Questions tagged [nuclear]

Questions regarding the use of nuclear devices in space exploration, e.g. to power or propel spacecraft.

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Temperature Differences on Satallites

Some satellites have radioisotope thermal generators. To convert thermal energy to electricity, a temperature difference is required (such as when using a thermocouple). How is a temperature ...
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How much is really known about those liquid metal droplets orbiting the Earth? (e.g. sizes, composition, orbits…) Are any actually tracked?

The question Orbit Guardians - bs, right? mentions a company proposing a smallsat that will capture then give a roughly 200 m/s retrograde "kick" to liquid metal NaK alloy droplets in LEO ...
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How could a fast powerful rover on Mars be powered electrically?

Background The rovers on Mars are slow and weak. If I am to believe what I read, MSL Curiosity only produces 1/6th of a horsepower electric effect, 125 watt. In order to perform tasks like deep ...
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Highest frequencies of EMPs in space

When a nuke detonates, an EMP at about 100 MHz followd. A pulsar on the other hand, has a comparatively low frequency, and while I know that this frequency depends on its spin and doesn't represent ...
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Cooling the nozzle extension of a nuclear salt water rocket (NSWR)

The nuclear salt water rocket(NSWR) uses a plutonium salt (at least to my understanding) dissolved in water as its fuel. The mixture is kept stable by filling the fuel tank with boron carbide, which ...
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Are nuclear thermal engine designs limited to about twice the Isp of existing chemical rocket engines? If so, why; what's the limiting factor?

Discussion below With Ultra Safe Nuclear engines and hydrogen propellant, how far to Mars could you get and still be able to return to Earth in an emergency? including a comment that suggests that the ...
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With Ultra Safe Nuclear engines and hydrogen propellant, how far to Mars could you get and still be able to return to Earth in an emergency?

The NPR news item (audio + transcript) Could Nuclear Power Aid In Travel To Mars? contains the following: VISHAL PATEL: If you want to go to Mars, nuclear is a smart choice. BRUMFIEL: Vishal Patel is ...
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Are power nuclear reactors (including advanced designs) really vastly less “aggressive” in design than NTR cores?

It is my understanding that solid-core nuclear thermal rocket reactors are extremely aggressive designs that operate at the limits of materials and have an incredibly high specific thermal power. Do ...
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Legality of nuclear debris field on the Moon?

A while ago, I asked about what happens to a nuclear engine that gets smashed into the Moon. While not conclusively answered, it's likely that the contaminated area is of significant size. But what ...
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What are the nuclear energy challenges specific to the moon?

What are moon specific hurdles to a fission reactor? low gravity no atmosphere Apparently it's more difficult to shed heat in a vacuum. Are some coolants more advantageous on the moon than others? ...
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Dispose Earth's nuclear wastes towards the sun [duplicate]

If rockets are reliable, can we throw our nuclear wastes towards the sun? The sun's gravity and it's internal energy will do the rest.
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78 views

Is “nuclear electrothermal” a recognized term for a specific technology?

Is the term "nuclear electrothermal" recognized as referring to a specific type of propulsion technology (specifically, the nuclear thermal rocket with heat engine and arcjet afterburner)?
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Options for (high-thrust) RCS with Isp beyond that of chemical?

There are a number of potential options for high-performance engines in the future: nuclear pulse propulsion, NTR, gas-core NTR, nuclear electrothermal, and potentially even fusion rockets. However, ...
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Why are RTGs different colors?

This is an image of the radioisotope thermoelectric generator (RTG) for Cassini: This one was for one left on the Moon: And this one is for the Multi-Mission RTG, used by Curiosity on Mars: One is ...
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How do large thermonuclear explosions on the ground affect satellites in LEO?

High altitude nuclear explosions will completely render electronic devices on the ground useless (unless protected, with lead coating for example). How are satellites affected by such explosions? ...
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535 views

Would capture of a uranium-rich asteroid open new possibilities?

It seems that energy production in space is a limiting factor. We can use photovoltaics, but they're of minimal value past Mars, and many interesting places (like the moon) have very long nights. The ...
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525 views

Could a thermal nuclear propulsion double as a nuclear reactor?

Nuclear thermal propulsion takes hydrogen and introduces it to enriched uranium that then heats up the gas and expels it to create thrust. Could you use also use the uranium to heat up water instead ...
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105 views

Using recent technology, how much electrical power could a nuclear reactor launchable by a low-level heavy-lift vehicle be developed to produce?

The main purpose behind asking this question is to ascertain the potential power-to-weight ratio of reactors built using modern-derivative technology (i.e. either Generation III derivatives or ...
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Can we re-fuel solid-core nuclear thermal rockets?

Most solid-core nuclear rocket designs seem to have a rather short fuel lifetime (and one that wastes most of the uranium or plutonium) due to the buildup of fission products (combined with the very ...
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What was the result of the propellant predictions in the last chapter of “Ignition!”?

In John D. Clarke's Ignition! (1972), the author spends the last chapter making predictions about the future of liquid rocket propellants. I thought these were very interesting, but I realize the book ...
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Why do nuclear rockets (e.g. NERVA) have such poor Thrust-to-Weight ratios?

Nuclear fission releases far more energy per kilogram of fuel than conventional hydrocarbon sources. However, proposed nuclear rocket engines like NERVA (https://en.wikipedia.org/wiki/NERVA), while ...
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Is the BBC's explanation of nuclear thermal electric propulsion wrong?

The new BBC News item New engine tech that could get us to Mars faster says: Once Orion has been connected to the transfer vehicle, a nuclear electric rocket would be used to get the crew capsule and ...
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Would a nuclear turbojet with a chemical afterburner be a suitable intermediate between a pure nuclear turbojet and a nuclear thermal rocket?

NOTE: This is not the place to question the fundamental viability of nuclear propulsion in aircraft and spacecraft. For context, in a spaceplane, the higher speeds you can attain under air-breathing ...
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Upper G acceleration limit for a small thorium nuclear reactor and electronics

For a small Orion nuclear pulse probe that is accelerating to 10% light speed: What would be the upper G force acceleration limit for electronics, a small thorium based nuclear reactor, pulse units ...
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Are DUMBO, TIMBERWIND, and other high-thrust NTRs realistically going to deliver on promises of very high thrust/weight?

Nuclear thermal rockets (NTRs) are notable as the most mature technology (the second-most-mature is Project Orion) to provide both high thrust and higher specific impulse than chemical rockets. But "...
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277 views

LANTR has been proposed; why not bilateral CHEMANTR?

Normal solid-core nuclear thermal rockets use a nuclear reactor to heat gas (almost always hydrogen, since higher molecular weights cause miserable performance) and expand it through a converging-...
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Would it be possible to send a nuclear bomb to Europa and make a hole in the ice of more than 11 km?

The idea is to carry an atomic bomb in an orbiter and throw it towards the surface, would it be plausible?
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Nuking the Sun?

We know that according to Wikipedia on Nuclear fusion: The Sun is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. In its core, the Sun fuses ...
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What would be the cost of a thorium reactors at the core of a large starship? [closed]

Thorium is a high power substance that can contains large amounts of energy in a small space. How much would it cost to install and maintain one on a large starship? As well as using solar panels, ...
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142 views

Have nuclear explosions in space produced any debris that was subsequently tracked, or did all of them completely self-vaporize?

This answer to Where in the solar system could a nuke be tested without anybody noticing? has got me wondering if nuclear explosions (nuclear tests) in space above Earth ever produced any chunks of ...
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What is the basis of the new Russian nuclear rocket propulsion?

The New York Times' Russia Confirms Radioactive Materials Were Involved in Deadly Blast discusses the potential nuclear aspects of the recent missile test and references several time the possibility ...
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Have nuclear reactors been used in space [duplicate]

Have nuclear reactors ever been used in space as a way for power, instead of solar panels? If not, have any plans for one ever been made?
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159 views

Can rocket engine like NERVA be used to get into low earth orbit or higher?

I have heard of nuclear propulsion, however I wonder that is it possible for it to launch into space, and if so, how much fuel would it need?
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Could a “nuclear turbo-jet” be built?

Being familiar with jet engines myself, I wonder whether a similar device could be built to provide high $I_{\text{sp}}$ and high thrust in vacuum and space. Using the tried-and-true turbojet formula ...
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259 views

Most recent launch of a nuclear reactor, and current barriers to launching the next one?

This question about Kilopower nuclear reactors got me thinking. Answer(s) to How many nuclear fission reactors have been launched into space? How many are still there? suggest that most nuclear ...
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Efficiency of a nuclear thermal rocket

I am trying to calculate the specific impulse and thrust of a nuclear thermal engine, given the thermal power of the reactor, the maximum working temperature and the propellant. I'm calculating the ...
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The problem of low level nuclear waste on Mars

How is it planned to handle low level nuclear waste on Mars produced by the use of Kilowpower reactors? Nothing is mentioned in the Wikipedia article about the resulting waste or spent fuel.
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What are the non-technical barriers to creating a practical nuclear propulsion system?

You can carve it however you want - it can be purely extra-orbital, it can be NERVA, it can be Orion. What are the specific legal and political barriers that prevent it from being implemented?
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For a hypothetical high-power nuclear spacecraft, where does the waste heat go?

It seems that all nuclear propulsion concepts extract fission energy as heat, and somehow convert a portion of that heat to energy in the desired form, such as electrical (e.g. to power an ion ...
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What happened to Kilopower generators?

Why are we still using solar power for spacecraft? Would it be possible to replace the giant solar arrays and batteries on spacecraft with Kilopower generators?
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Has there been any nuclear thermal rocket test program after NERVA?

Has NASA tested any nuclear thermal rocket engine after dropping the NERVA program? Is there any current ongoing mission to use nuclear power to make a rocket fly?
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Is there enough energy in a rocket nozzle for fission?

How much more energy does the rocket exhaust atom have to have to be before fission can occur to create more thrust? Which exhaust byproduct atom would be the easiest to split? I understand in ...
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Bombing the Moon: how much debris would there be in stable orbit?

If someone had actually nuked the Moon (e.g. here or Bombing Moon and Mars: What would it look like? ), what's the probability of some debris reaching a stable orbit around the Moon? This would not ...
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Are nuclear-powered engines the way to go for space exploration?

I often think about the future of humanity and how to achieve it. Despite criticism, the USA and USSR achieved significant scientific breakthroughs, such as: putting the first man in space landing ...
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What will be the best way to convert nuclear fusion energy into thrust for a rocket?

Best means maximum thrust, safest, easy to maintain. And it's not opinion based because I'm looking for a way that's theoretically feasible and may be practical in a few years. However, if you have an ...
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How much CO₂ could the wind through a tunnel within the deposit near the south pole of Mars sublimate?

Within the CO₂ deposit near the south pole of Mars, according to this article 3 subunits have been found with one having the top CO₂ layer of about 300 meters thick covered by a water ice layer with a ...
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Will the sinking of a nuclear reactor into the CO$_2$ deposit on Mars cause a huge explosion? [closed]

Within the CO$_2$ deposit near the south pole of Mars, according to this article 3 subunits have been found with one having a top CO$_2$ layer of about 300 meters thick covered by a water ice layer ...
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Why didn't the NERVA rockets use a higher neutron flux?

One of the big problems with NERVA was that the T/W ratio of the engine alone was hardly above one, making it impossible to use for getting into orbit. Since the power of a nuclear reactor is directly ...
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How similar are nuclear ramjets to nuclear thermal rockets?

Russia is currently developing nuclear powered cruise missiles. These presumably use nuclear ramjet propulsion in the same way that the US's Project Pluto would have. Is there enough similarity ...
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Orion Project (NPP) Pusher Plate computer models and survivability?

Does anyone know of any modern (1990's - present) computer modeling of the Orion pusher plate and its reaction/survivability to repeated plasma impacts? Regarding the 1950s/1960s Orion Project using ...