Very dangerous.

Thank you Aref Wazwaz .

Your question does not specialize me sorry

In fact, it may have great benefits due to its ability to provide energy independence and not like solar cells, which despite their efficiency, save energy in orbits, and when the solar flow is high, here in nuclear energy sources they can save energy even in remote places about the sun, and therefore humans have been able to explore deep places in outer space... In addition to its small size, efficiency, long life and other features that make it more suitable and perhaps even necessary for some tasks in outer space... But of course, it should not forget to follow up and monitor the process of its management and the possibility that it has polluting effects on the environment, which may be reflected on the environment of the earth and the living creatures on it... My sincere gratitude to everyone.

Dear Profa. Manal Hadi Kanaan ,

As usual, your placements are always accurate.

Thank you so much for participating in the debate.

My deep respect and best regards,

Wiltgen

Its more suitable to resist the force of atmospheric fractions. Thus, the thrusters make spacecraft penetrating atmosphere.

Sorry, that's not it. It's for deep space!

Thanks a lot for a good question, dear friend, professor Filipe Wiltgen!

From the news in this area, which leaks into the media, it can be concluded that engines based on nuclear reactors already exist, at least in pilot versions or as prototypes. The inventions on which these engines are installed already have names. It will be a matter of technology to adapt them and install them on spaceships.

Best wishes!

With deep respect, Volodymyr Naumchuk

Dear friend Prof. Volodymyr Naumchuk ,

No doubt I believe that too!

Thank you for participating in this debate.

My deep respect and admiration,

Wiltgen

The use of space engines with nuclear reactors should take into account, on the one hand, the technical capabilities of this type of propulsion, the possible thrust performance at take-off, the possible achieved speeds of spacecraft after reaching orbit, etc., and, on the other hand, the safety of manned flights, the level of the risk of radioactive contamination of both the spacecraft and the atmosphere in the event of an accident, leakage of radioactive fuel, etc. A positive aspect of the use of space engines with nuclear reactors is the potentially low level of greenhouse gas emissions compared to traditional engines that burn fossil fuels. However, taking into account pro-environmental technological solutions, good solutions in this matter have been known for many years. For example, the space shuttles that NASA used at the end of the 20th century to explore space in the orbital sphere of the planet Earth, to launch certain satellites and other objects into orbit, for manned space flights, etc., were powered by engines in which the jet thrust energy was generated by the combustion of hydrogen with oxygen. Water vapor is released from these types of engines. Therefore, it is one of the most pro-environmental technical solutions for powering human-built motor vehicles.

Best regards,

Dariusz Prokopowicz

Dear Dariusz Prokopowicz,

As I said, conventional pro-environment solutions work well for "neighborhood" space exploration, not deep space.

There is no way to explore large distances in space in a timely manner with the solutions of traditional engines, not least because it would not be feasible and much less effective to carry so much fuel into space.

The risks exist, but as space itself already has a high radioactive risk given the cosmic ray emissions and the Sun's coronal mass jet, for spacecraft the risk of nuclear reactor is very low.

The biggest concern is the successful launch of ships with thrusters powered by nuclear reactors. Given that even a small amount of radioactive elements, if dispersed before going into orbit (an accident in which the nuclear reactor is destroyed), can cause great environmental damage and contamination.

Regards,

Wiltgen

Hi Prof. Filipe Wiltgen

Russians have reported, that they can do that:

2016:

https://www.wired.com/2016/03/russia-thinks-can-use-nukes-fly-mars-90-days-can-find-rubles/

2021:

https://www.businessinsider.com/russia-nuclear-powered-spacecraft-moon-venus-jupiter-2021-5

Russia’s Approach to Nuclear Power in Outer Space, (2021) Eurasia Daily Monitor Vol. 18 Issue: 92 by Pavel Luzin

https://jamestown.org/program/russias-approach-to-nuclear-power-in-outer-space

Best Regards.

Dear friend Prof. Pedro L. Contreras E. ,

As always, thank you very much for contribution and important links.

My deep respect and best wishes,

Wiltgen

You are most welcome, Prof. Filipe Wiltgen

For the last news in this regard, you can look at Nuclear Reactors & Radioisotopes for Space (* Updated May 2021).

* https://world-nuclear.org/information-library/non-power-nuclear-applications/transport/nuclear-reactors-for-space.aspx

Best Regards.

Prof. Pedro L. Contreras E. , thank you very much! My best regards, Wiltgen

From the analysis presented by F. Dyson, nuclear propulsion-based interstellar travel can be expected around 2150, provided that our civilization survives all the adverse effects of pollution and competition for resources. For the excellent analysis, please read:

https://people.eecs.berkeley.edu/~pister/publications/FamousPapers/DysonInterstellarOrion.pdf

Thank you Janusz Pudykiewicz .

”The biggest concern is the successful launch of ships with thrusters powered by nuclear reactors. Given that even a small amount of radioactive elements, if dispersed before going into orbit (an accident in which the nuclear reactor is destroyed), can cause great environmental damage and contamination”.

As far as the environmental pollution factors are concerned I would like to stress that nuclear propulsion is not designed for launches from the surface:

”NTP systems won’t be used on Earth. Instead, they’ll be launched into space by chemical rockets before they are turned on. NTP systems are not designed to produce the amount of thrust needed to leave the Earth's surface”

https://www.energy.gov/ne/articles/6-things-you-should-know-about-nuclear-thermal-propulsion

Janusz Pudykiewicz ,

Yeap! It's obvious!

We all know this, but if rocket explodes, obviously nuclear fuel will spread through atmosphere! That's what causes the contamination!

Nuclear reactors inside spaceships have deep space travel function!

Filipe Wiltgen

"Nuclear reactors inside spaceships have deep space travel function!!!"

Please read my comment carefully, this is exactly what I have stated.

As far as the exploding rockets are concerned the safety record from the past fifty years is very good, furthermore the amount of a fissionable material allocated to a single launch will be very limited, with the final reactor assembly performed on a low orbit.

In the past there was a lot of concern with the crashes of satellites carrying nuclear reactors and we have already significant expertise in the area of assessment of such events.

PS. Concerning the multiple use of exclamation point I would like to suggest the following commentary

https://www.theatlantic.com/technology/archive/2018/06/exclamation-point-inflation/563774/

Thanks Janusz Pudykiewicz .

Prof. Janusz Pudykiewicz Hi.

I guess that the Russian company Rosatom has already found no conventional nuclear reactors.

Something that could change the way, people look into the use of nuclear reactors for propulsion purposes.

https://en.wikipedia.org/wiki/Nyonoksa_radiation_accident

I read about it 2 years ago, now I just wanted to mention it.

Best Regards.

Thank you Prof. Pedro L. Contreras E. .

Dear Dr. Filipe Wiltgen , Thank you for this brilliant scientific & technical question.

I think there is one impediment. It is about radiation.

Also, I believe the technology is already there, and some countries have made enough progress on incorporating this technology in their war machinery (as pointed out by Dr. Pedro L. Contreras E. )

Apart from this, I dream, one day I would be driving my bike or car that runs on nuclear fuel.

Best wishes and regards

Yoganandan

Dear friend Prof. Yoganandan G ,

As always, thank you for your kindness and your participation in this debate.

I must confess that I have a lot of respect for nuclear energy, as all types of energy must be careful with its use. In this particular case, even with the fuel necessary for the transformation of energy.

I like use of nuclear reactors in spacecraft, however, as everything in engineering must be cautious and concerned about the protection of nuclear fuel reservoirs, whether during takeoff from Earth or during the trip.

My deep respect and best wishes,

Wiltgen

Dear Professor Pedro L. Contreras E.

Thank you for the information. When posting my comments I have considered a civilian solution such as described recently in the Popular Mechanics. It is created upon a safe design that is outlined in the following quote:

”Previously, the prospect of a nuclear-powered spacecraft exploding during takeoff and scattering dangerously radioactive materials across the U.S.—or worse, some other country—made nuclear propulsion untenable. However, modern designs rely on safer, low-enriched uranium, which cannot be converted into a weapon if it falls into the wrong hands.”

https://www.popularmechanics.com/military/research/a36110192/pentagon-nuclear-thermal-propulsion-rocket-plans/

This approach is in line with the visionary ideas of S. Ulam and F. Dyson from the 1950s. The deep space propulsion is facing different challenges that those in the military applications and it is much easier to manufacture.

With my Best regards.

Thanks.

Hi,

The queston is general, but any answer should be specific. For what particular mission is the use of nuclear generator so beneficial ? Long interplanetary missions. If the starting point for these missions is not within the atmosphere of the Earth, for instance if they were to start from the Moon, with inactive material having beeing lifted there and assembled and activated there, the risk is minimum. As there is no problem of aerodynamic, if the reactor is placed on a very long arm so that the radiations are negligeable for the crew, it also open possibilities. Of course, this implies to be able to perform the launch of the material from the Earth to the assembly platform, at an acceptable price, and be able to make the assembly there.

But I am not saying that this is the solution ! Just that it has to be studied case by case to balance benefits and risks, for the technology by itself is promising.

Dear Manola Romero ,

Yeap!

I agree, the fuel used in nuclear reactor must be well planned and carefully protected, until it can be used in space.

Thank you for participating in this debate.

Best Regards,

Wiltgen

Good Morning, Prof. Janusz Pudykiewicz, thank you for your reply.

I agree with your post about the civilian solution. However, we know that fields such as Nuclear, Atomic, and Radiative Hydrodynamics among others belong to the military.

They rule those fields. It should be that way unless the world wants to see mass destruction weapons falling in civilians or the wrong hands.

Best Regards.

Thank you Prof. Pedro L. Contreras E. .

Well, the chemical propulsion is very weak for effective flying within the Solar system and so far we do not know more energetic energy source than is nuclear power. However, the problem is more environmental than technical. The chemical launcher failure is not so rare, although it is well proven technology. What then about the nuclear propulsion ? The nuclear fuel should be transported to space (Moon?) very safe way by chemical rockets and only then used for propulsion.

Thank you Jan Balaz .

Hi;

Nuclear reactors used as thrusters for spacecraft offer a virtually unlimited energy density and a specific impulse twice as high as that of the most efficient traditional chemical systems. However, this technological choice may present a danger for the environment and the health of living beings on Earth. The problem has already arisen since nuclear reactors have equipped Russian and American satellites in the past. And the risk of seeing them disintegrate in the earth's atmosphere, releasing radioactive materials is very real.

With my best regards

Thank you ! : )

A beautiful & costly idea at the same time. Humans have worked hard to harm the environment on earth, so it was polluted by various pollutions. Then it moves to the oceans & polluted them, & went up to space & polluted the air. He was not satisfied with that, but man contaminated himself with the products of the alleged civilization. Playing with nuclear fuel is not easy, we have had enough of the problems of regular fuel. Thank you a lot dear friend dr. Filipe Wiltgen for this interesting question & for the valuable answers from respected colleagues.

Dear friend Prof. Shaker A.N. Al-Jadaan ,

As always, thank you very much for your participation in the debate.

I wish you well.

My deep respect and best wishes,

Wiltgen

Dear Dr. Wiltgen, My book "Incoming Asteroid! What Could We Do About it?" (Springer, 2013), summarises a project I chaired to answer the question, 'If we knew there was to be an impact in ten years' time, what could we do about it?' and the supplementary question 'What would we do?' For a threat which was credible and a challenge, but not too difficult at the current level of technology, we assumed an object with an orbit similar to Encke's Comet, but with perihelion much closer to Earth's orbit, first detected in a 'keyhole' flyby which would generate two opportunities to intercept it, at 3.3 year intervals. The first would allow interception on a standard Hohmann orbit, attainable with chemical fuels, but the second would require a more advanced propulsion system, and the NERVA nuclear-fission thermal rocket proved ideal for purpose, for several reasons. Details of the book can be found on my website, www.duncanlunan.com.

However a previous book, "Man and the Planets: the Resources of the Solar System" (Ashgrove Press, 1983) was based with permission on the terminology and reasoning of Dr. Krafft A. Ehricke's paper 'A Strategic Approach to Interplanetary Flight', (in in Roadman, Strughold and Mitchell, eds., Fourth International Symposium on Bioastronautics and the Exploration of Space, Aerospace Medical Division (AFSC), Brooks Air Force Base, Texas, 1968). Dr. Ehricke's analysis concluded that nuclear fission propulsion could provide initial crewed missions to Mars and Venus, but had no growth potential, and for any more advanced programme, more advanced systems would be needed.

I hope that's helpful!

With best wishes,

Duncan Lunan (Science Writer).

Duncan Lunan , thank you!

I am not sure how much people in the field is aware that the initial idea of the reactors that became known as Tokamaks was thought for space propulsion by the Russian researcher Sakharov. Anyway, nuclear engines have been in development for decades and I hope they will eventually become a reality. I have followed a completely non mainstream approach to nuclear reactions for some years now and Leif Holmlid relatively recently published the application of this approach to space propulsion that might be of interest for this discussion as it proposes a much more efficient and less dangerous nuclear drive basic concept.

Article Future interstellar rockets may use laser-induced annihilati...

Thanks.

: )

Each solution is good to be safe for man and nature.

This is a very interesting question. I fully agree and support the opinion of our distinguished colleagues Yoganandan G., Volodymyr Naumchuk. Thanks!

Nuclear reactors used as thrusters for spacecraft offer a virtually unlimited energy density and a specific impulse twice as high as that of the most efficient traditional chemical systems. However, this technological choice may present a danger for the environment and the health of living beings on Earth.

Unlike solar cells, nuclear power systems function independently of sunlight, which is necessary for deep space exploration. Nuclear-based systems can have less mass than solar cells of equivalent power, allowing more compact spacecraft that are easier to orient and direct in space.

Radioisotope Thermoelectric Generators (RTGs) have been the main power source for US space work since 1961. The high decay heat of Plutonium-238 (0.56 W/g) enables its use as an electricity source in the RTGs of spacecraft, satellites and navigation beacons.

Nuclear - Nuclear energy proves to be the most effective when attempting to make long distance missions in space. [2] Nuclear energy not only provides way more power than batteries, fuel cells, and photovoltaic, but it also is an enduring source of energy as it has a much longer lifespan.

There are multiple types of nuclear propulsion that could be used in space technology. With nuclear electric propulsion, thermal energy from a nuclear reactor is turned into electric energy that powers whatever type of electrical thruster or propulsion tech that a spacecraft uses.

A good idea, but it must be safe for people and nature.

Thank you all!

Happy Space Day, everyone!