Pulsed Plasma Rocket

Howe Industries is investigating a Pulsed Plasma Rocket system that can produce 20,000 lbs of thrust with an Isp of 5,000 seconds. The Pulsed Plasma Rocket (PPR) is smaller, less complex, and more affordable.

They fire a 2 kilogram bullet down a barrel where it gets converted into plasma and generates the thrust.

They think it could enable 2-3 month one-way trips to Mars.

The performance of a propulsion system with high Isp and high thrust allows missions throughout the solar system and beyond which are not possible with current technology. Human missions to Mars in two months are possible. Alternatively, heavier ships containing shielding against Galactic Cosmic Rays are enabled so that the dose to the crew is reduced to negligible levels. This may be preferable for Mars missions or may enable human missions to the Asteroid Belt in acceptable timeframes. A mission to the 550 AU location where the Sun’s gravitational lens focuses can be considered. They are focusing on a large, heavily shielded ship to transport humans and cargo to Mars for the development of a Martian base.

SOURCES- NASA, NIAC, Howe Industries
Written By Brian Wang, Nextbigfuture.com

36 thoughts on “Pulsed Plasma Rocket”

  1. I think it would be tested extensively on supercomputers. Maybe used to justify a new one. Its a very messy engine- the kind of thing you test on the other side of the moon.

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  2. Yeah, I'm well aware that you can radically change the critical mass by changing boundary conditions, or compressing beyond normal density, or tritium boosting, or what have you. I might not be a bomb designer, but I am an engineer who passed all his physics classes.

    All these techniques are still modifying the underlying bare ball critical mass, and so lower that, and you lower the modified critical mass..

    And for a system like this, lowering the minimum scale is pretty important. In part because of that last point you made.

    Though you did note that the percent burnup they're anticipating is quite low? Most of the fissile material is just going to be reaction mass. Very expensive reaction mass.

    That's why I say you'd be better off just going to a full blown Orion drive. Much more efficient use of the expensive fuel.

    I mean, I like the clever modification of a gun type bomb into a rocket engine, but Orion is still more practical.

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  3. What about the benefits? I'm sure living in 1 g has long term negative effects, maybe 0.38 will be easier on the heart, respiratory system, spine, etc?

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  4. True, not a good guy, but who is? As I age I become less endeared with humanity and its incessant lies, manipulative schemes, political chicken-little dramas, "Me too" ideologies that threaten due process, give me – give me you owe me selfishness, and anti racist anti bullying free speech destroying hypocrisy. At least with Zorg – he's honest. He admits he's a monster. The problem with most people is they're monsters too, but their egos won't let them realize it.

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  5. Yeah I think I heard something about that. I was also laughing pretty hard when the Democrats decided that "Me Too" didn't apply to Tara Reade's sex assault accusation against Biden. The verbal somersaults they made in a feeble attempt to show why it was ok not to believe Reade was most hilarious to watch. I'm neither liberal nor conservative and I don't know if Reade was telling the truth. What's most alarming though is the ease with which political partisanship is now threatening due process.

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  6. "The watermelons will hate it."
    I don't believe this is entirely accurate. Greenies don't like nuclear in the earth's biosphere or close proximity. I have never heard them complain about space usage that was built in space and used away from the earth. Space is already full of radiation sources as everyone knows. Because of that fact, even if they opposed it they would find little traction from the public considering the advantages such drives and power sources would give us. Nuclear power and drives coupled with space make as much sense as peanut butter and jelly on sandwiches.

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  7. Nah, tritium boosting a fission bomb, you still get most of the energy from fission. All the fusion does is flood the fissile material with high energy neutrons that are particularly good at sustaining the chain reaction, so you get a higher burnup percentage.

    Basically all our nukes are tritium boosted, for that reason; It just makes the fission a lot more efficient to have some tritium around.

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  8. No, let me amend that: This might end up being tested, because it looks to be useful in certain scenarios, and would keep the bomb lab guys busy so that they don't get bored and take early retirement. But it would be tested in a black program we'd never hear about. NOT by NASA.

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  9. It's nice having workable proposals accumulating in folders, that you can pull out if suddenly you have a need for one. And I like this proposal a lot more than the "assume a fusion reactor" ones, let alone the "assume the laws of physics aren't what we think" EM drive ones, because, hey, it's actually about as speculative as the Manhattan project. I have absolutely no doubt you could make this scheme work, and pretty quickly if it were urgently needed; The bomb labs probably have good enough modeling software to make it work on the first try.

    Mind you, in such a "OMG, we need a high thrust, high ISP drive NOW, or mankind is doomed!" scenario, Orion is still better. It's all around still better, its only downside is "OMG, it uses BOMBS!" Whereas this drive IS a bomb…

    Yeah, it's wasteful spending, busy work for smart specialists you need to keep occupied so they're around when you suddenly need them.

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  10. At least he had the decency to let the priest go after his life was saved. Interesting character, but certainly not remotely a good guy.

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  11. The video refers to HEU, "Highly Enriched Uranium". However, the scale of this thing is highly dependent on the critical mass of the bullet. You want most of the fission happening in the bullet, after all; Any that happens in the barrel is largely waste heat, though you can use it to run a thermal cycle to power the "gun".

    You need an isotope which is both long lived, (Your bullet doesn't melt from decay heat in the fuel store.) and low critical mass. That really limits your options.

    HEU has a critical mass of 52 kg, which is really large. You'd be talking almost an Orion scale system.

    Pu239 would be far superior. It has a critical mass of only 10 kg, and is in good supply, as it's used in nuclear weapons and thermal reactors.

    In an ideal world you'd use Neptunium 236, or Curium 247, both with a critical mass of 7 kg. But they're both insanely expensive.

    Of course, the bullet isn't a full critical mass of material. But it's size is still going to be proportional to the critical mass.

    This is not really a system that can be effectively tested at small scale. And any testing that takes place would have to be treated as a nuclear bomb test, because a nuclear explosion is one of the failure modes, and you're spraying highly radioactive, mostly unreacted plutonium out the end. Clean up after the test would be expensive.

    I don't see this going anywhere until it can be tested in space, by people who aren't nuclear phobic.

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  12. Maybe use a plutonium based compact fission reactor to power a Brayton type cycle for power to the magnets, using liquid metal coolants to transfer heat to liquid Tritium H3, then use excess heat to superheat U238 powder to a gas and expel it through a magnetic rings then use it to ignite the superheated tritium gas within the magnetic rings, then feed it He3 at the end in a semi-magnetic confinement chamber with a controllable confinement at one end to act as the bell. Fission, Fusion, Fusion.

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  13. "They add a bit of tritium boosting and zeta pinch to reduce the critical mass."

    If they do that it becomes a rapid, short burst fusion bomb engine, with a fission spark. Essentially, a violent particle accelerator that doesn't loop and blasts plasma out the end.

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  14. You don't see the inherent brilliance of the idea?

    They can point to functioning fission systems to make it seem like their idea is more realistic than all the "assume a fusion reactor" projects out there.
    But because it needs fissile materials, they have the perfect excuse to avoid doing any actual experimental work. Thus they can never be disproved.
    Meanwhile they keep raising funds (and paying themselves a salary).

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  15. The bullet is made of plutonium or uranium or something? I assumed it would have to be, but that's not mentioned anywhere I could see.

    Otherwise it's one of these ham and eggs articles. But actual fission works.

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  16. Good news, the revolutionaries are turning on themselves in ever greater numbers.

    Last I heard, J.K. Rowling, she who turned a sweet series of children's books about magic into some sort of social justice campaign, has now been declared a fascist for some stupid reason.

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  17. Ah yes, 21st century America. Where the Poppycock's of the world lurk in every dark corner just waiting to twist any innocent fruit into hate speech. They remind me of the Inquisition, gleefully burning free speech heretics at the stake in the name of anti-racism, anti-bullying, whatever. Of course, in the liberal mind anything they disagree with is racist/bullying and therefore hate speech. I just hope I live to see the day where the revolution eats its own.

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  18. Thx. I'm thinking the long term effects, given the significant difference btwn 1g and .38 would lean toward the severe. Perhaps not as severe as zero g, or perhaps at the same level but taking longer to fully manifest themselves. Ultimately, perhaps too severe for a permanent colony unless genetic engineering could compensate. Hopefully, I'm wrong.

    By the way – Zorg is the man! When I first saw that movie back in '98 I rooted for Korben Dallas. Now, Zorg has grown on me. Too bad he got wacked by that bomb.

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  19. We don't know. The only data we have is for 1 g and 0 g. We know 0 g is bad, so we can assume the effects to be something in between 1 and 0 g. It can be very mild long term effects for adults like weakening your muscles and some bone loss, or probably only some effects for gestating mothers and infants.

    Partial gravity is impossible to get for long periods of time here on Earth.

    We could get it on a rotating space station, but that's another thing we don't have.

    That's one of the main reasons to go, actually.

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  20. Question – does anyone know what the theory is for how long someone can survive in Mars' low grav? We all like to discuss the different propulsion technologies that will one day get us there, but what happens then? Zero g has been shown to have serious effects on human health. What's Mars' .38g going to do to us?

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  21. Seriously, you can't tell from the context? "Watermelons" is a slang term in the US for a certain type of environmentalist: "Green on the outside, Red on the inside."

    Never heard it used as a racist term.

    By the way, you sound like somebody filling out a data entry form. Don't bother, I'm already on enough lists that it would be redundant.

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  22. Right. Like I said, you need the people actually living there to be calling the shots. Either able to tell authorities on Earth to go stuff it, or able to conceal what they're doing from authorities on Earth until it's too far along to stop.

    Mars is an ideal planet for nuclear power, given both untouched mineral resources, and the fact that the water there is already substantially enriched in deuterium thanks to selective loss. I expect that they'll be building native CANDU reactors pretty early in the colonization process.

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  23. Greenies will indeed look silly on a dead world without a biosphere except the one we make.

    But then, they'll have the rock huggers, trying to forbid that even a pebble is turned over and changed from the dead state is has been for aeons.

    And don't forget the fuzz they will make if even a single bacterium is found in the rock of Mars (a very likely possibility, even if brought by our landers).

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  24. I console myself that Mars has both abundant, untouched pitchblende deposits, and soon will have abundant airlocks for throwing watermelons out of.

    Nuclear in space will really take off once the people calling the shots live there.

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  25. The watermelons will hate it. 

    My main concern too. Apparently only China and Russia are allowed to send nuclear powered hardware into space. Or rather, they make any complainers shut up.

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  26. OK, moderately clever. It's basically a gun style fission bomb, where the fixed portion is lengthened, and the moving portion enters at high speed. The combination of "bullet" and "barrel" exceeds criticality. 

    Fission in the barrel is distributed over the length, avoiding melting it, while the bullet has nowhere to dump its heat. But you time things so that the "bullet" doesn't actually explode far enough to touch the barrel until it comes out the other end. 

    They add a bit of tritium boosting and zeta pinch to reduce the critical mass.

    This is the sort of nuclear tech that you might have seen in a Heinlein novel, except for those last couple of points.

    I like it. The watermelons will hate it. 

    Oh, and if you don't fire the bullet through fast enough, it blows up in your face. That's a bit of a downside.

    I'd suggest firing two "bullets" down the barrel, one a hollow cylinder, the other a rod to fill the hole. Fire them down it at different speeds, timed so that they reach each other inside the magnetic exhaust nozzle. That would probably really increase burn up and ISP.

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  27. Good.

    We really need to move forward deep space propulsion research.

    SpaceX Starship will be fine and dandy, but some serious thought must be given to reducing travel times in long crewed interplanetary missions.

    For Mars trips, this won't be very different from what Starship is planning (Starship's ~115 days for a one way trip vs 3 months for this), but for longer trips, the bigger Isp could be a real difference in terms of mission duration, mass and life support requirements.

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