Nuclear Powered Spacecraft

[blackstar]

It's not though, there are more people today who do NOT believe the Moon Landings were real than every before and even more that believe the Earth is in fact flat and that space is fake. Couple that with the fact that far to many people don't understand how the politics and economics worked for the "Space Race" in general and the decision to stop going to the Moon in specific came about and the number of people, (including relevant politicians) gets scary fast.

Politics in general and the economics from those politics have kept us in Earth orbit without any major advances, (and some backsliding even) for half a century. From the looks of things that's not going to change any time soon.

Randy

You are not talking about technology here. You are talking about programs and goals. They are not the same thing. It is not "technological stagnation" that explains why the United States did not send humans to Mars, or develop a lunar base. It was a lack of political support for doing those things. That does not mean that "space technology" itself stagnated.

 

[Archibald]

Incidentally, there's a strong theory that the Cuban Missile Crisis was not without the hand of the Great Helmsman (Maojidong). It was he who proposed attacking the West first and ending imperialism.

There is even a pretty silly joke about it.
1968, the height of the Cultural Revolution. Mao brings its best nuclear scientists and generals together, because he has a great plan.
"Comrades, our nuclear program has advanced to such a sophistication, I consider possible to build ten suitcase nukes, give them to ten red guards, and send them destroying ten imperialist cities. Any objections ?"
All the scientists and generals just nod in approval.
Except one tiny general, bent under the weight of dozen of medals pinned to his chest and with thick spectacles. He timidly raise his hand, to Mao furor.
"Great Helmsman I can see a troubling issue that may endanger you great plan execution" the little guy said, shaking in terror.
"You dare ? tell me then. Is it a problem about the nukes ?"
"Oh no, great leader. As you say, we can make it."
Mao sighs, his anger flaring.
"Are you suggesting I may not found ten Red Guards fanatical enough to our great cause ?"
The tiny general visibly wants to vanish under the surface of the Earth
"No, not a problem either. One snap of your fingers and we will get a thousand of them !"
Mao anger erupts.
"So what, in the end ? will you tell me, or I throw you into a reeducation camp for the rest of your miserable life ?!!!"
"It is the suitcases, Great Helmsman.
"The... suitcases ? are you fucking kidding me ? What's wrong with... suitcases ? "
"Well, Great Leader... there is no way we can find ten suitcases in the entire country !"

 

[Alex_semenov1965]

«Ну, Великий Вождь... нам никак не найти и десяти чемоданов во всей стране!»

We in the USSR also loved to make fun of the Chinese. Incidentally, in the late 1970s, we were genuinely afraid of war with the Chinese. Somehow, we never feared war with the US! We were sure the Americans were as afraid of us as we were of them, and no one would attack anyone. But the real fear of the time was that the Chinese would attack us! We were afraid of their numbers! Not their bombs. Although, bombs too. I'm not talking about the government in the USSR, but about rumors and sentiments circulating among the people.

We also told jokes about how China launched the first artificial satellite and how 10 million Chinese people developed hernias.

But he who laughs last laughs best. China is now challenging the US in a new race to the moon. Right? And, frankly speaking, looking at the madness going on in the USA (yes, it’s no longer the country that we fools so unrequitedly loved), I would (for the thrill of it) bet on the Chinese!

 

[Alex_semenov1965]

And of course the movie "predicted" Three Miles Island by, what ? a week ? talk about a stupid coincidence.

So, you believe there were real secret forces that orchestrated all the events that led to the terrible radiophobia that's now engulfing modern Western society?
I know the Russian physicist Ostretsov, who (besides his good idea about relativistic nuclear technology) is known for his outrageous conspiracy theories. He claims the tsunami that engulfed Fukushima was deliberately created by an underwater nuclear explosion, and was intended to steal from Japan the remaining uranium that the US lacks.
Even if that's true, it's pointless to stage such incidents (no one will notice them if they're properly framed) without first stimulating public opinion, which requires UNDIVIDED control over the media. That is, we need to brainwash every journalist on the planet while they're still in university. I'd look for the enemies of humanity there!
The greatest enemy of cosmonautics and nuclear energy, in my opinion, is H.G. Wells. He's the master manipulator and instigator! The man whose science fiction novels I practically grew up on.


And yes, Leo Tolstoy as a mirror of the Russian Revolution is a reference to Pelevin's "Omon Ra." Wells was truly imitating Tolstoy in the title of his most famous novel, which aimed at world peace.
And yes, Leo Tolstoy's reflection in the "mirror" is no accident. It's a vulgar mockery of the entire 20th century (and our own, too).

If you're looking for the "root of evil," don't look for evil people. Look for the WRONG ideas that we all really like and that feed on our collective consciousness. People don't rule the world. Ideas rule the world

 

[Michel Van]

Thanks for this inside view of Politics
but we deviate from the Topic NUCLEAR POWERD SPACECRAFTS

View: https://www.youtube.com/watch?v=7GL9aKLYz4U&pp=ygUVbnVjbGVhciByb2NrZXQgZW5naW5l

 

[Alex_semenov1965]

Thanks for this inside view of Politics
but we deviate from the Topic NUCLEAR POWERD SPACECRAFTS

I get it. Good things in moderation. Don't overuse them!

Regarding nuclear vehicles IN GENERAL.

There's one nasty question. A thermal nuclear rocket must have very high power. Gigawatts. The RD-0410 has 200 MW of thermal power. And all this is released in a small volume. If the cooling stops, there's an explosion. The KIWI-TNT experience demonstrated this clearly. Who would fly such a dangerous engine?
Controlling such an engine is difficult, starting it is difficult, shutting it down is even more difficult. Regulation is also difficult.
Let's say we've managed to control the radiation during its operation. Gamma, neutrons... But even after shutdown, there is residual radiation. Especially gamma. How can we live with that?
And then there's residual heat! The same thing that has become the bane of all nuclear accidents.
A thermal nuclear rocket engine is an obvious, but very bad solution! It's no wonder the idea's originator was the mocking Richard Feynman! "Surely You're Joking, Mr. Feynman" (c)

Hydrogen, as a working fluid, is one of the worst substances to store. And a nuclear rocket truly requires a lot of it (much less for a chemical rocket, since the main propellant there is oxygen). With a nuclear rocket, you need a monstrously large tank!
And what's all this for? For (just) double the specific impulse (900-1200 s)! Thermal nuclear rockets pose so many problems that I wouldn't be surprised if such engines were forgotten one day, once and for all. They'd be written off as a crazy idea.
Although...
Perhaps it could find a very narrow niche. Say, propelling chunks of ice in the asteroid belt. Like a steam rocket?

Gas-phase nuclear rocket? Sorry, I don't believe in fairy tales. It's more likely that annihilation or controlled thermonuclear fusion will emerge than that someone will ride a gas-phase nuclear rocket engine with a decent exhaust velocity. This is, of course, just my opinion.

 

[Michel Van]

There's one nasty question. A thermal nuclear rocket must have very high power. Gigawatts. The RD-0410 has 200 MW of thermal power. And all this is released in a small volume. If the cooling stops, there's an explosion. The KIWI-TNT experience demonstrated this clearly. Who would fly such a dangerous engine?

it was cold war product, first design as ICBM engine by US and USSR (no Joke)
but Generals with brains in heads realised those ICBM were not what they needed.
so the design ended in nuclear testing for possible use in Space Program.

On paper it look great, you double the ISP you halve the Mass you launch to Moon or Mars
but reality it hab allot unsolved issue like losing parts of engine during operation.
in fact a NERVA engine had to got to critical operation in seconds to heat hydrogen,
Then need to cool the engine after MECO, what could take hours venting hydrogen true the NERVA reactor
and also restart of engine with radioactive waste products like Xenon & co was unsolved issue.

On Remass for Thermal Nuclear rockets is Hydrogen best choice, follow by Ammonia.
NO METHANE you don't want that highly reactive stuff in the Reactor,
it will choke the Cooling pipes with soot and you have flying Chernobyl !

All this let at Soviet side to Nuclear electric propulsion
while USA made political decision to build the space shuttle, what killed the NERVA program...

 

[Alex_semenov1965]

So, I haven't mentioned all the problems. A reactor is a simple thing. But any simplicity is worse than theft. When you delve into the details, it becomes clear that simplicity comes at a special, higher price. For example, I was shocked by the details in Neal Stephensen's novel Seveneves about the tiny radioactive particles from the reactor flying and hopping in zero gravity like fleas. When they entered the crew compartment, they eventually killed all the crew members one by one. It was impossible to catch them, no matter how hard they searched for them with a detector, so they simply ended up in the respiratory tract and inside each person. And then alpha radiation and... death with bloody diarrhea. Of course, this seems like a very exaggerated picture. And yet...At the same time, without atomic energy, there's no point in thinking about conquering space. That's undeniable. It's like the rise of humanity on Earth without mastering fire.

 

[publiusr]

So, I haven't mentioned all the problems. A reactor is a simple thing. But any simplicity is worse than theft.

Americium seems manageable

Americium-241 - Wikipedia

en.wikipedia.org

New Spacecraft Power System Passes First Test

In late 2024, the University signed an International Space Act Agreement with NASA to enable collaborative use of engineering design and laboratory resources at NASA Glenn, and the teams proceeded to test a revolutionary innovation that can positively impact space exploration.

www.techbriefs.com

The best part about Americium is that only 12 kg is needed for criticality

https://forum.cosmoquest.org/forum/science-and-space/science-and-technology/3750688-fission-fragment-reactors

In terms of deposition, 3D printing may help with spreading Americium as thin as Rubbia wants--this trick will also help:

https://phys.org/news/2025-12-jeweler-generation-nuclear-clocks.html

In 2008, a team of UCLA-led scientists proposed a scheme to use a laser to excite the nucleus of thorium atoms to realize extremely accurate, portable clocks. Last year, they realized this longstanding goal by bombarding thorium atoms embedded in specialized fluoride crystals with a laser. Now, they have found a way to dramatically simplify and strengthen the process by replacing the specialized crystals with thorium electroplated onto steel.

Anti-matter spiking

Antimatter Development Program

Printable PDF of this post. “Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist…

caseyhandmer.wordpress.com

Thorium craft

Thorium-Metal Alloys And Radioactive Jet Engines

Although metal alloys is not among the most exciting topics for most people, the moment you add the word ‘radioactive’, it does tend to get their attention. So too with the once fairly …

hackaday.com

Rad proofing solar

New Radiation-Proof Method Could Boost Space Solar Panels

What steps can be taken to improve and enhance the lifetime of space solar cells? This is what a recent study published in Joule hopes to address as an international team of researchers investigated new methods for improving both the lifetime and performance of space solar cells from the...

www.universetoday.com

Comet chasers

https://forum.cosmoquest.org/forum/cosmoquest-and-friends/universe-today/3751036-a-blueprint-for-visiting-an-interstellar-comet

https://forum.cosmoquest.org/forum/cosmoquest-and-friends/universe-today/3751028-how-to-catch-a-comet-that-hasn-t-been-discovered-yet

More

Nuclear Thermal Propulsion

nuclear thermal propulsion, NTP, iPhones, DARPA, SOS, AID, SKS, SMS, OSC, ORS, ISS, OPS, PPE, DSPS, UAV, LEO

www.deepspacepropulsion.org

https://phys.org/news/2026-01-nasa-advances-space-nuclear-propulsion.html

Pre-JIMO

1959 Electric Space Vehicle – The Unwanted Blog

An author's take on pulse Orions

Not in My Atmosphere! — The Pitfalls of Project Orion - Reactor

Can a terrible idea for spaceship propulsion inspire exciting new science fiction?

reactormag.com

Propulsion rankings

 

[Scott Kenny]

Nuclear -electric has tiny thrust

Combined Response

Yes, but the truth (and the good news) is that it's not a problem.
This was already known in 1952. Trajectories with accelerations of even 10^(-6)g make sense and offer advantages!
Thrust is a consequence. The cause is the specific power of the power plant. And the whole point is that if we increased the ship's specific power from 50 W/kg (already achievable) to 500 W/kg, we would reach Titan in a year. What can we say about Mars?
But even with around 100 W/kg (and this is undoubtedly achievable if we don't play dumb, as everyone loves to do these days), we'll see Titan in 2.3 years. Low thrust is not a problem on interplanetary routes. Here, nature has given us a concession that we have never learned to appreciate. For we, humanity, are stupid and capriciously spoiled.

Very true, for outer planets and/or deep space exploration.

Higher accelerations, even if they're still at the "just high enough to be noticeable to a human" level, work quite well in the inner solar system. For example, 0.015m/s/s will get you from Earth to Mars in about 90 days. 0.1m/s/s will get you to Mars in 35 days.

Those do include some pretty ludicrous delta-vee numbers, however. 0.1m/s/s Earth to Mars requires over 300,000 m/s delta-vee, and 0.015m/s/s requires over 120k m/s.

Nuclear-thermal has large thrust, but fails somewhere between the reactor (full of energy) and the hydrogen propellant (also full of energy)


It takes a 2700 K NERVA core to get 825 seconds of isp. Not enough to make a significant difference with chemical propulsion, and even less since Starship pioneering propellant-rich architecture.

Getting beyond 3000 K core can't be done with a solid one : the best materials are on their knees.

For example, the rather ludicrous Tory IIA ramjet (which might as well be a nuclear rocket) only got up to about 1725K and the Beryllium Oxide ceramic was white hot.

A [Pulsed Nuclear Thermal Rocket/Fission Fragment Rocket] PNTR / FFR bimodal drive would have unbelievable performance... high thrust PNTR inside gravity wells, lower thrust FFR for cruise between planets.

Agreed, if you can get people to not freak out when they hear the word Nuclear.

Radiphobia is rampant.

Regarding nuclear vehicles IN GENERAL.

There's one nasty question. A thermal nuclear rocket must have very high power. Gigawatts. The RD-0410 has 200 MW of thermal power. And all this is released in a small volume. If the cooling stops, there's an explosion. The KIWI-TNT experience demonstrated this clearly. Who would fly such a dangerous engine?
Controlling such an engine is difficult, starting it is difficult, shutting it down is even more difficult. Regulation is also difficult.
Let's say we've managed to control the radiation during its operation. Gamma, neutrons... But even after shutdown, there is residual radiation. Especially gamma. How can we live with that?
And then there's residual heat! The same thing that has become the bane of all nuclear accidents.

So you figure out how much heat you remove from the engine by continuing to run reaction mass through the reactor until it's safe enough to stop the flow, and include that calculation in your burn timing.

A thermal nuclear rocket engine is an obvious, but very bad solution! It's no wonder the idea's originator was the mocking Richard Feynman! "Surely You're Joking, Mr. Feynman" (c)
View attachment 793274
Hydrogen, as a working fluid, is one of the worst substances to store. And a nuclear rocket truly requires a lot of it (much less for a chemical rocket, since the main propellant there is oxygen). With a nuclear rocket, you need a monstrously large tank!
And what's all this for? For (just) double the specific impulse (900-1200 s)! Thermal nuclear rockets pose so many problems that I wouldn't be surprised if such engines were forgotten one day, once and for all. They'd be written off as a crazy idea.
Although...
Perhaps it could find a very narrow niche. Say, propelling chunks of ice in the asteroid belt. Like a steam rocket?

Water, Ammonia, or Methane are all "better" reaction masses than pure hydrogen for a nuclear thermal rocket. At least in terms of tank bulk. Water or Ammonia are better than Methane because at NTR temperatures Methane breaks down into hydrogen and carbon and that carbon builds up in the reactor. Chernobyl shows us what happens with carbon inside a nuclear reactor.

Water and Ammonia also break down into hydrogen and oxygen or nitrogen, but that doesn't coke up your reactor. The loose oxygen may be a little scary at NTR temperatures, but I think proper core design can mostly counter that issue.

Gas-phase nuclear rocket? Sorry, I don't believe in fairy tales. It's more likely that annihilation or controlled thermonuclear fusion will emerge than that someone will ride a gas-phase nuclear rocket engine with a decent exhaust velocity. This is, of course, just my opinion.

IMO the only viable gas-phase nuclear thermal rocket is fusion, not fission.

 

[Forest Green]

White House Order Underlines Space Force’s Counterspace Mission​

White House Order Underlines Space Force's Counterspace Mission

The Trump administration's new executive order on U.S. space superiority emphasizes the Space Force's counterspace mission.

www.airandspaceforces.com

Nuclear Propulsion​

Among the technology initiatives referenced in Trump’s order is a push for the U.S. to embrace nuclear power in space. The document names space nuclear propulsion as a key priority and commits to having a nuclear reactor ready to launch as part of a lunar mission by 2030.

The memo also directs the Assistant to the President for Science and Technology to issue guidance within 60 days on establishing a “National Initiative for American Space Nuclear Power.”

The order’s imperative for the U.S. to leverage space nuclear power is notable, Galbreath said. Thermal and electric nuclear propulsion system technology could offer a solution to the DOD’s satellite mobility needs as Space Command pushes for more maneuverable spacecraft.

The Defense Department has pursued several space nuclear power projects with varying success. A Defense Advanced Research Projects Agency effort to develop a nuclear thermal spacecraft engine through the Demonstration Rocket for Agile Cislunar Operations, or DRACO, was cut short earlier this year. A separate Air Force Research Laboratory program—Joint Emergent Technology Supplying On-orbit Nuclear Power, or JETSON—is focused on nuclear electric propulsion for space applications.

 

[moin1900]

"Maintenance Station Envisioned for Nuclear-Powered Spacecraft" -
1962 - Westinghouse Electric Corp's Astronuclear Laboratory - Artist's concept
https://www.aerospaceprojectsreview.com/blog/?p=3557

 

[Alex_semenov1965]

"Maintenance Station Envisioned for Nuclear-Powered Spacecraft" -
1962 - Westinghouse Electric Corp's Astronuclear Laboratory - Artist's concept
https://www.aerospaceprojectsreview.com/blog/?p=3557

This is interesting. I love looking at projects from the 50s and 60s. Unlike later "designs," they all usually had common sense in engineering. But I'm afraid this picture isn't as well-thought-out as others from the same era.

 

[Nik]

Those cooling fins...
I remember multiple notions for replacing such fixed arrays, often invoking dust or beads, torrents of the stuff streaming between 'hot' and 'cold' end, caught, returned...

Reminded me of the steam 'Road Engines' my father described, which had radiator / condenser arrays on their roof. This facility *some-what* extended their range between 'watering holes'.
It also increased their 'Dead Weight', and rather raised their 'Centre of Gravity'...

FWIW, meson-catalysed fusion may yet trump all but the most niche fission reactors...

 

[Sferrin]

The comments here are especially valuable and revealing. It seems everyone has had their say. From flat-Earth theorists (Kubrick filmed everything on a soundstage) to those who remember what NERVA is. But the overall tone is one of extreme skepticism.
The main question: why is nuclear power being implemented in space so slowly and with such difficulty? Although, one could also ask a more general question: why are space technologies "developing" so slowly? It's safe to say they've been stagnating for half a century. Entire generations have grown up who can be shown projects from the 1950s and 1960s, and they won't believe that their grandfathers and even great-grandfathers invented them!

Because the voting public has been told to be terrified of anything nuclear. It's tough enough getting an RTG up, without some activist crawling out from under their rock. A "nuclear rocket that could Three Mile Island / Chernobyl on the pad"? Good luck.

 

[Michel Van]

This is interesting. I love looking at projects from the 50s and 60s.

here some of them in our Forum

TRW - Solar Electric Multi Mission Spacecraft (1970)​

One take on a 1963 Manned Mars Mission Concept​

General Electric Mars Mission Study July 19, 1967​

 

[blackstar]

This is interesting. I love looking at projects from the 50s and 60s. Unlike later "designs," they all usually had common sense in engineering. But I'm afraid this picture isn't as well-thought-out as others from the same era.
View attachment 799967

The one at lower right is from the Stuhlinger Mars mission. That was featured in the Disney documentary from the mid-1950s.

 

[Michel Van]

But I'm afraid this picture isn't as well-thought-out as others from the same era.

clock wise:
1 Artist Sol Dember conception of nuclear-electric ion spacecraft - somewhere in 1960s
2 Lewis Research Center - May 1965
3 USAF SPUR Spacecraft Concept by Airresarch (the Garrett Corporation) - 1963 ?
4 Stuhlinger Mars mission - 1957

Source

Atomic Rockets - Atomic Rockets

www.projectrho.com

https://www.secretprojects.co.uk/threads/usaf-interplanetary-spacecraft-concept-using-spur.8399/

 

[publiusr]

On Neptunium

https://techxplore.com/news/2026-02-neptunium-yields-plutonium-insights-space.html

Thermal decomposition of neptunyl ammonium nitrate: mechanistic insights and structural characterization of the Np2O5 intermediate phase

Neptunium (Np) possesses a rich and unique chemistry that often diverges from other actinide elements yet remains relatively underexplored compared with the other light actinides. A resurgence of interest in Np has been spurred by the application of 237Np for plutonium-238 (238Pu) production for...

xlink.rsc.org

https://phys.org/news/2026-02-extraterrestrial-strategy-energy-dominance-space.html

To the solar foci

https://arxiv.org/pdf/2602.04198

https://forum.cosmoquest.org/forum/cosmoquest-and-friends/universe-today/3752359-the-radical-propulsion-needed-to-catch-the-solar-gravitational-lens

Propulsion Options for the Solar Gravitational Lens Mission | Centauri Dreams

 

[Forest Green]

The space nuclear power bottleneck — and how to fix it​

The space nuclear power bottleneck — and how to fix it

The space nuclear power bottleneck — and how to fix it

spacenews.com

 

[publiusr]

I see Eager Space is sliming NTRs

View: https://www.youtube.com/watch?v=e8pL44Z-81Y


You know, those can generate electricity too--like for BNTEP

https://ntrs.nasa.gov/api/citations/20140017159/downloads/20140017159.pdf

https://ntrs.nasa.gov/api/citations/20140009587/downloads/20140009587.pdf

NTR
file:///C:/Users/piw10/Downloads/6502-Article%20Text-43376-1-10-20240807.pdf

https://ntrs.nasa.gov/api/citations/20140017461/downloads/20140017461.pdf

https://ntrs.nasa.gov/api/citations/20120012928/downloads/20120012928.pdf

https://ntrs.nasa.gov/api/citations/20040086714/downloads/20040086714.pdf

NEP

https://ntrs.nasa.gov/api/citations/20030067855/downloads/20030067855.pdf

Small

https://www.sciencedirect.com/science/article/pii/S1738573315001540

If there is anything-anything--to this latest scribbling

https://twitter.com/x/status/2031165988486722027

New Paper by Sonny White

New Paper by Sonny White

forum.nasaspaceflight.com

---=-Then you need electricity from something with better energy density than Musk's methane.

Ion engines, quantized inertia--whatever.

Nukes! Learn to quit worrying and love them.

 

[Seragina]

My bet has always been on photonic for the far future (for power in the classic sense)

If there is anything-anything--to this latest scribbling

https://twitter.com/x/status/2031165988486722027

New Paper by Sonny White

New Paper by Sonny White

forum.nasaspaceflight.com

It seems here I can build a single atom reactor with a laser...

 

[publiusr]

I know...right next to Mallet's time machine

View: https://m.youtube.com/watch?v=wxc82VmVLyM&pp=0gcJCcMKAYcqIYzv


At any rate...whether it's Scotty's unobtainium, a laser to zap rocks with, or messages home...they are going to need electricity.

Eager space hates SLS and hydrogen. Since NTRs work best on hydrogen-naturally he dumps on that too.

 

[Brett Davidson]

The laws of physics and engineering are the same everywhere, I've said. Looking at the render of Space Reactor 1 Freedom with the repurposed Gateway propulsion module and seeing that NASA will be favouring nuclear-electric over nuclear-thermal, a crewed Mars spacecraft seems likely to be a scaled-up version of the concept.

This report went into great detail back in 2014.

Human Exploration of Mars Design Reference Architecture 5.0, Addendum #2 - NASA Technical Reports Server (NTRS)

This report serves as the second Addendum to NASA-SP-2009-566, "Human Exploration of Mars Design Reference Architecture 5.0." The data and descriptions contained within this Addendum capture some of the key assessments and studies produced since publication of the original document...

ntrs.nasa.gov

It's a big document - nearly 70 MB.

A few illustrations of SR-1 and the crewed spacecraft. One interesting detail in the crewed design is the orientation of the thrusters perpendicular to the long axis. Since thrust is so low, mechanical stresses wouldn't be a major concern.

 

[publiusr]

From next-big

Four Times the Ion Drive Thrust With 20+KW Nuclear Reactor for 2028 NASA Mars Mission | NextBigFuture.com

The NASA planned 2028 nuclear powered ion drive spacecraft, SR-1 Freedom will have a 20 kilowatt nuclear reactor. SR-1 Freedom will use 20-plus kilowatt

www.nextbigfuture.com

Still more compact than some of the solar electric Mars ships--those looked between Gateway and ISS...

https://ntrs.nasa.gov/api/citations/20140017760/downloads/20140017760.pdf

https://www.labroots.com/trending/space/892/a-manned-ship-with-solar-electric-propulsion/amp

Pulse Orion

https://twitter.com/x/status/2044795594007331297

View: https://x.com/Mangeon4/status/2044795594007331297

 

[publiusr]

Let me float this out...
Anyone look at NSWR gun launch? Lunar launch only...

The great power and the weaker gravity allows large, heavy objects----payload protected by sabot.

 

[Brett Davidson]

A look back at the Jupiter Icy Moons Orbiter by Dwayne Day.

The Space Review: Prometheus bound: The legacy of the Jupiter Icy Moons Orbiter

Final report after the programme's cancellation.

https://dataverse.jpl.nasa.gov/api/access/datafile/18048?gbrecs=true

 

[publiusr]

Humans wouldn't be it the shot---this isn't a thunderwell. The NSWR would launch in place of a mass driver. No sudden shock of atmosphere. Sabot falls away, and the heavy, unmanned object can be taxi'd to with a capsule atop FH

 

[blackstar]

The laws of physics and engineering are the same everywhere, I've said. Looking at the render of Space Reactor 1 Freedom with the repurposed Gateway propulsion module and seeing that NASA will be favouring nuclear-electric over nuclear-thermal, a crewed Mars spacecraft seems likely to be a scaled-up version of the concept.

This project will be canceled. Frankensat proposals never work very well, and this project combines several different hardware concepts that were not designed from the ground up to go together. That will inevitably require redesign and delays and cost increases. Push it out too many years, and future politicians will kill it as a dumb program that is just eating money.

But there are other problems too. Who wants what this provides? Nuclear electric propulsion was not on anybody's wish list. The planetary science community doesn't want it. They want stuff that they can use in the near-term. If you look at their list of high-priority planetary science missions, none of them will benefit from this technology. They cannot use the propulsion, and the helicopters won't do much useful science. If somebody needs a Honda so that they can drive to work, promising them a Mercedes-Benz in ten years won't meet their needs.

 

[Brett Davidson]

A Uranus orbiter and probe has been identified as a priority and if conventionally-propelled, it will take over a decade to get there, so things like that are more than short term (not likely with current policy of course, but that can change in a later administration). Nuclear-electric could cut years off the flight and make deceleration and orbital insertion much easier, so the technology is attractive in some ways.

For getting a crew to Mars, nuclear electric promises to cut transit time substantially, reducing the radiation exposure to the crew. Both electric and thermal have been pushed for this reason. It's not so essential for robots or cargo.

Helicopters can do useful science - that's the rationale behind Dragonfly. That's a single big one but individual experiments can be distributed around small ones. The mission concept is still at a basic stage anyway, so we can't be sure what it will be in details like that.

SR-1 looks most useful as a technology demonstrator for a future crewed ship - but considering current focus on the Moon (including Musk's shift), a crewed Mars mission may well be pushed into the late 30's or early 40's anyway.

Frankensats can work - the best is the enemy of the good enough (not to mention affordable). A good many successful craft have been made from repurposed or derived hardware. Skylab was a mash-up of a Saturn 3rd stage and a lunar module. The Nancy Grace Roman observatory uses a repurposed spysat mirror.

Looking at JIMO, that's where the SR-1 design faces hurdles. First, JIMO's projected budget was huge - more than twice what Webb's actually turned out to be and that was a crazy overrun. Who knows what JIMO would have cost? Too much, whatever it would have been.

A second major problem from a scientific standpoint is vibration. Stirling engines were proposed for JIMO to convert thermal energy to electricity and they would have vibrated - but a genuinely useful scientific platform requires extreme stability for many different types of experiments - long-exposure optical, gravitational field mapping and so on. One reason why some scientists dislike the money going into the ISS is that it has monkeys bouncing around inside it, making it shake.

My guess then is that Jared Isaacman is trying to get a demonstrator for a future crewed interplanetary transport, but as it exists separately from the lunar exploration ecosystem, it may well be sacrificed by this administration or the next.

Looking long term, maybe for outer planet and Kuiper belt exploration, the probe and nuclear propulsion module could be separated upon arrival, maybe even with the propulsion module sent on a slow return for eventual recovery back in Earth orbit. If you have a look at the Mars Reference Mission report I've linked above, the reactor and hab/thruster modules are launched separately and both have repurposed Shuttle OMS engines for Mars orbit insertion - meaning that they separate for that manoeuvre. It seems unnecessarily complex in that instance, but the principle is there to see. OTOH, laser sail techniques taken from the recently abandoned Breakthrough Starshot project might be better,,,

 

[blackstar]

A Uranus orbiter and probe has been identified as a priority and if conventionally-propelled, it will take over a decade to get there, so things like that are more than short term (not likely with current policy of course, but that can change in a later administration). Nuclear-electric could cut years off the flight and make deceleration and orbital insertion much easier, so the technology is attractive in some ways.

For getting a crew to Mars, nuclear electric promises to cut transit time substantially, reducing the radiation exposure to the crew. Both electric and thermal have been pushed for this reason. It's not so essential for robots or cargo.

Helicopters can do useful science - that's the rationale behind Dragonfly. That's a single big one but individual experiments can be distributed around small ones. The mission concept is still at a basic stage anyway, so we can't be sure what it will be in details like that.

SR-1 looks most useful as a technology demonstrator for a future crewed ship - but considering current focus on the Moon (including Musk's shift), a crewed Mars mission may well be pushed into the late 30's or early 40's anyway.

Frankensats can work - the best is the enemy of the good enough (not to mention affordable). A good many successful craft have been made from repurposed or derived hardware. Skylab was a mash-up of a Saturn 3rd stage and a lunar module. The Nancy Grace Roman observatory uses a repurposed spysat mirror.

Looking at JIMO, that's where the SR-1 design faces hurdles. First, JIMO's projected budget was huge - more than twice what Webb's actually turned out to be and that was a crazy overrun. Who knows what JIMO would have cost? Too much, whatever it would have been.

A second major problem from a scientific standpoint is vibration. Stirling engines were proposed for JIMO to convert thermal energy to electricity and they would have vibrated - but a genuinely useful scientific platform requires extreme stability for many different types of experiments - long-exposure optical, gravitational field mapping and so on. One reason why some scientists dislike the money going into the ISS is that it has monkeys bouncing around inside it, making it shake.

My guess then is that Jared Isaacman is trying to get a demonstrator for a future crewed interplanetary transport, but as it exists separately from the lunar exploration ecosystem, it may well be sacrificed by this administration or the next.

Looking long term, maybe for outer planet and Kuiper belt exploration, the probe and nuclear propulsion module could be separated upon arrival, maybe even with the propulsion module sent on a slow return for eventual recovery back in Earth orbit. If you have a look at the Mars Reference Mission report I've linked above, the reactor and hab/thruster modules are launched separately and both have repurposed Shuttle OMS engines for Mars orbit insertion - meaning that they separate for that manoeuvre. It seems unnecessarily complex in that instance, but the principle is there to see. OTOH, laser sail techniques taken from the recently abandoned Breakthrough Starshot project might be better,,,

Almost all of this is wrong, but I don't have the energy to respond to it.

 

[Byeman]

Frankensats can work - the best is the enemy of the good enough (not to mention affordable). A good many successful craft have been made from repurposed or derived hardware. Skylab was a mash-up of a Saturn 3rd stage and a lunar module. The Nancy Grace Roman observatory uses a repurposed spysat mirror.

not true.
A. There was no LM hardware on Skylab
B. Skylab and RST only used parts from other projects, not a complete spacecraft
c. Psyche and Mars Observer refute your claim

 

[Byeman]

A Uranus orbiter and probe has been identified as a priority and if conventionally-propelled, it will take over a decade to get there, so things like that are more than short term (not likely with current policy of course, but that can change in a later administration). Nuclear-electric could cut years off the flight and make deceleration and orbital insertion much easier, so the technology is attractive in some ways.

This has nothing to do with such missions. Add it really doesn't save much time because of the time to decrease velocity (brake) is just as long as takes to increase velocity.

My guess then is that Jared Isaacman is trying to get a demonstrator for a future crewed interplanetary transport, but as it exists separately from the lunar exploration ecosystem, it may well be sacrificed by this administration or the next.

This does nothing for crew missions.

 

[Brett Davidson]

not true.
A. There was no LM hardware on Skylab
B. Skylab and RST only used parts from other projects, not a complete spacecraft
c. Psyche and Mars Observer refute your claim

A. Apollo Telescope Mount began its development from LM hardware.
B. Obviously. As does SR-1 and Nancy Grace Roman. Your point?
C. Some work, some fail. As with everything. You need to be more specific - what exactly do these missions have to do with my claim, what do they have in common, and which claim? That is not a refutation. Please look up the meaning of the word and explain your points more clearly.

 

[Brett Davidson]

This has nothing to do with such missions. Add it really doesn't save much time because of the time to decrease velocity (brake) is just as long as takes to increase velocity.

Nuclear propulsion (thermal or electric) to and from the moon doesn't add much (if anything) in time. Total mission time can be reduced, even allowing for deceleration because of the advantage of a vastly greater ISP over very long distances. And indeed, the ability to decelerate to enter orbit around Pluto or another KBO is not open at all for a conventionally propelled craft while it is open to a nuclear-electric one.

Have a look at the transit times and allowable masses modelled for outer planet missions, such as Tianwen-4's Uranus component - launch from Earth - proposed - 2029, Uranus flyby (no stopping), 2045.

This does nothing for crew missions.

Please explain further. SR-1 is presented as a probe but seems overdesigned for that role. It closely resembles a later Mars Reference Mission, so I'm speculating that its best role in this form would be to demonstrate key technology and architecture that would latter be applied to crewed missions, reducing technological risk and costs for a late 30's-40s mission.

JIMO was cancelled because of its massive cost but considering Webb's insane overruns, all of that new technology loaded into one big spacecraft would doubtless have also come in at multiples of its already unfeasibly high cost estimates. Since NASA has studied nuclear-electric crewed missions to Mars and they've apparently pulled back from nuclear-thermal as a policy (DRACO was cancelled), then SR-1 would do a good job in developing the technology. That wouldn't be nothing.

 

[Brett Davidson]

Almost all of this is wrong, but I don't have the energy to respond to it.

You can do better than that, in terms of both content and tone.

If you did, I'd be grateful to be informed. After all, I am only speculating.

 

[Scott Kenny]

I'm still waiting for someone to propose a nuclear-ramjet atmospheric probe for the outer planets.

It launches having never taken the reactor critical, so in the event of an oops there's no extra nastiness to deal with. But it could operate for months or years in that atmosphere. Whether Jupiter, Saturn, Neptune, Titan, or any other place with atmosphere.

 

[Brett Davidson]

I'm still waiting for someone to propose a nuclear-ramjet atmospheric probe for the outer planets.

It launches having never taken the reactor critical, so in the event of an oops there's no extra nastiness to deal with. But it could operate for months or years in that atmosphere. Whether Jupiter, Saturn, Neptune, Titan, or any other place with atmosphere.

Good way to find out if there's intelligent life there too - they see that thing trailing radioactive exhaust across their skies and they'll surely introduce themselves to us. Quite assertively.

 

[Scott Kenny]

Good way to find out if there's intelligent life there too - they see that thing trailing radioactive exhaust across their skies and they'll surely introduce themselves to us. Quite assertively.

You'd expect to detect radio signals first. lights of cities at night. etc.

But yes, if there was intelligent life on those planets they'd probably shoot at it. Which means we should fit such a probe with military broadband RHAWS and MAWS, laser warning systems, etc. Actually, I guess ESM/SIGINT gear would be the more accurate desctiption.

Not exactly NASA standard but something that could also give interesting data to the scientists, once you figure out how to convince the military to clear some scientists to see it.

 

[Brett Davidson]

I'm still waiting for someone to propose a nuclear-ramjet atmospheric probe for the outer planets.

It launches having never taken the reactor critical, so in the event of an oops there's no extra nastiness to deal with. But it could operate for months or years in that atmosphere. Whether Jupiter, Saturn, Neptune, Titan, or any other place with atmosphere.

Aha!

https://www.niac.usra.edu/files/studies/final_report/510Maise.pdf