Breakthrough Propulsion Physics Program
The Breakthrough Propulsion Physics Project (BPP) was a research project funded by NASA from 1996-2002 to study various proposals for revolutionary methods of spacecraft propulsion 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 Technology readiness level 3) was cancelled. During its six years of operational funding, this program received a total investment of $1.2 million.
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 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.
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.
Other approaches categorized as non-viable are oscillation thrusters and gyroscopic antigravity, Hooper antigravity coils, and coronal blowers.
Experiments tested Woodward’s theory 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.
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.
Other theories listed in Millis's final assessment as unresolved are Abraham–Minkowski electromagnetic momentum, interpreting inertia and gravity quantum vacuum effects, and the Podkletnov force beam.
One of the eight tasks funded by the BPP program was to define a strategy towards space drives.
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 Alcubierre drive; and the vacuum energy based differential sail.
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 dark matter, dark energy, or zero-point energy. Another approach is to reconsider Mach's principle and Euclidean space. A third research avenue that might ultimately prove useful for spacecraft propulsion is the coupling of fundamental forces on sub-atomic scales.
Quantum vacuum energy experiments
One topic of investigations was the use of the zero-point energy field. As the Heisenberg uncertainty principle implies that there is no such thing as an exact amount of energy in an exact location, vacuum fluctuations are known to lead to discernible effects such as the Casimir effect. 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 raft surface — and thus propel a vehicle forward.
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 forces would be extremely small. At the conclusion of the project, the Casimir effect was categorized as an avenue for future research.
Tau Zero Foundation
After funding ended, program manager Marc G. Millis was supported by NASA to complete documentation of results. The book Frontiers of Propulsion Science was published by the AIAA in February 2009, providing a deeper explanation of several propulsion methods.
Following program cancellation in 2002, Millis and others founded the Tau Zero Foundation.
- Millis, Mark G. (Dec 1, 2005). "Assessing Potential Propulsion Breakthroughs" (PDF). New Trends in Astrodynamics and Applications 2: An International Conference; 3-5 Jun. 2005; Princeton, NJ; United States. 1065: 441–461. Bibcode:2005NYASA1065..441M. doi:10.1196/annals.1370.023. hdl:2060/20060000022. PMID 16510425. Retrieved 8 February 2018.
- Davis, edited by Marc G. Millis, Eric W.; Gilster, Paul A. (chapter author) (2009). "Recent History of Breakthrough Propulsion Studies". Frontiers of propulsion science. Reston, Va.: American Institute of Aeronautics and Astronautics. ISBN 9781615830770.CS1 maint: Extra text: authors list (link)
- Millis, Mark G. (2004). "Prospects for Breakthrough Propulsion From Physics" (PDF). Retrieved 8 February 2018.
- Schlicher, R; Biggs, A; Tedeschi, W (1995). "Mechanical propulsion from unsymmetrical magnetic induction fields". 31st Joint Propulsion Conference and Exhibit: 2643. doi:10.2514/6.1995-2643.
- Fralick, Gustave; Niedra, Janis (Nov 1, 2001). "Experimental results of Schlicher's thrusting antenna" (PDF). 37th Joint Propulsion Conference and Exhibit. doi:10.2514/6.2001-3657. hdl:2060/20020009088.
- Podkletnov, E.; Nieminen, R. (December 1992). "A possibility of gravitational force shielding by bulk YBa2Cu3O7−x superconductor". Physica C: Superconductivity. 203 (3–4): 441–444. Bibcode:1992PhyC..203..441P. doi:10.1016/0921-4534(92)90055-H.
- Robertson, Tony; Lichford, Ron; Peters, Randall; Thompson, Byran; Rogers, Stephen L. (Jan 1, 2001). "Exploration of Anomalous Gravity Effects by rf-Pumped Magnetized High-T(c) Superconducting Oxides" (PDF). AIAA Joint Propulsion Conference; 8-11 Jul. 2001; Salt Lake City, UT; United States.
- Hathaway, G; Cleveland, B; Bao, Y (April 2003). "Gravity modification experiment using a rotating superconducting disk and radio frequency fields". Physica C: Superconductivity. 385 (4): 488–500. Bibcode:2003PhyC..385..488H. doi:10.1016/S0921-4534(02)02284-0.
- Woodward, James F. (October 1990). "A new experimental approach to Mach's principle and relativistic graviation". Foundations of Physics Letters. 3 (5): 497–506. Bibcode:1990FoPhL...3..497W. doi:10.1007/BF00665932.
- Woodward, James F. (October 1991). "Measurements of a Machian transient mass fluctuation". Foundations of Physics Letters. 4 (5): 407–423. Bibcode:1991FoPhL...4..407W. doi:10.1007/BF00691187.
- Cramer, John; Cassisi, Damon; Fey, Curran (Oct 1, 2004). "Tests of Mach's Principle with a mechanical oscillator" (PDF). 37th Joint Propulsion Conference and Exhibit. doi:10.2514/6.2001-3908. hdl:2060/20050080680.
- Ringermacher, Harry I. (1994). "An electrodynamic connection". Classical and Quantum Gravity. 11 (9): 2383–2394. Bibcode:1994CQGra..11.2383R. doi:10.1088/0264-9381/11/9/018. ISSN 0264-9381.
- Millis, Marc G. (September 1997). "Challenge to Create the Space Drive" (PDF). Journal of Propulsion and Power. 13 (5): 577–582. doi:10.2514/2.5215. hdl:2060/19980021277. Retrieved 8 February 2018.
- Corporation, Bonnier (2001-05-01). Popular Science May 2001. Retrieved 2012-01-25.
- Maclay, G. Jordan (17 April 2000). "Analysis of zero-point electromagnetic energy and Casimir forces in conducting rectangular cavities". Physical Review A. 61 (5): 052110. Bibcode:2000PhRvA..61e2110M. doi:10.1103/PhysRevA.61.052110.
- Maclay, G. Jordan; Forward, Robert L. (March 2004). "A Gedanken Spacecraft that Operates Using the Quantum Vacuum (Dynamic Casimir Effect)". Foundations of Physics. 34 (3): 477–500. arXiv:physics/0303108. Bibcode:2004FoPh...34..477M. doi:10.1023/B:FOOP.0000019624.51662.50.
- M. Millis and E. Davis, Frontiers of Propulsion Science, AIAA, Progress in Astronautics & Aeronautics Vol 227, 2009. ISBN 978-1563479564 ISBN 1563479567