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Questions tagged [nuclear]

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

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216 views

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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1answer
194 views

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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1answer
157 views

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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1answer
178 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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1answer
217 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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1answer
95 views

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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1answer
116 views

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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0answers
36 views

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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1answer
206 views

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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1answer
121 views

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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2answers
180 views

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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1answer
256 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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1answer
231 views

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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2answers
216 views

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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3answers
4k views

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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1answer
105 views

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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0answers
102 views

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 SolarCity ...
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3answers
227 views

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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5answers
818 views

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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0answers
30 views

How can a nuclear spacecraft be in compliance with the Test Ban Treaty? [duplicate]

Specifically, a nuclear fusion rocket. And no pulse propulsion, because I know doing that will be very hard.
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0answers
84 views

Are fission thermal engines more expensive to develop than chemical engines?

Is there something inherent in the technology of a fission thermal rocket engine that makes it a more expensive endeavour than developing yet another chemical engine? For example because of the ...
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4answers
733 views

Mining lunar thorium for building nuclear rockets on the Moon

Has there been any research on what lunar in-situ processes would have to be developed to mine and process thorium to build nuclear thermal rockets on the Moon?
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1answer
292 views

Nuclear thermal rocket working fluid performance

After reading an announcement about NASA restarting NTR (nuclear thermal rocket) research I was wondering about how a working fluid would be chosen. For clarity, the working fluid is the gas that is ...
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0answers
132 views

Are there any designs for fusion engines with similar performance to a nuclear lightbulb?

Are there any fusion thrusters with a twr > 1 and an isp of a couple thousand seconds?
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0answers
171 views

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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2answers
435 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 ...
22
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1answer
991 views

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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3answers
264 views

What kinds of nuclear reactors are suitable for operations in space? (Beyond thermionic and RTG)

If we want a nuclear power plant in space with a capacity similar to that of a conventional water boiling turbine nuclear power plant on Earth today, what kinds of fundamental design changes would ...
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1answer
206 views

What “high-tech fission-powered mission” almost “killed” New Horizons?

When reading the Discover Magazine article How New Horizons Survived the 40-Year-Glitch and Made it to Pluto while writing this question I saw "...the new NASA administrator tried to kill New Horizons ...
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6answers
7k views

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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1answer
1k 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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2answers
194 views

Power requirements for solar electric interplanetary vehicle

I am interested in electric propulsion for manned interplanetary craft. There must be a lot of models for a craft able to travel to Mars, for instance. I am wondering what the power requirements seem ...
11
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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 ...
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1answer
581 views

Is terraforming mars with only 4 nuclear bombs/penetrators in 10 years possible as this paper says?

Abstract: "Four, 100kg fusion warheads, launched from a Mars orbiter, can throw into the air, enough dust to cover Mars' South Polar Cap, darken it, and cause it to sublime through increased solar ...
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1answer
1k views

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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2answers
445 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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2answers
2k views

Is it possible to covertly put an EMP weapon into an ISS-like orbit by masquerading it as a legitimate launch?

I'm writing a sci-fi novel and I need some clarification on some technical issues. An HEMP is an high-altitude EMP. A 400km high, high-yield nuclear explosion over Kansas could "switch off" all the ...
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1answer
646 views

How much thrust can a nuclear thermal rocket provide?

Which is the range of thrust (minimum and maximum) that a nuclear thermal rocket is estimated to produce? Knowing these values, which thrust to weight ratio would be able to produce?
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1answer
137 views

Could a micrometeorite bombardment in an IMIS craft result in reactor rupture leading to the crew becoming stranded?

Apparently, I am a bit indecisive regarding an event that could possibly occur within the context of reality regarding nuclear thermal rockets, and I was thinking: is this space disaster scenario ...
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4answers
957 views

Why is comet deflection so hard (and how does a fusion rocket help)?

I just read an article arguing that we need very fast rockets for the deflection of comets, since we will probably detect them just several months before impact. So we need to hurry in order to pick ...
11
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1answer
1k views

How does propellant flow work in a nuclear thermal rocket?

I assume a nuclear thermal rocket with a solid core first. The principle of operation seems simple enough: Bring your propellant close to your nuclear fuel, start a reaction and wait for some heat/...
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3answers
2k views

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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2answers
2k views

Would a nuclear propelled spaceship still need a storm shelter?

Assume you have a sophisticated nuclear (thermal or whatever comes to mind) propelled spaceship for your summer vacation on Mars. Half way there Houston calls and informs you about an inbound solar ...
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2answers
610 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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2answers
431 views

Detecting a Nuclear powered vehicle from outer space (at least 8 AU or further out) feasible?

I sometime see this quote in forum arguments against "Klingon/Romulan-style" cloaking in video games that tries to be close as possible to real-life. It is quite difficult to ascertain where the ...
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1answer
153 views

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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1answer
589 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 ...
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2answers
856 views

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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2answers
1k views

Could we detect a nuclear explosion near Proxima Centauri?

How big would a nuclear explosion in open space around 1 AU from Proxima Centauri have to be for it to be detectable with current technology? Assume best-case scenarios, such as we're specifically ...
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2answers
477 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 ...