Martin Tajmar

Indium Field Emission Electric Propulsion Microthruster Experimental Characterization

Indium liquid metal ion sources have been flying for more than 10 years on a variety of spacecraft for spacecraft potential control and as the core element of mass spectrometers. Since 1995, a dedicated indium field emission electric propulsion (In-FEEP) thruster has been under development and recently passed a 2000-h endurance test. The In-FEEP thruster is a micropropulsion device for the 1-100 μN thrust range with low thrust noise and high resolution. The latest performance characteristics including direct thrust measurements and beam profiles are summarized. This information is very important for many upcoming missions that require ultraprecise drag-free control such as the Gravity Field and Steady-State Ocean Circulation Mission, LISA, Terrestrial Planet Finder/Darwin, or SMART-2.

Gravitomagnetic field of a rotating superconductor and of a rotating superfluid

Abstract The quantization of the extended canonical momentum in quantum materials including the effects of gravitational drag is applied successively to the case of a multiply connected rotating superconductor and superfluid. Experiments carried out on rotating superconductors, based on the quantization of the magnetic flux in rotating superconductors, lead to a disagreement with the theoretical predictions derived from the quantization of a canonical momentum without any gravitomagnetic term. To what extent can these discrepancies be attributed to the additional gravitomagnetic term of the extended canonical momentum? This is an open and important question. For the case of multiply connected rotating neutral superfluids, gravitational drag effects derived from rotating superconductor data appear to be hidden in the noise of present experiments according to a first rough analysis.

Measurement of Gravitomagnetic and Acceleration Fields around Rotating Superconductors

It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so‐called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper‐pairs. A similar field is predicted from Einstein’s general relativity theory and the presently observed amount of dark energy in the universe. An experimental facility was designed and built to measure small acceleration fields as well as gravitomagnetic fields in the vicinity of a fast rotating and accelerating superconductor in order to detect this so‐called gravitomagnetic London moment. This paper summarizes the efforts and results that have been obtained so far. Measurements with Niobium superconductors indeed show first signs which appear to be within a factor of 2 of our theoretical prediction. Possible error sources as well as the experimental difficulties are reviewed and discussed. If the gravitomagne...

Development and Test of a Miniature Hydrogen Peroxide Monopropellant Thruster

Analysis of present and future missions concluded that a miniaturised hydrogen peroxide monopropellant rocket engine is the optimum solution for the increasing demand for small and low cost propulsion systems for small satellites. The attractiveness of monopropellant thrusters is based on its operational and structural simplicity. Additionally, the utilization of hydrogen peroxide as propellant instead of hydrazine allows the reduction of the overall costs and would qualify such a system as a green propellant propulsion system. The present paper describes the development of a monopropellant thruster utilizing hydrogen peroxide and advanced catalyst beds. The utilization of a monolithic catalyst reduces the pressure loss across the catalyst bed significantly compared to formerly used pellet or gauze catalyst. This allows the use of relative lightweight tank and significantly minimizes the total weight. For Two different catalyst materials have been developed to achieve optimized decomposition. The present paper summarizes the experimental evaluation of the catalysts. Decomposition temperatures of up to 670°C and decomposition efficiencies up to 99% have been achieved. Up to 1.2 kg of hydrogen peroxide has been decomposed by a single catalyst, corresponding to about 1.25 hrs of operation. This is estimated to correspond in vacuum condition to a total delivered total impulse of 1600 Ns. A thrust balance was designed and built. Preliminary thrust measurements under atmospheric conditions have shown that the laboratory model can generate thrust in a range of at least 50 to 550 mN.

Extended analysis of gravitomagnetic fields in rotating superconductors and superfluids

Abstract Applying the Ginzburg–Landau theory including frame dragging effects to the case of a rotating superconductor, we were able to express the absolute value of the gravitomagnetic field involved to explain the Cooper pair mass anomaly previously reported by Tate. Although our analysis predicts large gravitomagnetic fields originating from superconductive gyroscopes, those should not affect the measurement of the Earth gravitomagnetic field by the Gravity Probe-B satellite. However, the hypothesis might be well suited to explain a mechanical momentum exchange phenomena reported for superfluid helium and a dragging force present in a rotating superconductor experiment.

Anomalous fiber optic gyroscope signals observed above spinning rings at low temperature

Precision fiber optic gyroscopes were mounted mechanically de-coupled above spinning rings inside a cryostat. Below a critical temperature (typically <30 K), the gyroscopes measure a significant deviation from their usual offset due to Earths rotation. This deviation is proportional to the applied angular ring velocity with maximum signals towards lower temperatures. The anomalous gyroscope signal is about 8 orders of magnitude smaller then the applied angular ring velocity, compensating about one third of the Earth rotation offset at an angular top speed of 420 rad/s. Moreover, our data shows a parity violation as the effect appears to be dominant for rotation against the Earths spin. No systematic effect was found to explain this effect including the magnetic environment, vibration and helium gas friction suggesting that our observation is a new low temperature phenomenon. Tests in various configurations suggest that the rotating low temperature helium may be the source of our anomalous signals.

Gravitomagnetic London moment and the graviton mass inside a superconductor

Using Proca electromagnetic and gravitoelectromagnetic equations the magnetic and gravitomagnetic properties of a rotating superconductor are respectively derived. Perfect diamagnetism, and the magnetic London moment are deduced from the photon mass in the superconductor. Similarly, it is shown that the conjecture proposed by the authors to resolve the Cooper-pair mass anomaly reported by Tate, can be explained by a graviton mass in the superconductor different with respect to its expected cosmological value.

Biefeld- Brown Effect: Misinterpretation of Corona Wind Phenomena

With its theoretical origins dating back to the early 1920s, the Biefeld‐Brown effect was believed to be responsible for the generation of thrust in capacitor configurations exposed to high voltage. This thrust was claimed to be unrelated to corona wind phenomena and to exist in vacuum. These claims, although only published in patents, survived until recent publications for very advanced propulsion concepts. Brown’s and similar work, as well as credible theoretical and experimental studies relating to the Biefeld‐Brown effect, are reviewed. Moreover, an experiment was carried out to investigate any thrust not related to corona discharges. No thrust was detected within the accuracy of the experimental setup. This puts new boundaries on any anomalous Biefeld‐Brown force. Measurements indicate that such anomalous force must be at least five orders of magnitude below corona wind phenomena and must have at least a two orders of magnitude higher power-to-thrust ratio compared to traditional electric propulsion thrusters. Hence, even if the effect exists, it would not be attractive for space propulsion. The obtained results suggest that corona wind effects were misinterpreted as a connection between gravity and electromagnetism.

Three-Dimensional Numerical Simulation of Field-Emission-Electric-Propulsion Neutralization

A three-dimensional full-particle-simulation model is developed for simulation of a e eld-emission-electricpropulsion (FEEP) thruster operation in an ambient plasma. Simulations are performed with ion-to-electron massratios close to actual values (mi/me =80,000)to resolve the basic characteristics of thepropellant ionsemitted from a FEEP thruster and their neutralization in an ambient plasma environment or by a thermionic neutralizer. The slit geometry allows a FEEP emitter to transmit reasonable values of emission current, even when no neutralization mechanism is present. However, to neutralize the FEEP beam, one must either operate the FEEP in an ambient plasma with a density comparable with the density of the FEEP beam ions and/or place a neutralizer at a location sufe cientlyfarfrom theFEEP emitter.Becausetheelectrice eldfrom theexposed high-voltageaccelerator dominates the neighboring region of FEEP thrusters, a neutralizer placed on the spacecraft surface beside the FEEP emitter will not provide effective neutralization.

ADVANCE OF MERCURY PERIHELION EXPLAINED BY COGRAVITY

The theory of General Relativity explaines the advance of Mercury perihelion using space curvature and the Schwartzschild metric. We demonstrate that this phenomena can also be interpreted due to the cogravitational field produced by the apparent motion of the Sun around Mercury giving exactly the same estimate as derived from the Schwartzschild metric in general relativity theory. This is a surprising result because the estimate from both theoretical approaches match exactly the measured value. The discussion and implications of this result is out of the scope of the present work.