La propulsion nucléaire thermique ou nucléo-thermique est un mode de propulsion des fusées qui utilise un réacteur nucléaire pour chauffer un fluide propulsif. Celui-ci, comme dans le cas d'un moteur-fusée classique, est expulsé via une tuyère pour fournir la poussée qui propulse la fusée. Ce type de propulsion permet d'atteindre en théorie des vitesses d'éjection de gaz nettement plus élevées et donc un meilleur rendement que la propulsion chimique utilisée sur les lanceurs actuels.

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dbpedia-owl:abstract
  • La propulsion nucléaire thermique ou nucléo-thermique est un mode de propulsion des fusées qui utilise un réacteur nucléaire pour chauffer un fluide propulsif. Celui-ci, comme dans le cas d'un moteur-fusée classique, est expulsé via une tuyère pour fournir la poussée qui propulse la fusée. Ce type de propulsion permet d'atteindre en théorie des vitesses d'éjection de gaz nettement plus élevées et donc un meilleur rendement que la propulsion chimique utilisée sur les lanceurs actuels. Différentes architectures ont été étudiées depuis le début de l'ère spatiale du simple cœur solide (similaire à celui d'une centrale nucléaire) jusqu'aux concepts plus complexes mais plus efficaces tels que les cœurs gazeux. Bien qu'un prototype ait été testé au sol par les États-Unis (moteur NERVA), aucune fusée utilisant ce type de propulsion n'a encore jamais volé. Des recherches importantes sont encore nécessaires entre autres pour diminuer le rapport poids/poussée. Si elle est retenue, la propulsion nucléaire devra faire face à une partie de l'opinion publique fondamentalement hostile à tout lancement d'engins nucléaires. Aujourd'hui, le recours à la propulsion nucléaire n'est évoqué que dans le cadre du programme Constellation, pour des missions habitées hypothétiques vers Mars, à échéance éloignée (après 2037).
  • Rakietowy silnik nuklearny - silnik rakietowy w którym źródłem ciepła jest reaktor jądrowy. Ogrzany w reaktorze gaz rozprężając się w dyszy, nadaje pęd rakiecie. Przydatność tego silnika testowała NASA w programie NERVA.Zastosowanie tego silnika rozważał Robert Zubrin w swoim projekcie wyprawy na Marsa.zh:核脉冲推进
  • 핵열 로켓(영어: nuclear thermal rocket)은 원자료의 열을 이용하여 추진력을 얻는 로켓이다.기존의 산화제와 추진체를 연소시켜 하늘을 나는 기존의 로켓과 달리 원자로의 열로 수소가스를 팽창시켜서 팽창시킨 수소가스로 하늘을 난다. 최근 핵추진로켓에 대한 연구가 활발히 이루어지고 있다.
  • Я́дерный раке́тный дви́гатель (ЯРД) — разновидность ракетного двигателя, которая использует энергию деления или синтеза ядер для создания реактивной тяги. Бывают жидкостными (нагрев жидкого рабочего тела в нагревательной камере от ядерного реактора и вывод газа через сопло) и импульсно-взрывными (ядерные взрывы малой мощности при равном промежутке времени).Традиционный ЯРД в целом представляет собой конструкцию из нагревательной камеры с ядерным реактором, как источником тепла, системы подачи рабочего тела, и сопла. Рабочее тело (как правило — водород) — подаётся из бака в активную зону реактора, где, проходя через нагретые реакцией ядерного распада каналы, разогревается до высоких температур и затем выбрасывается через сопло, создавая реактивную тягу. Существуют различные конструкции ЯРД — твёрдофазный, жидкофазный и газофазный, соответственно агрегатному состоянию ядерного топлива в активной зоне реактора — твёрдое, расплав или высокотемпературный газ (либо даже плазма). ЯРД активно разрабатывались и испытывались в СССР (см. РД-0410) и США (см. NERVA) с середины 1950-х годов. Исследования ведутся и в настоящее время.
  • In un razzo termico nucleare un fluido di lavoro, di solito idrogeno liquido, viene riscaldato ad alta temperatura in un reattore nucleare e fatto espandere attraverso un ugello per generare la spinta. L'energia del reattore prodotta dalla fissione nucleare sostituisce quella generata dalle reazioni chimiche di un razzo a propulsione chimica.L'alta densità energetica del combustibile nucleare rispetto a quelli chimici permette una efficienza del propellente (misurata dalla velocità equivalente di efflusso) almeno doppia rispetto a quella dei propellenti chimici.A parità di spinta la massa di un razzo nucleare è circa la metà di un razzo convenzionale. Qualora venisse usato come stadio successivo al primo, permetterebbe di mandare in orbita un carico doppio o triplo rispetto agli stadi che sfruttano propellenti chimici.Per un certo periodo si era pensato di usare un razzo a propulsione nucleare come sostituto del motore J-2 usato nel secondo stadio del Saturn V per missioni dove erano richieste alte prestazioni, tipicamente missioni su Marte o con grandi carichi. "Rimorchiatori" nucleari erano stati progettati come parte del programma Space Shuttle in grado di trasferire carichi da un deposito di combustibile in orbita bassa verso orbite alte, la Luna ed altri pianeti. Robert Bussard propose il vettore monostadio "Aspen" che usava un razzo nucleare per la propulsione e idrogeno liquido come schermo parziale alla radiazione diffusa dei neutroni nella parte bassa dell'atmosfera. Anche l'Unione Sovietica studiò motori nucleari per le loro missioni sulla Luna, in particolare gli ultimi stadi dell'N1, sebbene il programma non avesse mai iniziato una fase di test avanzati come quelli condotti dagli Stati Uniti negli anni 60 in Nevada. Nonostante diverse prove effettuate al suolo con successo, nessun razzo nucleare venne mai lanciato dagli Stati Uniti prima che la corsa allo spazio finisse.Ad oggi, nessun razzo a propulsione nucleare ha mai volato, sebbene i NERVA NRX/EST e NRX/XE fossero stati costruiti e provati al suolo in configurazione di volo. Il Progetto Rover venne portato avanti dagli USA tra il 1955 al 1972 ed accumulò, con successo, oltre 17 ore di funzionamento. Il NERVA NRX/XE, considerato dalla Space Nuclear Propulsion Office (SNPO) l'ultimo sviluppo tecnologico necessario prima di procedere alla successiva fase di test in volo, accumulò due ore di funzionamento, inclusi 28 minuti alla massima potenza.Il razzo termico nucleare Russo RD-0410 è stato provato nel sito di ricerche nucleari vicino Semipalatinsk ed il suo impiego è stato previsto per la missione proposta Kurchatov Mars 1994 con equipaggio umano..
  • In a nuclear thermal rocket a working fluid, usually liquid hydrogen, is heated to a high temperature in a nuclear reactor, and then expands through a rocket nozzle to create thrust. In this kind of thermal rocket, the nuclear reactor's energy replaces the chemical energy of the propellant's reactive chemicals in a chemical rocket. The thermal heater / inert propellant paradigm as opposed to the reactive propellants of chemical rockets turns out to produce a superior effective exhaust velocity, and therefore a superior propulsive efficiency, with specific impulses on the order of twice that of chemical engines. The overall gross lift-off mass of a nuclear rocket is about half that of a chemical rocket, and hence when used as an upper stage it roughly doubles or triples the payload carried to orbit.[citation needed]A nuclear engine was considered for some time as a replacement for the J-2 used on the S-II and S-IVB stages on the Saturn V and Saturn I rockets. Originally "drop-in" replacements were considered for higher performance, but a larger replacement for the S-IVB stage was later studied for missions to Mars and other high-load profiles, known as the S-N. Nuclear thermal space "tugs" were planned as part of the Space Transportation System to take payloads from a propellant depot in Low Earth Orbit to higher orbits, the Moon, and other planets. Robert Bussard proposed the Single-Stage-To-Orbit "Aspen" vehicle using a nuclear thermal rocket for propulsion and liquid hydrogen propellant for partial shielding against neutron back scattering in the lower atmosphere. The Soviet Union studied nuclear engines for their own moon rockets, notably upper stages of the N-1, although they never entered an extensive testing program like the one the U.S. conducted throughout the 1960s at the Nevada Test Site. Despite many successful firings, American nuclear rockets did not fly before the space race ended.To date, no nuclear thermal rocket has flown, although the NERVA NRX/EST and NRX/XE were built and tested with flight design components. The highly successful U.S. Project Rover which ran from 1955 through 1972 accumulated over 17 hours of run time. The NERVA NRX/XE, judged by SNPO to be the last "technology development" reactor necessary before proceeding to flight prototypes, accumulated over 2 hours of run time, including 28 minutes at full power. The Russian nuclear thermal rocket RD-0410 was also claimed by the Soviets to have gone through a series of tests at the nuclear test site near Semipalatinsk.The United States tested twenty different sizes and designs during Project Rover and NASA's NERVA program from 1959 through 1972 at the Nevada Test Site, designated Kiwi, Phoebus, NRX/EST, NRX/XE, Pewee, Pewee 2 and the Nuclear Furnace, with progressively higher power densities culminating in the Pewee (1970) and Pewee 2. Tests of the improved Pewee 2 design were cancelled in 1970 in favor of the lower-cost Nuclear Furnace (NF-1), and the U.S. nuclear rocket program officially ended in spring of 1973. Current (2010) 25,000 pound-thrust reference designs (NERVA-Derivative Rockets, or NDRs) are based on the Pewee, and have specific impulses of 925 seconds.[citation needed]
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  • John S. Clark, Patrick McDaniel, Steven Howe, Ira Helms, Marland Stanley
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  • Nuclear Thermal Propulsion Technology: Results of an Interagency Panel in FY 1991
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  • NASA
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rdfs:comment
  • La propulsion nucléaire thermique ou nucléo-thermique est un mode de propulsion des fusées qui utilise un réacteur nucléaire pour chauffer un fluide propulsif. Celui-ci, comme dans le cas d'un moteur-fusée classique, est expulsé via une tuyère pour fournir la poussée qui propulse la fusée. Ce type de propulsion permet d'atteindre en théorie des vitesses d'éjection de gaz nettement plus élevées et donc un meilleur rendement que la propulsion chimique utilisée sur les lanceurs actuels.
  • Rakietowy silnik nuklearny - silnik rakietowy w którym źródłem ciepła jest reaktor jądrowy. Ogrzany w reaktorze gaz rozprężając się w dyszy, nadaje pęd rakiecie. Przydatność tego silnika testowała NASA w programie NERVA.Zastosowanie tego silnika rozważał Robert Zubrin w swoim projekcie wyprawy na Marsa.zh:核脉冲推进
  • 핵열 로켓(영어: nuclear thermal rocket)은 원자료의 열을 이용하여 추진력을 얻는 로켓이다.기존의 산화제와 추진체를 연소시켜 하늘을 나는 기존의 로켓과 달리 원자로의 열로 수소가스를 팽창시켜서 팽창시킨 수소가스로 하늘을 난다. 최근 핵추진로켓에 대한 연구가 활발히 이루어지고 있다.
  • Я́дерный раке́тный дви́гатель (ЯРД) — разновидность ракетного двигателя, которая использует энергию деления или синтеза ядер для создания реактивной тяги.
  • In un razzo termico nucleare un fluido di lavoro, di solito idrogeno liquido, viene riscaldato ad alta temperatura in un reattore nucleare e fatto espandere attraverso un ugello per generare la spinta.
  • In a nuclear thermal rocket a working fluid, usually liquid hydrogen, is heated to a high temperature in a nuclear reactor, and then expands through a rocket nozzle to create thrust. In this kind of thermal rocket, the nuclear reactor's energy replaces the chemical energy of the propellant's reactive chemicals in a chemical rocket.
rdfs:label
  • Propulsion nucléaire thermique
  • Nuclear thermal rocket
  • Razzo termico nucleare
  • Silnik nuklearny
  • Ядерный ракетный двигатель
  • 핵열 로켓
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