Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum
David A. Brady · Harold G. White · Paul March · James T. Lawrence · Frank J. Davies
Abstract and summary · read the original at the source · none found
In one page
In August 2013 a NASA Johnson Space Center team — David Brady, Harold ’Sonny’ White, Paul March, James Lawrence and Frank Davies — spent eight days measuring two radio-frequency cavities on the Eagleworks torsion pendulum, a balance that resolves forces down to single-digit micronewtons. The cavities, designed by Cannae LLC, were driven at about 935 megahertz inside a closed stainless steel vacuum chamber held at ordinary air pressure. The pendulum moved: roughly 30 to 50 micronewtons, on both articles, including the one built as a null. Swapping the cavity for a plain radio-frequency load gave no force, which told the team the signal followed the cavity rather than the cabling. Their stated conclusion is careful and worth quoting exactly — the force is not attributable to any classical electromagnetic phenomenon, and may therefore be showing an interaction with the quantum vacuum virtual plasma. They named their own next steps too: automatic frequency control instead of a hand-tuned source, and independent verification at other facilities.
Why it matters hereThis is the measurement that put propellantless radio-frequency thrust on chapter 8’s table, made by a NASA group with a named apparatus and a stated force. It is also chapter 1’s evidence ladder in action, because the authors asked for exactly the thing that came next: Martin Tajmar’s SpaceDrive group at TU Dresden rebuilt the experiment on an instrument sensitive below a nanonewton, catalogued the thermal and cable artefacts that manufacture a convincing thrust signature, and found every reading inside the noise at or below the light-pressure limit. That replication is on this site at /library/stm-0d21110734, and the two sheets should be read together — the open regime both papers point at is the superconducting cavity, where the quality factor rises by orders of magnitude and nobody has yet looked.
What it claims
01An electric propulsion test article consisting primarily of a radio frequency resonant cavity excited at approximately 935 megahertz produced approximately 30 to 50 micronewtons of thrust, measured on a low-thrust torsion pendulum capable of detecting force at a single-digit micronewton level.Abstract, paragraph 2
Published and peer-reviewed02Thrust was observed on both test articles, even though one of them, the null article, was built without the internal physical modifications that were expected to produce thrust — a result the authors report rather than set aside.Abstract, paragraph 5
Published and peer-reviewed03Replacing the test article with a radio frequency load, and reversing the orientation of the article, were both run as controls, to verify that the force was not being generated by effects unassociated with the test article.Abstract, paragraph 2
Published and peer-reviewed04The team’s interpretation of the result is that the radio frequency resonant cavity thruster design is producing a force that is not attributable to any classical electromagnetic phenomenon and is therefore potentially demonstrating an interaction with the quantum vacuum virtual plasma.Abstract, final paragraph
What to watch05The campaign ran inside a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure, and the resonant frequency had to be held by hand throughout; the authors name automatic frequency control as the first thing to build before the next run.Abstract, paragraphs 2 and 6
What to watch06The paper closes by naming independent verification and validation at other test facilities as its own future test plan — the measurement that would settle the question, and the one Tajmar’s group at TU Dresden went on to make.Abstract, final sentence
What to watch
Read it · abstract
Abstract
This paper describes the eight-day August 2013 test campaign designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma. This paper will not address the physics of the quantum vacuum plasma thruster, but instead will describe the test integration, test operations, and the results obtained from the test campaign.
Approximately 30-50 micro-Newtons of thrust were recorded from an electric propulsion test article consisting primarily of a radio frequency (RF) resonant cavity excited at approximately 935 megahertz. Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level, within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure. Several different test configurations were used, including two different test articles as well as a reversal of the test article orientation. In addition, the test article was replaced by an RF load to verify that the force was not being generated by effects not associated with the test article. The two test articles were designed by Cannae LLC of Doylestown, Pennsylvania. The torsion pendulum was designed, built, and operated by Eagleworks Laboratories at the NASA Johnson Space Center of Houston, Texas.
Approximately six days of test integration were required, followed by two days of test operations, during which, technical issues were discovered and resolved. Integration of the two test articles and their supporting equipment was performed in an iterative fashion between the test bench and the vacuum chamber. In other words, the test article was tested on the bench, then moved to the chamber, then moved back as needed to resolve issues. Manual frequency control was required throughout the test. Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article).
Test data gathered includes torsion pendulum displacement measurements which are used to calculate generated force, still imagery in the visible spectrum to document the physical configuration, still imagery in the infrared spectrum to characterize the thermal environment, and video imagery. Post-test data includes static and animated graphics produced during RF resonant cavity characterization using the COMSOL Multiphysics software application. Excerpts from all of the above are included and discussed in this paper.
Lessons learned from test integration and operations include identification of the need to replace manual control of the resonant cavity target frequency with an automated frequency control capability. Future test plans include the development of an automatic frequency control circuit.
Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma. Future test plans include independent verification and validation at other test facilities.
The way in
https://doi.org/10.2514/6.2014-4029LICENCE CHECK. The version of record is a paper given at the 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cleveland, 28 to 30 July 2014, and copyright sits with the AIAA; no Creative Commons statement appears on the publisher record. NASA’s own copy, NTRS submission 20140006052 (report number JSC-CN-30345), is marked distribution PUBLIC with the determination GOV_PUBLIC_USE_PERMITTED rather than a US Government work, so it is not public domain either. The sheet therefore stays abstract-only. TEXT. Reproduced below is the extended abstract as NASA published it on the NTRS record, cleaned of page furniture; the full conference paper, with the pendulum traces, the infrared imagery and the COMSOL cavity models, is at the source.
How to cite it
David A. Brady, Harold G. White, Paul March, James T. Lawrence, Frank J. Davies (2014) Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum. doi:10.2514/6.2014-4029
Where it sits in the curriculum
Inertial mass reduction and transmedium craftThe evidence ladderInertia and gravity from the vacuumWhat the vacuum is