Propellantless propulsion concepts based on electromagnetic waves like the EMDrive are claimed to be far superior with respect to the state of the art in spacecraft propulsion systems. Such devices ...consist of enclosed cavities with different geometric shapes that are injected with electromagnetic waves, producing unidirectional thrust without expelling propellant. Additional concepts emerged from theories like quantised inertia and involve laser-type EMDrives with optical cavity resonators and fiberoptic loops in the infrared spectrum. Claimed forces of these devices in the micronewton range are confronted with growing scepticism when basic conservation laws are applied. With cutting-edge measurement devices, we were able to characterize these concepts in a space-like environment with nanonewton resolution for thruster masses of up to 10 kg. Additionally, we enhanced our inverted double pendulum thrust balance with the ability to perform thrust measurements at cryogenic temperatures (65 K) to also operate a superconducting EMDrive that was claimed to have orders of magnitude higher thrust compared to classical resonators. In this paper, we present changes to each setup, based on criticism to our latest results, as well as thrust measurements of each device. Neither the EMDrive cavities nor the infrared laser resonators created a net-thrust above our balance noise. With the exception of the superconducting EMDrive, our data limits anomalous thrust below the threshold of classical propulsion with photon pressure for equivalent power-levels. Despite the enhancements made to each device, we did not detect any evidence in favour of the proposed theories.
•Very precise thrust measurements of various EMDrive-Type of thrusters.•First implementation of the ability to test high temperature superconductors on sub-μN precision thrust balances.•Identification of false-positive effects and setting of limits for anomalous thrusts on these type of proposed concepts.
The EMDrive is a proposed propellantless propulsion concept claiming to be many orders of magnitude more efficient than classical radiation pressure forces. It is based on microwaves, which are ...injected into a closed tapered cavity, producing a unidirectional thrust with values of at least 1 mN/kW. This was met with high scepticism going against basic conservation laws and classical mechanics. However, several tests and theories appeared in the literature supporting this concept. Measuring a thruster with a significant thermal and mechanical load as well as high electric currents, such as those required to operate a microwave amplifier, can create numerous artefacts that produce false-positive thrust values. After many iterations, we developed an inverted counterbalanced double pendulum thrust balance, where the thruster can be mounted on a bearing below its suspension point to eliminate most thermal drift effects. In addition, the EMDrive was self-powered by a battery-pack to remove undesired interactions due to feedthroughs. We found no thrust values within a wide frequency band including several resonance frequencies and different modes. Our data limit any anomalous thrust to below the force equivalent from classical radiation for a given amount of power. This provides strong limits to all proposed theories and rules out previous test results by at least two orders of magnitude.
Forces claimed by potential propellantless propulsion systems like the Mach-Effect-Thruster or the EMDrive are in the μN or even sub-μN range. In this paper, an automated thrust balance design ...capable of measuring forces of 100 nN for devices with a maximum mass of 10 kg is described to test these claims. The torsion balance features an electromagnetic calibration method, adjustable magnetic damping and tilt control as well as electromagnetic shielding. All onboard electronics can be controlled wirelessly via an infrared module for serial communication. Power is supplied to the balance using three separate liquid metal feedthroughs: one for voltages up to 500 V and frequencies up to 200 kHz, one for high voltage up to 30 kV DC or AC, and one for high frequency signals up to 3 GHz. The device can be rotated by 180° to measure three different thrust directions without breaking the vacuum and changing the setup in order to gain confidence and refute e.g. thermal drifts. The whole balance is controlled via a script language implemented in LabVIEW. We tested Mach-Effect-Thrusters provided by Woodward and our self-built model exploring higher frequencies and mixed-signals that are believed to create significantly higher forces. Also a magnetostrictive version was built and tested. For the EMDrive, several different frequencies and setups (with/without dielectric insert, flat/spherical end caps) were tested. Results of the tests performed between August and September 2018 are presented, but no final conclusions can be drawn.
•Thorough investigation of breakthrough propulsion concepts.•Thrust balance development to test EMDrive and Mach-Effect Thrusters.•Complementary experiments to test physics behind claims.•Education project towards interstellar spaceflight.
Since modern propulsion systems are insufficient for large-scale space exploration, a breakthrough in propulsion physics is required. Amongst different concepts, the EMDrive is a proposed device ...claiming to be more efficient in converting energy into propulsive forces than classical photon momentum exchange. It is based on a microwave resonator inside a tapered cavity. Recently, Taylor suggested using a laser instead of microwaves to boost thrust by many orders of magnitude due to the higher quality factor of optical resonators. His analysis was based on the theory of quantised inertia by McCulloch, who predicted that an asymmetry in mass surrounding the device and/or geometry is responsible for EMDrive-like forces. We put this concept to the test in a number of different configurations using various asymmetrical laser resonators, reflective cavities of different materials and size as well as fiber-optic loops, which were symmetrically and asymmetrically shaped. A dedicated high precision thrust balance was developed to test all these concepts with a sensitivity better than pure photon thrust, which is the force equivalent to the radiation pressure of a laser for the same power that is used to operate each individual devices. In summary, all devices showed no net thrust within our resolution at the Nanonewton range, meaning that any anomalous thrust must be below state-of-the-art propellantless propulsion. This puts strong limits on all proposed theories like quantised inertia by at least 4 orders of magnitude for the laboratory-scale geometries and power levels used with worst case assumptions for the theoretical predictions.
The controlled motion of a body in a central gravitational field without mass flow is considered. The possibility of moving the body in the radial direction from the center of attraction due to ...changes in the kinetic moment relative to the center of mass of the body is shown. A scheme for moving the body using a system of flywheels located in the same plane in near-circular orbits with different heights is proposed. The use of the spin of elementary particles is considered as flywheels. It is proved that using the spin of elementary particles with a Compton wavelength exceeding the distance to the attracting center is energetically more profitable than using the momentum of these particles to move the body. The calculation of motion using hypothetical particles (gravitons) is presented. A hypothesis has been put forward about the radiation of bodies during accelerated motion, which finds indirect confirmation in stellar dynamics and in an experiment with the fall of two bodies in a vacuum. The results can be used in experiments to search for elementary particles with low energy, explain cosmic phenomena and to develop transport objects on new physical principles.
The term “Breakthrough Propulsion Physics” comes from the NASA project by that name which examined non-rocket space drives, gravity control, and faster-than-light travel. The focus here is on space ...drives and the related unsolved physics of inertial frames. A “space drive” is a generic term encompassing any concept for using as-yet undiscovered physics to move a spacecraft instead of existing rockets, sails, or tethers. The collective state of the art spans mostly steps 1–3 of the scientific method: defining the problem, collecting data, and forming hypotheses. The key issues include (1) conservation of momentum, (2) absence of obvious reaction mass, and (3) the net-external thrusting requirement. Relevant open problems in physics include: (1) the sources and mechanisms of inertial frames, (2) coupling of gravitation to the other fundamental forces, and (3) the nature of the quantum vacuum. Rather than following the assumption that inertial frames are an immutable, intrinsic property of space, this paper revisits Mach's Principle, where it is posited that inertia is relative to the distant surrounding matter. This perspective allows conjectures that a space drive could impart reaction forces to that matter, via some as-yet undiscovered interaction with the inertial frame properties of space. Thought experiments are offered to begin a process to derive new hypotheses. It is unknown if this line of inquiry will be fruitful, but it is hoped that, by revisiting unsolved physics from a propulsion point of view, new insights will be gained.
•Explains relevance of unsolved inertial frame physics to space drive ambitions.•Updates space drive findings; benefits, challenges, approaches, and unsolved physics.•Comparatively lists type, status, issues, and references of 25 space drive inquiries.•Reviews inertial frame physics (Riemannian, optical-mechanical analogy, quantum).•Begins thought experiments to reassess inertial frames in context of space drives.
In an IAC13 paper the dynamic operation of a second generation superconducting EmDrive thruster was described. A mathematical model was developed and, in this paper, that model is used to extend the ...performance envelope of the technology. Three engine designs are evaluated. One is used as a lift engine for a launch vehicle, another as an orbital engine for the launcher and a third as the main engine for an interstellar probe.
The engines are based on YBCO superconducting cavities, and performance is predicted on the basis of the test data obtained in earlier experimental programmes. The Q values range from 8×107 to 2×108 and provide high values of specific force over a range of accelerations from 0.4m/s/s to 6m/s/s.
The launch vehicle is an “all-electric” single stage to orbit (SSTO) spaceplane, using a 900MHz, eight cavities, fully gimballed lift engine. A 1.5GHz fixed orbital engine provides the horizontal velocity component. Both engines use total loss liquid hydrogen cooling. Electrical power is provided by fuel cells, fed with gaseous hydrogen from the cooling system and liquid oxygen. A 2ton payload, externally mounted, can be flown to Low Earth Orbit in a time of 27min. The total launch mass is 10ton, with an airframe styled on the X37B, which allows aerobraking and a glide approach and landing.
The full potential of EmDrive propulsion for deep space missions is illustrated by the performance of the interstellar probe. A multi-cavity, fixed 500MHz engine is cooled by a closed cycle liquid nitrogen system. The refrigeration is carried out in a two stage reverse Brayton Cycle. Electrical power is provided by a 200kWe nuclear generator. The 9ton spacecraft, which includes a 1ton science payload, will achieve a terminal velocity of 0.67c, (where c is the speed of light), and cover a distance of 4 light years, over the 10 year propulsion period.
The work reported in this paper has resulted in design studies for two Demonstrator spacecrafts. The launcher will demonstrate the long-sought-for, low cost access to space, and also meet the mission requirements of the proposed DARPA XS-1 Spaceplane. The probe will enable the dream of an interstellar mission to be achieved within the next 20 years.
•The latest work on EmDrive propulsion for spacecraft is described.•YBCO superconducting cavities are incorporated into the thrusters.•Three engine types using multiple cavities are detailed.•A Single-Stage-To-Orbit spaceplane is described and mission parameters given.•An Interstellar Probe is described and mission parameters given.
Propellantless propulsion is believed to be the best option for interstellar travel. However, photon rockets or solar sails have thrusts so low that maybe only nano-scaled spacecraft may reach the ...next star within our lifetime using very high-power laser beams. Since 2012, a dedicated breakthrough propulsion physics group was founded at the Institute of Aerospace Engineering at TU Dresden to investigate different concepts based on non-classical/revolutionary propulsion ideas that claim to be at least an order of magnitude more efficient in producing thrust compared to photon rockets. Most of these schemes rely on modifying the inertial mass, which in turn could lead to a new propellantless propulsion method. Our intention is to develop an excellent research infrastructure to test new ideas and measure thrusts and/or artefacts with high confidence to determine if a concept works and if it does how to scale it up. At present, we are focusing on two possible revolutionary concepts: The EMDrive and the Mach-Effect Thruster. The first concept uses microwaves in a truncated cone-shaped cavity that is claimed to produce thrust. Although it is not clear on which theoretical basis this can work, several experimental tests have been reported in the literature, which warrants a closer examination. We are building several models of different sizes to understand scaling laws and the interaction with the test environment. The second concept is theoretically much better understood and is believed to generate mass fluctuations in a piezo-crystal stack that creates non-zero time-averaged thrusts. Apart from theoretical models, we are testing and building several such thrusters in novel setups to further investigate their thrust capability. In addition, we are performing side-experiments to investigate other experimental areas that may be promising for revolutionary propulsion. To improve our testing capabilities, several cutting-edge thrust balances are under development to compare thrust measurements in different measurement setups to gain confidence and to identify experimental artefacts.
•Thorough investigation of breakthrough propulsion concepts.•Thrust balance development to test EMDrive and Mach-Effect thrusters.•Complementary experiments to test physics behind claims.•Education project towards interstellar spaceflight.
Like the Planck–Einstein relation
E
=
ℏ
ω
, de Broglie’s
p
=
ħ
k
is another fundamental equation but the universal momentum formulation should be
p
=
ħ
β
. We propose the compelling evidence ...(vacuum Cherenkov radiation) and a new consequence which could lead to experimental checks is also worked out.
RF resonant cavity thrusters are a new concept in propulsion that has the advantage of comparatively large thrust, simple structure and high reliability. Their workings are unknown, but since their ...reproduction by multiple independent laboratories they show evidence of a potential revolution in the physical sciences, but also require more systematic study of both the phenomenon and the various claims in the production of the device. An EMDrive system comprises a frustum microwave resonance cavity, microwave source, and load. The microwave beam generated by microwave source was input into the frustum microwave resonator to form a pure standing wave and electromagnetic pressure gradient. Thus, along the axial direction of the frustum microwave resonator, net thrust is formed. Current, unverified, theories related to EMDrive predict a net radiation pressure that scales with the Q factor (amount of reflections inside the cavity before the radiation is absorbed) of the cavity, which has been observed. This article, based on classical electromagnetic theory, introduce a building of a propellantless microwave propulsion system work at 2.45GHz. The measurement of Q-factor of this resonance cavity and relative analyze had been completed follow the EMDrive theory.
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