinetic energy to exceed the total input energy of operation. Assuming this argument to be correct, critics assert that METs violate energy conservation as the ratio of the acquired kinetic energy to total input energy exceeds “unity.”

Contrary to this “over-unity” assumption, this argument is based on flawed physics and, consequently, wrong. The fact that the argument applies to all simple mechanical systems (in addition to METs) should have alerted critics to their mistake. But it didn’t. So, a dumb idea that should have been quickly buried is still with us. The purpose of this essay is to carry out a long overdue burial.

In brief, the “over-unity” argument asserts that a constant input power into a MET will produce a constant thrust (force). This, in turn, produces a constant acceleration of any object to which the MET is attached. The constant acceleration produces a linearly increasing velocity of the object. The kinetic energy of the object, however, increases as the square of the velocity. This means that at some point, the kinetic energy of the object will exceed the total input energy used to produce the thrust as that only increases linearly with time. Critics then claimed that this purported behavior constituted violation of energy conservation and proposed it as a fatal critique of Mach Effect thrusters. Note, however, that the argument applies to all systems where a constant thrust produced by a constant input power produces motion.

Velocity is not an invariant quantity as it depends on the motion of the observer as well as any velocity ascribed to motion in some other reference frame. The principle of relativity precludes singling out any particular observer as privileged over all others