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Mars

Could We Reach Mars Faster With Nuclear Fusion-Powered Rockets? (cnn.com) 67

Nuclear fusion — which releases four times the energy of fission — could theoretically happen sooner in space than on earth, reports CNN.

"And it could help spacecraft achieve speeds of up to 500,000 miles (805,000 kilometers) per hour — more than the fastest object ever built..." With funding from the UK Space Agency, British startup Pulsar Fusion has unveiled Sunbird, a space rocket concept designed to meet spacecraft in orbit, attach to them, and carry them to their destination at breakneck speed using nuclear fusion... For now, Sunbird is in the very early stages of construction and it has exceptional engineering challenges to overcome, but Pulsar says it hopes to achieve fusion in orbit for the first time in 2027. [Pulsar's founder/CEO says the first functional Sunbird would be ready four to five years later.]

If the rocket ever becomes operational, it could one day cut the journey time of a potential mission to Mars in half.

CNN says the proposed Sunbird process would use helium-3 — which may be abundant on the Moon — to generate protons which "can be used as a 'nuclear exhaust' to provide propulsion". (And without generating any dangerous radioactive material.) "It's very unnatural to do fusion on Earth," says Richard Dinan, founder and CEO of Pulsar. "Fusion doesn't want to work in an atmosphere. Space is a far more logical, sensible place to do fusion, because that's where it wants to happen anyway...."

Sunbirds would operate similarly to city bikes at docking stations, according to Dinan: "We launch them into space, and we would have a charging station where they could sit and then meet your ship," he says. "You turn off your inefficient combustion engines, and use nuclear fusion for the greater part of your journey. Ideally, you'd have a station somewhere near Mars, and you'd have a station on low Earth orbit, and the (Sunbirds) would just go back and forth...." Initially, the Sunbirds will be offered for shuttling satellites in orbit, but their true potential would come into play with interplanetary missions. The company illustrates a few examples of the missions that Sunbird could unlock, such as delivering up to 2,000 kilograms (4,400 pounds) of cargo to Mars in under six months, deploying probes to Jupiter or Saturn in two to four years (NASA's Europa Clipper, launched in 2024 towards one of Jupiter's moons, will arrive after 5.5 years), and an asteroid mining mission that would complete a round trip to a near-Earth asteroid in one to two years instead of three.

Other companies are working on nuclear fusion engines for space propulsion, including Pasadena-based Helicity Space, which received investment from aerospace giant Lockheed Martin in 2024. San Diego-based General Atomics and NASA are working on another type of nuclear reactor — based on fission rather than fusion — which they plan to test in space in 2027.

Could We Reach Mars Faster With Nuclear Fusion-Powered Rockets?

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  • by locater16 ( 2326718 ) on Sunday April 06, 2025 @07:06PM (#65285487)
    -with quantum teleportation. See quantum teleportation exists wherein you can use entangled partices and a classical communication channel and you can teleport a quantum state from one place to another at the speed of light! We've already teleported entangled photons, but in principle there's no size limits on entangled states. Now all we need do is scale up entanglement to humans in spacesuit, send half the entangled states to mars with laser receiving apparatus, ensure 100% teleportation fidelity, and boom speed of light teleportation to Mars! If only these lazy "engineers" would get on fulfilling my brilliant vision now that I've done the hard part we'd solve this whole "landing on Mars" thing!
    • by yog ( 19073 ) *

      What happens to the kinetic energy of the astronaut who is instantly transported to another point in space? Standing on the Earth's surface, we are actually moving at a rather high velocity due to rotation and orbital motion. Just plunk someone down on Mars and they might go flying up, down, or sideways at thousands of km/hour.

      • There's no reason to think momentum would be conserved in such a teleportation.

        More to the point, what reference frame are you using to determine the kinetic energy? Relative to the Earth's surface it could be zero. If you're bending spacetime or whatever there's no reason to think you couldn't align the reference frames relative to the planet's surfaces and manipulate things to get them equal long enough to complete the trip.
        =Smidge=

        • There's no reason to think momentum would be conserved in such a teleportation.

          More to the point, what reference frame are you using to determine the kinetic energy? Relative to the Earth's surface it could be zero. If you're bending spacetime or whatever there's no reason to think you couldn't align the reference frames relative to the planet's surfaces and manipulate things to get them equal long enough to complete the trip. =Smidge=

          Speaking of Kinetic energy, there would be quite a lot of it if we went to say Mars, at 4X the velocity we can now. These "Fusion engines" won't have a lot of thrust, so will need to either have traditional chemical engines to slow them down, or perhaps some pretty serious aerobraking to enter an orbit. I haven't done the calculations, but I suspect the amount of aerobraking isn't safe or practical, perhaps hardly possible.

          At least, unlike the EM drive, this is possible. If the moon has a lot of Helium

          • The classic approach is to accelerate to the halfway point, turn the ship around, and accelerate the other way for the second half.

            Not only is this the fastest and safest velocity profile, the constant acceleration acts as artificial gravity for the ship's occupants.
            =Smidge=

            • by yog ( 19073 ) *

              The gravity is a nice bonus... but acceleration would need to be maintained at 9.81 m/s to achieve one gee.

              To get to 100,000 mph by the midpoint to reach Mars at its closest approach to Earth, per Grok, a = 0.0357 m/s
              This is far less than one gee.

              Unless I'm doing this wrong.

              But luckily, we can have a spinning habitat to simulate gravity. For a six month journey, this would be a necessity; it wouldn't do for the astronauts to reach Mars with atrophied muscles and bones.

              • by tragedy ( 27079 )

                To get to 100,000 mph by the midpoint to reach Mars at its closest approach to Earth, per Grok, a = 0.0357 m/s
                This is far less than one gee.

                Unless I'm doing this wrong.

                Well, it should be m/s^2, so that suggests a potential problem. Also, there's little reason to worry about Mars at closest approach or not. It will be a longer trip at average distance, for example, but not by a whole lot because, when it's further to the midpoint, you accelerate more reaching it, so you increase the average speed of the whole trip. Let's double check on what Grok gave you though.

                First, I am not sure why 100,000 mph is the target. The summary mentioned 500,000 mph. I mean, that's probably p

            • The classic approach is to accelerate to the halfway point, turn the ship around, and accelerate the other way for the second half.

              Not only is this the fastest and safest velocity profile, the constant acceleration acts as artificial gravity for the ship's occupants. =Smidge=

              I tried going to their website to see if they calculated for this. Then I stopped. They appear to be what some of us call 3D animation science. A "immersive" experience where you click and drag to make a CG spaceship do something.

              Complete with greenhouse gas emissions savings.... Wut? All the cargo they claim to transport has to come from somewhere has to get to space somehow. Unless I'm mistake, these are a low but continuous thrust engines. Still gonna need the dirty high thrust Chemical engines to get

              • > Complete with greenhouse gas emissions savings.... Wut?

                One part of that is easy and extremely obvious; You understand that less cargo means less fuel is needed, right? A more efficient engine - able to provide more specific impulse for less fuel - means your launch mass is lower, which means you're using less fuel to launch (and less fuel to launch that fuel), which means lower GHG emissions either directly if that fuel is carbon based or indirectly as the fuel doesn't need to be manufactured (e.g. hyd

          • by tragedy ( 27079 )

            At least, unlike the EM drive, this is possible. If the moon has a lot of Helium 3 to spare.

            It's theoretically possible at least. We still don't know if sustained Helium 3 fusion actually is possible on the scales (power, weight, physical volume, etc.) needed for something like this. There might be material limits that mean that it just can't work. Now, there might be some version of a fusion drive that will work, even if sustained fusion does not, such as a Dyson drive but, at the moment, there are few more guarantees than the EM drive.

            • At least, unlike the EM drive, this is possible. If the moon has a lot of Helium 3 to spare.

              It's theoretically possible at least. We still don't know if sustained Helium 3 fusion actually is possible on the scales (power, weight, physical volume, etc.) needed for something like this. There might be material limits that mean that it just can't work. Now, there might be some version of a fusion drive that will work, even if sustained fusion does not, such as a Dyson drive but, at the moment, there are few more guarantees than the EM drive.

              To me, the big issues with all these pie in the sky "breakthroughs" is their need to have really exotic chemistry, for present day fusion power, they need Tritium. This Rocket needs Helium-3, which may or may not even be available in the amounts needed, as you note. ITER (if it overworks, will just about deplete the world supply of Tritium, and we're designing a rocket we don't even know if we can fuel. It's a fever dream if you ask me.

          • by dryeo ( 100693 )

            Helium 3 on the Moon is going to be mixed in the top of the regolith, thinly spread and hard to mine. More importantly, it is like triple as hard to fuse as deuterium, ie 3 times as much energy (heat) is needed. First is doing any type of self sustaining fusion.
            Might as well build an Orion and use fission if you want to get a lot of mass into Mars orbit.
            56m diameter, 85 m tall, 10,000t ship, with 800 0.35kt bombs could do 5,700t return trip to and from Mars, not sure how long, Saturn is 3 years and 1.300t.

        • by tragedy ( 27079 )

          There's no reason to think momentum would be conserved in such a teleportation.

          Yikes! Wouldn't that mean arriving frozen at absolute zero?

          Of course, this is all very silly, but does provide fodder for some thought experiments about the actual forces involved.

          • > Yikes! Wouldn't that mean arriving frozen at absolute zero?

            No? Not being conserved doesn't necessarily mean annihilation.

            =Smidge=

            • by tragedy ( 27079 )

              Just to note, for pretty much all of this, we have LaPlace's Daemon on retainer and the Heisenberg Uncertainty Principle is weeping quietly in a corner. I mean, the original poster did mention using quantum teleportation and everyone knows that the word quantum is an excuse to throw everything out the window.

              I would actually very much think that the lack of conservation of momentum would mean the annihilation of momentum, or at least the specific momentum that existed before, however there's a good point th

        • There's no reason to think momentum would be conserved in such a teleportation.

          How about the fundamental properties of space-time? Conservation of momentum is a consequence of the translational symmetry of space. Quantum teleportation is not "magic", it's a reality that exists and so it follows the laws of physics. Quantum teleportation does not require "bending space-time", it is simply the transmission of the quantum state of one particle from one particle to another located elsewhere.

          Indeed, short of finding some way to break the translational symmetry of space or somehow doing

          • > How about the fundamental properties of space-time?

            You're already violating those by teleporting. Inertial reference frames are a thing, and since there is no absolute reference frame for the universe as a whole if you're gonna teleport instantly through whatever mechanism then you would also necessarily be dealing with changing reference frames, so why not manipulate them too so your momentum as experienced by you is conserved while your momentum from the perspective of an outside observer is violated

            • You're already violating those by teleporting.

              No you are not. Quantum teleportation is a real thing, albeit so far at the single particle level. It is not "instantaneous", it transmits information at the speed of light or slower. Furthermore since the laws of physics are the same for all inertial reference frames either momentum is conserved for everyone or it is conserved for nobody: you cannot pick and choose.

              Once you make one wild concession about the laws of physic

              Nobody is making any concessions about the laws of physics. Quantum teleportation [wikipedia.org] is estanlished physics and works absolutely fine within our

          • by tragedy ( 27079 )

            Momentum will be conserved.. but there's no universal coordinate system (as far as we know). So the momentum would be conserved relative to a reference point. Also, bear in mind that we're not talking about traditional conservation of momentum or energy. This kind of teleportation involves throwing energy at the problem at the destination to recreate the conditions at the point of origin.

            • Momentum will be conserved.. but there's no universal coordinate system (as far as we know).

              Correct, but relativity tells us that momentum is conserved in all inertial reference frames so we don't care: effectively it means that momentum is conserved in any and all coordinate systems in any inertial reference frame. So pick one and use it, it doesn't matter which you pick momentum will be conserved.

              Also, bear in mind that we're not talking about traditional conservation of momentum or energy.

              Yes we are. There are not "types" of conservation of energy and momentum. Indeed, in relativity the two are combined into conservation of 4-momentum which comes directly from the translational symmetr

      • Just plunk someone down on Mars and they might go flying up, down, or sideways at thousands of km/hour.

        This is admirably dealt with in the Lensman series [wikipedia.org]. The author makes use of an inertialess drive that, among other things allows any ship using it to travel faster than light, with the only limit on its speed being the friction caused by whatever dust or other debris it encounters. However, when the drive is turned off the ship's velocity and momentum returns to that which it had before the drive was
    • I liked the opening to Pandora's Star, by Peter F Hamilton. The first astronauts landing on Mars are met by someone just standing there, visiting through a wormhole.
    • by Tablizer ( 95088 )

      You missed April 1st by 5 days.

    • #mood

      I read this story, and immediately thought: âoeif only we had this invention to use that unobtainium thing which will need these other limitations overcome.â

  • by algaeman ( 600564 ) on Sunday April 06, 2025 @07:19PM (#65285511)

    Sunbirds would operate similarly to city bikes at docking stations

    My city bikes do use fusion (at a distance) power.

  • I was kinda bummed when the manhole cover from operation Plumbbob finally lost the record. I always found it hilarious that the fastest man-made object held the record for decades and was a complete accident.
    • Plumbob still holds the acceleration record and, fundamentally, that actually matters the most. Our space-time defines an absolute scale for acceleration while there is no absolute scale for velocity. Indeed, in 6 months time almost every manmade object will travelling at about 60 km/s relative to it's velocity now simply due to the orbit of the Earth around the sun which is a higher velocity that plumbob.

      However, it's acceleration record still reigns supreme as far as I know and that is something that c
  • WOW
    He3 from the moon. He3 is 50,000USD a gram. And getting it from the moon unicorn ferry pixie dust is not going to make it cheaper.
    Gold is only 95 or so per gram.
    FUSION is just not going to happen we do not have the materials probably anywhere in the entire solar system to make it work.

    • The sun does it and it's in the solar system. For neither of us having to put any effort into making fusion work it does feel like you're awful confident it will never happen
      • Jupiter is a failed star you would need a couple hundred more of them to get it to ignite.
        The Sun works because of Mass to raise the pressure enough and temp for it to work. We can due it and have done it here on earth its called a thermonuclear weapon. How ever we have no way to contain it.
        There is simply no material science that has worked. Not single project has even been self sustaining.
        The US Navy would have solved the problem 50 years ago if it would have been dooable.

      • The sun does it and it's in the solar system. For neither of us having to put any effort into making fusion work it does feel like you're awful confident it will never happen

        These engines can work. But they work on An element "which may be abundant on the Moon".

        Does the moon have enough Helium three to support a fleet of Fusion rockets? I'm kind of doubting it.

        • Fusion works yes. We just can not get more energy out of than we put in to it.
          The best we have done is a couple of order's of magnitude loss. So we put in a million watts and we get 1000wats back.

          • Fusion works yes. We just can not get more energy out of than we put in to it. The best we have done is a couple of order's of magnitude loss. So we put in a million watts and we get 1000wats back.

            I should have written it differently These engines in principle can work.

        • they shout s small nuke out the ass then detonated it. This is not working.

  • If the UK Space Agency had any credible space based experience I 'might' take them more seriously.
    The only thing that would have been funnier is if this was the French saying it.

  • by hwstar ( 35834 ) on Sunday April 06, 2025 @08:04PM (#65285591)

    Helium 3 is extremely scarce. We would need to get it from somewhere other than Earth.

    There may be enough Helium3 on the moon, but it hasn't been confirmed as to how much there is by lunar probes and if it is able to be mined efficiently.

    At least one startup is persuing it:

    https://www.newscientist.com/article/2472195-how-a-start-up-plans-to-mine-the-moon-for-a-rare-form-of-helium/

    • Tritium is an isotope of Hydrogen and probably what they’re planning to use rather than alpha particles at higher temperatures. He3 is an alpha particle and not scarce, tritium is scarce and has a short half life so you can’t just store it. Ask any country with nuclear weapons.
  • Consider past efforts in nuclear fission rockets:
    NERVA: https://en.wikipedia.org/wiki/... [wikipedia.org]
    Project Prometheus: https://en.wikipedia.org/wiki/... [wikipedia.org]
    Project Rover: https://en.wikipedia.org/wiki/... [wikipedia.org]
    Project Timberwind: https://en.wikipedia.org/wiki/... [wikipedia.org]

    There's likely more projects that were worked on by the USA, and in other nations. Out of completeness I'll include Project Orion but that is an insane idea: https://en.wikipedia.org/wiki/... [wikipedia.org]

    There's also KRUSTY/Kilopower combined with an electric rocket engine, but th

    • A common theme I'll see in mentions of planned missions to Mars is that it would last about 2 years due to how the orbits of Mars and Earth align, this often coincides with the idea of a Mars Cycler: https://en.wikipedia.org/wiki/... [wikipedia.org]

      The cycler just seems to make lots of sense. I'm surprised it hasn't been attempted as a method to move probes and other unmanned craft to Mars and back. Or on a smaller scale, a lunar cycler. The propulsion needs for interplanetary travel are different than the needs for takeoff and landing. Separating them into two different craft just seems like a good idea to try.

  • Betteridge (Score:5, Insightful)

    by PPH ( 736903 ) on Sunday April 06, 2025 @08:36PM (#65285637)

    No,

    Theoretically, yes. But given the size of inertial confinement fusion reactors and the need to scale them up even more to do Helium 3 reactions, the spacecraft would be massive. And practically all of that would be engines. It would be like building the Saturn V to go to the moon, transporting the bird poop deposited on it while rolling it from the assembly building to the launch pad. As its primary cargo.

  • We know how to create a fusion powered spacecraft.

    See Sunjammer by Arthur C Clarke

  • by using spice-fueled guild navigators to fold space... ahhh the things you can accomplish with imaginary technology.

    The real problem with this recurring promise of faster travel using nuclear fusion is that, ever since the 1930s it has always been "only 30 years away". The predicted date seems to scoot a little to the left or right depending on the year of the prediction, but it's always about 30 years (long enough for the predictor to be retired before the prediction is falsified). The cause of this is si

  • Only problem is it requires more energy to cause fusion to happen than it releases. Unless of course you are doing it in a thermonuclear device. IE using a fission reaction to cause the fusion reaction to happen. That idea is very old see project orion. Better idea is the nuclear salt water rocket concept for extreme speed or maybe a rocket that uses a nuclear reactor to generate power for an ion propulsion system. Chemical rockets would be used for lift off to orbit and landing. Use Thorium for fuel becaus
  • Surely, that will be enough buzzwords for me to cash out my idea to some willing investors.
  • The crew however did not survive the braking manoeuvre!

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