Questions tagged [nuclear]

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

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27
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3answers
3k views

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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1answer
464 views

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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2answers
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Why does Curiosity use an RTG rather than solar (as Spirit and Opportunity do) for power?

Why did Curiosity choose to go with nuclear power? While solar panels have issues with Martian dust, this was a known factor before the 2004 Spirit and Opportunity mission. Why then did the 2004 ...
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1answer
257 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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2answers
717 views

How does the launch risk posed by plutonium compare to the launch risk posed by propellants?

For outer solar system exploration, virtually the only feasible power subsystem are Radioisotope thermoelectric generators (RTGs). These include plutonium, which may carry considerable risks (see ...
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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 ...
15
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1answer
2k views

What does it mean for a launcher to be 'nuclear-certified'?

This article says NASA has booked a nuclear-certified Atlas 5 for the launch of the Mars 2020 rover, and says this: currently, Atlas 5 is the only launch vehicle that holds a NASA certification ...
5
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1answer
603 views

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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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)?
15
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1answer
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How does the launch risk for a plutonium RTG and a uranium fission reactor compare?

I was looking at this answer that talks about how a good alternative to Radioisotope Thermoelectric Generators would be fission reactors. It makes a number of good points, but in the comment thread ...
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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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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 a nuclear detonation on Moon destroy life on Earth?

If a nuclear weapon is detonated on the moon it would launch debris into space. The debris would then fall to earth like asteroids. Would this impact wipe out life on Earth? In other words, are our ...
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2answers
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Nuclear Explosion in Space

It is possible to detonate a nuclear bomb in space, if possible then what will happen? In Armageddon movie we watched that, after discovering that an asteroid the size of Texas is going to impact ...
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1answer
735 views

Is it possible to use zinc powder as a NTR propellant?

The ISP of a propellant is important when mass is the limiting factor; however, that is not exactly the case when launching a rocket. For the first part of the flight, the density of the propellant is ...
27
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1answer
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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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2answers
742 views

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 ...
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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 ...
21
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1answer
777 views

Is there any ongoing research in nuclear pulse propulsion?

Nuclear pulse propulsion seemed to be quite actively researched up until the 1990's, with a few projects that saw some rather promising results (some that could theoretically reach over 4% light speed....
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2answers
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Dangers of launching a nuclear thermal rocket

Nuclear thermal rockets may have great benefits for Solar system exploration. But one consideration is that the launch of a nuclear engine from Earth's surface, as the payload on a chemical rocket, ...
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408 views

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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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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2answers
594 views

Tritium as energy source for probes?

There's this ingenious little hack video: "How to make tritium nuclear battery at home". The idea is very simple: "tritium keychain lights" - tubes with tritium and luminophor - placed between solar ...
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399 views

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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2answers
840 views

What happens to a spacecraft crashing into the Moon?

When planning a new architecture for lunar missions, one always faces the potential of nuclear thermal engines. Having a much higher $I_{sp}$, they offer a much higher propellant efficiency, causing a ...
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655 views

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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3answers
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Could a spacecraft take off from Earth using nuclear thermal rockets?

If enviromental concern was not taken into account, could you use a nuclear thermal rocket such as NERVA or Pewee to take off from Earth's surface into low Earth orbit? If not why? Is a launch ...
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147 views

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 ...
3
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1answer
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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1answer
255 views

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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1answer
96 views

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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1answer
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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 ...