Questions tagged [nuclear]

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

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Solid Core Antimatter Engines: Do they have a point?

On the graph discussed in this question, I was surprised to see "antimatter" listed as one of the engine types... with a disappointing performance equal to solid-core nuclear thermal rockets....
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Nuclear or Solar power for satellites?

For satellites do they use solar or nuclear for the main power source? I do know that they have both but I do not know which is primary. for an example: Galileo, does it use solar or nuclear?
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What is the relationship (if any) between NASA's Kilopower project and its request for 40 kW reactor designs?

Gizmodo's NASA Wants to Put a Nuclear Reactor on the Moon begins NASA is teaming up with the U.S. Department of Energy’s Idaho National Laboratory to develop a non-solar power source on the Moon by ...
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Realistic cost of pulse units for nuclear pulse propulsion?

Nuclear pulse propulsion https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) was believed to be - by it proponents - far superior to chemical propulsion. Either because max. delta v you ...
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11 votes
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How much is 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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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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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 would be of significant size. But ...
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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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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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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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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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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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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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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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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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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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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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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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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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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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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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3 votes
1 answer
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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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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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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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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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1 vote
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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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5 votes
2 answers
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In what ways could a US-based commercial space company legally use nuclear power?

At the moment, commercial usage of space seems to be the next big 'thing' in space exploration. Much of this (tourism, commercial launch companies, etc) will likely use solar power or fuel cell ...
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How many nuclear fission reactors have been launched into space? How many are still there?

I remember @Hobbes's answer mentioning that the US has put one nuclear fission reactor in space, and that not much was known about Russia's program. The Bloomberg article NASA Is Bringing Back Cold ...
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8 votes
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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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Using Kilopower without shielding

The KRUSTY reactor (the first actual test under the Kilopower project) is shown in this image. As can be seen, about half of the mass is shielding. Suppose we were using the reactor on an umanned ...
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Is it true that nuclear rockets cut the journey to Mars in half?

The biggest challenge of our Mars journey is the journey time (9 months). Now I have seen news coming stating that atomic or nuclear rockets would cut the journey time in half. Is that right? When I ...
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What is known (or can be deduced with a high degree of certainty) about the distribution of uranium on Mars?

How difficult should we expect it to be to find minable uranium on Mars? What regions of Mars would we most expect to find it in? Is there anything we know about the geology of Mars that would present ...
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1 vote
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Would the EMP from atmospheric polar nuclear detonations on Mars felt by orbiting spacecraft be larger or smaller than (if it were) on Earth?

Gizmodo's Watch Elon Musk Describe Terraforming Mars to Stephen Colbert links to the video (shown below). Their second article Elon Musk Clarifies His Plan to "Nuke Mars" quotes Musk from a ...
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Can people be in orbit around Mars were they to blast the poles with Nuclear bombs? [closed]

IF we launched a series of nuclear strikes on the polar ice caps on Mars, would it affect anyone in orbit around mars (assuming we could have them in orbit around Mars in such circumstances)?
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