172:. The differential sail is a speculative drive, based on the possibility of inducing differences in the pressure of vacuum fluctuations on either side of a sail-like structure — with the pressure being somehow reduced on the forward surface of the sail, but pushing as normal on the aft surface — and thus propel a vehicle forward.
49:
minor grant. At the end of the project, conclusions into fourteen topics, including these funded projects, were summarized by program manager Marc G. Millis. Of these, six research avenues were found to be nonviable, four were identified as opportunities for continued research, and four remain unresolved.
175:
The
Casimir effect was investigated experimentally and analytically under the Breakthrough Propulsion Physics project. This included the construction of MicroElectroMechanical (MEM) rectangular Casimir cavities. Theoretical work showed that the effect could be used to create net forces, although the
48:
The
Breakthrough Propulsion Physics project addressed a selection of "incremental and affordable" research questions towards the overall goal of propellantless propulsion, hyperfast travel, and breakthrough propulsion methods. It selected and funded five external projects, two in-house tasks and one
120:
The project then considered the mechanisms behind these drives. At the end of the project, three mechanisms were identified as areas for future research. One considers the possibility of a reaction mass in seemingly empty space, for example in
93:
A possible torsion-like effect in the coupling between electromagnetism and spacetime, which may ultimately be useful for propulsion, was sought in experiments. The experiments were insufficient to resolve the question.
89:
of inducing transient inertia by electromagnetic fields. The small effect could not be confirmed. Woodward continued refining the experiments and theory. Independent experiments also remained inconclusive.
112:
As a motivation, seven examples of hypothetical space drives were described at the onset of the project. These included the gravity-based pitch drive, bias drive, disjunction drive and diametric drive; the
40:
that would require breakthroughs in physics before they could be realized. The project ended in 2002, when the
Advanced Space Transportation Program was reorganized and all speculative research (less than
60:
Another experiment examined a gravity shielding mechanism claimed by
Podkletnov and Nieminen. Experimental investigation on the BPPP and other experiments found no evidence of the effect.
209:
551:
Hathaway, G; Cleveland, B; Bao, Y (April 2003). "Gravity modification experiment using a rotating superconducting disk and radio frequency fields".
66:
Other approaches categorized as non-viable are oscillation thrusters and gyroscopic antigravity, Hooper antigravity coils, and coronal blowers.
894:
Maclay, G. Jordan; Forward, Robert L. (March 2004). "A Gedanken
Spacecraft that Operates Using the Quantum Vacuum (Dynamic Casimir Effect)".
859:
Maclay, G. Jordan (17 April 2000). "Analysis of zero-point electromagnetic energy and
Casimir forces in conducting rectangular cavities".
176:
forces would be extremely small. At the conclusion of the project, the
Casimir effect was categorized as an avenue for future research.
63:
Research on quantum tunneling was sponsored by the BPPP. It was concluded that this is not a mechanism for faster-than-light travel.
494:
Podkletnov, E.; Nieminen, R. (December 1992). "A possibility of gravitational force shielding by bulk YBa2Cu3O7−x superconductor".
57:
One in-house experiment tested the
Schlicher thruster antenna, claimed by Schlicher to generate thrust. No thrust was observed.
45:
3) was cancelled. During its six years of operational funding, this program received a total investment of $ 1.2 million.
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After funding ended, program manager Marc G. Millis was supported by NASA to complete documentation of results. The book
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Davis, Eric W.; Gilster, Paul A. (2009). "Recent
History of Breakthrough Propulsion Studies". In Millis, Marc G. (ed.).
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Woodward, James F. (October 1990). "A new experimental approach to Mach's principle and relativistic graviation".
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Schlicher, R; Biggs, A; Tedeschi, W (1995). "Mechanical propulsion from unsymmetrical magnetic induction fields".
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electromagnetic momentum, interpreting inertia and gravity quantum vacuum effects, and the
Podkletnov force beam.
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Robertson, Tony; Lichford, Ron; Peters, Randall; Thompson, Byran; Rogers, Stephen L. (Jan 1, 2001).
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78:(deep Dirac levels) was carried out. Some states were ruled out, but the problem remains unsolved.
531:"Exploration of Anomalous Gravity Effects by rf-Pumped Magnetized High-T(c) Superconducting Oxides"
33:
109:
One of the eight tasks funded by the BPP program was to define a strategy towards space drives.
141:. A third research avenue that might ultimately prove useful for spacecraft propulsion is the
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Woodward, James F. (October 1991). "Measurements of a Machian transient mass fluctuation".
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Following program cancellation in 2002, Millis and others founded the Tau Zero Foundation.
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implies that there is no such thing as an exact amount of energy in an exact location,
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AIAA Joint Propulsion Conference; 8-11 Jul. 2001; Salt Lake City, UT; United States
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in February 2009, providing a deeper explanation of several propulsion methods.
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Other theories listed in Millis's final assessment as unresolved are
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357:. Reston, Va.: American Institute of Aeronautics and Astronautics.
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950:, AIAA, Progress in Astronautics & Aeronautics Vol 227, 2009.
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Ringermacher, Harry I. (1994). "An electrodynamic connection".
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189:
29:
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Cramer, John; Cassisi, Damon; Fey, Curran (Oct 1, 2004).
674:"Tests of Mach's Principle with a mechanical oscillator"
456:"Experimental results of Schlicher's thrusting antenna"
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are known to lead to discernible effects such as the
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387:"Prospects for Breakthrough Propulsion From Physics"
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210:United States gravity control propulsion research
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32:from 1996 to 2002 to study various proposals for
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454:Fralick, Gustave; Niedra, Janis (Nov 1, 2001).
153:One topic of investigations was the use of the
74:A theoretical examination of additional atomic
259:"Assessing Potential Propulsion Breakthroughs"
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18:Breakthrough Propulsion Physics Project
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776:"Challenge to Create the Space Drive"
133:. Another approach is to reconsider
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833:DiChristina, Mariette (May 2001).
774:Millis, Marc G. (September 1997).
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149:Quantum vacuum energy experiments
948:Frontiers of Propulsion Science
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783:Journal of Propulsion and Power
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355:Frontiers of propulsion science
257:Millis, Mark G. (Dec 1, 2005).
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631:Foundations of Physics Letters
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143:coupling of fundamental forces
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553:Physica C: Superconductivity
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496:Physica C: Superconductivity
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43:Technology readiness level
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385:Millis, Mark G. (2004).
286:10.1196/annals.1370.023
991:Scientific speculation
896:Foundations of Physics
412:Cite journal requires
145:on sub-atomic scales.
986:Spacecraft propulsion
188:was published by the
162:uncertainty principle
70:Unresolved approaches
53:Non-viable approaches
38:spacecraft propulsion
981:Interstellar travel
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689:10.2514/6.2001-3908
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508:1992PhyC..203..441P
471:10.2514/6.2001-3657
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180:Tau Zero Foundation
166:vacuum fluctuations
81:Experiments tested
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28:funded by
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