Relativistic rocket: Dream and reality

Recent reports about propulsion without reaction mass have been met on one hand with enthusiasm and on the other hand with some doubts. Namely, closed metal cavities, when fueled with microwaves, have delivered thrust that could eventually maintain satellites on orbits using solar power. However, the measured thrust appears to be without any apparent exhaust. Thus the Law of Action-Reaction seems to have been violated. We consider the possibility that the exhaust is in a form that has so far escaped both experimental detection and theoretical attention. In the thruster’s cavity microwaves interfere with each other and invariably some photons will also end up co-propagating with opposite phases. At the destructive interference electromagnetic fields cancel. However, the photons themselves do not vanish for nothing but continue in propagation. These photon pairs without net electromagnetic field do not reflect back from the metal walls but escape from the resonator. By this action momentum is lost from the cavity which, according to the conservation of momentum, gives rise to an equal and opposite reaction. We examine theoretical corollaries and practical concerns that follow from the paired-photon conclusion.

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“…This insight could be useful in improving electromagnetic drives and help to examine other ideas of propellantless propulsion. [58][59][60] …”

Section: Discussionmentioning

confidence: 99%

On the exhaust of electromagnetic drive

Grahn¹,

Annila

Kolehmainen

2016

AIP Advances

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“…The only way to reduce the mass of an interstellar rocket able to achieve the same velocity is to increase the energy density of the fuel, and the only known potential fuel that exceeds nuclear fusion in this respect would be matter-antimatter annihilation (e.g. Forward 1982, Morgan 1982, Semyonov 2014. Such a capability is, of course, well beyond our immediate technological horizon but, should it ever prove practical, the very high energy density of antimatter would enable much less massive vehicles to achieve the same objective.…”

Section: Antimatter Rocketsmentioning

confidence: 99%

Direct Exoplanet Investigation Using Interstellar Space Probes

Crawford

2018

Handbook of Exoplanets

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Experience in exploring our own solar system has shown that direct investigation of planetary bodies using space probes invariably yields scientific knowledge not otherwise obtainable. In the case of exoplanets, such direct investigation may be required to confirm inferences made by astronomical observations, especially with regard to planetary interiors, surface processes, geological evolution, and possible biology. This will necessitate transporting sophisticated scientific instruments across interstellar space, and some proposed methods for achieving this with flight-times measured in decades are reviewed. It is concluded that, with the possible exception of very lightweight (and thus scientifically limited) probes accelerated to velocities of ~0.1c with powerful Earth-based lasers, achieving such a capability may have to wait until the development of a space-based civilization capable of leveraging the material and energy resources of the solar system.

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“…[3] Both concepts are hardly realizable technically and do not promise high propulsion efficiency due to relatively small cross-sections of electron-positron and protonantiproton annihilation resulting in lengthy "annihilation zone" and, as a consequence, in poor alignment of the propulsion jet. [1,4] Propulsion by a stream of high-energy ions [1,4] promises much better performance regarding the efficiency of annihilation energy conversion into propulsion energy and nearly ideal alignment of the propulsion jet of ions. The method is based on existing technology of linear ion accelerators which generate almost parallel beams of highenergy ions.…”

Section: Pros: Technology Advance and Social Spiritmentioning

confidence: 99%

“…2b and 2c as a function of proper velocity of the efflux ions in the rocket coordinate frame for two launching masses of 1000 and 10000 tons and for the reactor power of 10 12 watts (one terawatt), 10 13 watts, and 10 14 watts. The corresponding graphs of the rocket velocity as a function of proper time of flight andthe distance covered during the acceleration stage can be found in[1,4].…”

mentioning

confidence: 99%

Pros and cons of relativistic interstellar flight

Semyonov¹

2018

Acta Astronautica

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Two technological problems must be solved before daring to interstellar flight: fuel and propulsion. The highest energy-density 'fuel' is antimatter in its solid or liquid state and this fuel is likely to be our primary choice for multi-ton relativistic rockets. High-energy ion thrusters powered by annihilation reactors promise superior performance in comparison with direct propulsion by annihilation products. However the power generator onboard can significantly increase the rocket dry mass thus limiting the achievable speed. Two physical factors that stand against our dream of the stars are thermodynamics and radiation hazard. Heat-disposing radiator also increases the rocket dry mass. Interstellar gas turns into oncoming flux of hard ionizing radiation at a relativistic speed of the rocket while the oncoming relativistic interstellar dust grains can cause mechanical damage. Economy and psychology will play a decisive role in voting for or against the manned interstellar flights.

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Relativistic rocket: Dream and reality

Cited by 9 publications

References 41 publications

On the exhaust of electromagnetic drive

On the exhaust of electromagnetic drive

Direct Exoplanet Investigation Using Interstellar Space Probes

Pros and cons of relativistic interstellar flight

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