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Antimatter in Motion

Antimatter will never lose its allure when we’re talking about interstellar propulsion, even if the breakthroughs needed to harness it are legion. After all, a kilogram of antimatter, annihilating itself in contact with normal matter, yields roughly ten billion times the amount of energy released when a kilogram of TNT explodes. Per kilogram of fuel, we’re talking about 1,000 times more energy than nuclear fission, and 100 times the energy available through nuclear fusion.

Or we could put this into terms more suited for space. A single gram of antimatter, according to Frank Close’s book Antimatter (Oxford, 2010), could through its annihilation produce as much energy as the fuel from the tanks of two dozen Space Shuttles.

The catalog of energy comparisons could go on, each as marvelous as the last, but the reality is that antimatter is not only extremely difficult to produce in any quantity but even more challenging to store. Cram enough positrons or antiprotons into a magnetic bottle and the repulsive forces between them overcome the containing fields, creating a leak that in turn destroys the antimatter. How to store antimatter for propulsion remains a huge problem.

Here’s Close on the issue:

…`like charges repel’, so in order to contain the electric charge in a gram of pure antiprotons or of positrons, you would have to build a force field so powerful that were you to disrupt it, the explosive force as the charged particles flew apart would exceed anything that would have resulted from their annihilation.

As with so many issues regarding deep space, though, we tackle these things one step at a time. Thus recent news out of CERN draws my attention this morning. Bear in mind that between CERN and Fermilab we’re still talking about antimatter production levels that essentially have enough energy to light a single electric bulb for no more than a few minutes. But assuming we find ways to increase our production, perhaps through harvesting of naturally occurring antimatter, we’re learning some things about storage through a project called PUMA.

The acronym stands for ‘antiProton Unstable Matter Annihilation.’ The goal: To trap a record one billion antiprotons at CERN’s Extra Low ENergy Antiproton (ELENA) facility, a deceleration ring that works with CERN’s Antiproton Decelerator to slow antiprotons, reducing their energy by a factor of 50, from 5.3 MeV to just 0.1 MeV. ELENA should allow the number of antiprotons trapped to be increased by a factor of 10 to 100, a major increase in efficiency.

Image: The ELENA ring prior to the start of first beam in 2016. Credit: CERN.

The PUMA project aims to keep the antiprotons in storage for several weeks, allowing them to be loaded into a van and moved to a nearby ion-beam facility called ISOLDE (Isotope mass Separator On-Line), where they will be collided with radioactive ions as a way of examining exotic nuclear phenomena. The nature of the investigations is interesting — CERN has two experiments underway to study the effects of gravity on antimatter, for example — but it’s the issue of storage that draws my attention. How will CERN manage the feat?

This update from CERN lays out the essentials:

To trap the antiprotons for long enough for them to be transported and used at ISOLDE, PUMA plans to use a 70-cm-long “double-zone” trap inside a one-tonne superconducting solenoid magnet and keep it under an extremely high vacuum (10-17 mbar) and at cryogenic temperature (4 K). The so-called storage zone of the trap will confine the antiprotons, while the second zone will host collisions between the antiprotons and radioactive nuclei that are produced at ISOLDE but decay too rapidly to be transported and studied elsewhere.

Thus ELENA produces the antiprotons, while ISOLDE supplies the short-lived nuclei that CERN scientists intend to study, looking for new quantum phenomena that may emerge in the interactions between antiprotons and the nuclei. I’m taken with how Alexandre Obertelli (Darmstadt Technical University), who leads this work, describes it. “This project,” says the physicist, “might lead to the democratisation of the use of antimatter.” A striking concept, drawing on the fact that antimatter will be transported between two facilities.

Antiprotons traveling aboard a van to a separate site are welcome news. In today’s world, low-energy antiprotons are only being produced at CERN, but we’re improving our storage in ways that may make antimatter experimentation in other venues more practical. Bear in mind, too, that an experiment called BASE (Baryon Antibaryon Symmetry Experiment), also at CERN, has already proven that antiprotons can be kept in a storage reservoir for over a year.

Image: A potential future use for trapped antimatter. Here, a cloud of anti-hydrogen drifts towards a uranium-infused sail. Credit: Hbar Technologies, LLC/Elizabeth Lagana.

We’re a long way from propulsion, here, but I always point to the work of Gerald Jackson and Steve Howe (Hbar Technologies), who attack the problem from the other end. With antimatter scarce, how can we find ways to use it as a spark plug rather than a fuel, an idea the duo have explored in work for NASA’s Institute for Advanced Concepts. Here, milligrams of antimatter are released from a spacecraft onto a uranium-enriched five-meter sail. For all its challenges, antimatter’s promise is such that innovative concepts like these will continue to evolve. Have a look at Antimatter and the Sail for one of a number of my discussions of this concept.


{ 32 comments… add one }
  • Ezsu Ra March 12, 2018, 11:54

    A reverse in anti matter polarity would make matter move in the opposite direction.

    • Ron S. March 12, 2018, 20:06

      I don’t know what this means. You’ll need to explain your assertion.

  • Curt Wohleber March 12, 2018, 12:35

    “Cram enough positrons or antiprotons into a magnetic bottle and the repulsive forces between them overcome the containing fields, creating a leak that in turn destroys the antimatter.”
    Perhaps a stupid question, but if you can make sufficient amounts of one or the other, can’t you combine them to make antihydrogen?

  • Brett March 12, 2018, 12:43

    One of my favorite ideas on how to store antimatter was that you could make a reusable tank out of anti-iron (which can be suspended and controlled with electromagnetism), and then store the rest of your antimatter fuel inside. It’d probably be absurdly expensive and difficult to make, but interstellar travel is going to be incredibly expensive anyways (and you’ll be making a lot of antimatter if you’re using that for propulsion).

    • Ron S. March 12, 2018, 20:04

      Do you know how iron is made? Anti-matter propulsion would be obsolete if we could make iron or anti-iron.

  • Spaceman March 12, 2018, 13:06

    Production and storage are the biggest obstacles to antimatter technology. Production can be solved once we develop a significant off earth presence. Imagine huge solar power arrays in space constructed by robots that could churn out antimatter by the tons! Storage will improve by using submillimeter microtraps as one example. Is there anything in the laws of physics that suggests that we will not be able to store antimatter efficiently and/or in arbitrarily large quantities…isn’t this mostly an engineering challenge albeit a huge engineering challenge?

  • Robin Datta March 12, 2018, 13:16

    If they have antiprotons and positrons, it would seem anti-hydrogen would be possible, and easier to deal with than a lot of antiprotons. Obviously there must be a problem preventng this.

  • Alex Tolley March 12, 2018, 15:33

    Part of the issue of storage is what is being made and how. If one could create anti-iron atoms in bulk, for example, bars of this could be suspended in a magnetic field in vacuum. Storage would then be a far easier task. Manufacturing or finding anti-iron is another issue.

    Manufacture today is a brute force, highly inefficient, process. If we could manipulate quarks, perhaps anti-matter production would be much simpler and cheaper. Theories beyond the Standard Model will need to be found and perhaps, show the way forward. Ideally, we want production efficiencies that require only a low multiple of the energy of that of the produced anti-matter. A pipe dream today, but perhaps not by the time we need it for propulsion. Even in the solar system, anti-matter propulsion using small amounts to heat or accelerate propellant would be a gamechanger. [ It would be an awful weapon too, and therefore its production considered very carefully and tightly controlled .]

    • hiro March 12, 2018, 18:48

      We’ll definitely have anti H2O way before the capability production of any nano-gram of anti Fe, one would call the later engineering impossible.

      Some crazy people also talked about the fusion of anti-H but it should belong to the realm of SF for now.

      • Alex Tolley March 12, 2018, 22:08

        Any material that can be manipulated with magnetic fields will suffice. Diamagnetic aluminum will do as it can be repelled by magnetic fields through induced currents that create an opposing field. So anti- aluminum should work.

        • hiro March 13, 2018, 18:52

          It’s still even harder than transforming Al -> Au. Anything higher than anti-He hits the wall of hardness.

    • Spaceman March 13, 2018, 14:04


      What about the idea of using massive space-based solar arrays inwards of 1AU to produce antimatter in large quantities? Obviously there are myriad logistical and engineering issues with such a plan, but the Sun is our greatest source of energy and nothing in the laws of physics prevents this plan…

  • Michael Spencer March 12, 2018, 15:36

    As anon-scientist but keely interested citizen, perhaps some of the scientific folks hereabouts could tell me: let’s assume that we’ve accumulated scads of anti-matter, and that we are comfortable storing it, moving it about, and generally feeling quite safe with the stuff.

    What then? How does one extract the potential energy- or, more aptly, perhaps, how does one convert the natural tendency for annihilation into something a bit more controllable and useful?

    Historically we convert potential energy into heat, thence easily made into electricity, for instance. It’s a somewhat prosaic path for something as magical as antimatter, surely?

    • Paul Gilster March 12, 2018, 17:05

      More on this issue tomorrow. Extracting the energy is a matter of channeling the pions produced as part of the matter/antimatter annihilation, using a magnetic nozzle. I’ll get into this in the next post.

    • Antonio March 13, 2018, 5:23

      Here you can see a possible concept, an antimatter photon rocket: http://oi67.tinypic.com/2moatqe.jpg

  • ole burde March 12, 2018, 18:09

    If one gram of antimater is too hard to store in ONE place , then perhaps what we need is to store one miligram in a million ,or a billion DIFFERENT places , separated by whatever distance is necesary …and perhaps flying in formation until needed …..would the forces involved decrease with the square of distance ?

  • David Herne March 12, 2018, 19:23

    Guess I’ll do my homework for tomorrow – Hbar Technologies, LLC: NIAC Phase I Progress Report Antimatter Driven Sail for Deep Space Missions

    Also, whenever this subject is broached, I remember fondly – New Scientist, 24 June 1989: With Antimatter to the Stars by Joel Davis. This article looked at the use of pions and also a thermal core as proposed by Bruno Augenstein (then at the Rand Corporation) as two ideas amongst others.


    A very popular topic whenever a breakthrough in some aspect of discovery, storage or use for propulsion is made.

  • HSchirmer March 12, 2018, 19:32

    Well, if you’re thinking about solid antimatter, wouldn’t ionic solids be preferable? Something like anti-lithium flouride, where the constituent atoms are ionized and charged, but have mostly unreactive complete electron shells.

    • Alex Tolley March 12, 2018, 21:55

      How does this help with storage?

  • Charley March 13, 2018, 1:34

    “… the reality is that antimatter is not only extremely difficult to produce in any quantity but even more challenging to store. Cram enough positrons or antiprotons into a magnetic bottle and the repulsive forces between them overcome the containing fields, creating a leak that in turn destroys the antimatter. How to store antimatter for propulsion remains a huge problem. ”

    Oh really, now … You think we all have a problem here ?
    I’m not so sure, if this is a particularly hard aspect in the total scope of problems in handling antimatter (if I may modestly say so myself), in fact I believe that this may be one of the simpler problems regarding handling this rather tricky substance. How can I be so arrogantly sure ?
    Well just so happens that research that has been done at CER N has shown that it is possible with the proper procedure to actually create small quantities of anti-hydrogen molecules. You can look the details of for yourself, but the point here is that antimatter that is in the form of neutral hydrogen molecules possesses none of the magnetic or electrical difficulties that individual free ions possess.

    To whit, one makes up a quantity of neutral anti-hydrogen molecules (a few grams perhaps?) and after you have created the anti-hydrogen molecules you bring the entire mass of material down to something close to absolute zero, in which instance it condenses into a solid form of anti-hydrogen snow (if you will).
    Now before you actually cool it down into a solid mass use. Sprinkle a few positrons onto the anti-hydrogen ultracold gas and the positrons (positive electrons) attach themselves to the anti-hydrogen as it collects together in a vacuum, and the charge imparted to the anti-hydrogen mass now possesses enough of an electrical charge that it can be relatively easy to manipulate using magnetic and electrical fields. And Voilà ! You now have a substance that doesn’t possess an ENORMOUS internal repulsive like charges, and your material can now be relatively maneuvered and used as you see fit by manipulative fields to use when and where you wish to direct the material to.

    I would think from an engineering standpoint that it would be extremely wise to produce small, magnetically confined capsules with the finished solid anti-hydrogen in them such that if there was some kind of potential breakdown of the electrical/magnetic field containing the explosive fuel it would be possible to perform a quick jettisoned of the fuel capsule into outer space where it could detonate at its leisure. But that’s just me. Looking at it from an engineering standpoint; what is everybody think about these ideas ?

  • Werner March 13, 2018, 4:32

    Knowing that matter had gained ascendancy at the very beginning and also knowing that the weak interaction seems not fully explain this fact, the question which rises in my mind: How this and … could this be used to produce antimatter on demand without any accelerator to produce matter/antimatter pairs but flipping electron/proton into positron/antiproton?

  • Michael March 13, 2018, 4:55

    There is a more powerful fuel than even anti-matter and somewhat safer. If we could trap relativistic particles in a magnetic mirror bottle we could have much higher energies per particle as they bounce back and forth. It would need a flat disc like profile and a very, very powerful magnet system, these disc could be stored on top of each to save space. An advantage is that many types of atoms could be used not just hydrogen making a much more compact storage system. There would be radiative losses through syc radiation processes though.


    • Alex Tolley March 13, 2018, 17:27

      So basically the LHC in a convenient vehicle size? ;)

  • Brett Bellmore March 14, 2018, 6:12

    The thing you have to keep in mind is that the whole advantage of antimatter is that it’s an extremely concentrated energy store. If your “bottle” weighs 100 times as much as the anti-matter it holds, you might as well just go with fusion. A thousand times? Go with fission.

    Only relatively light weight storage of anti-matter allows you to take advantage of it.

    This is why proposals to store antimatter in Penning traps or the like are pointless. Unless you can achieve condensed antimatter, and store it in bulk with hardware that really weighs no more than the anti-matter itself, you’re likely wasting your time, given how hard it is to get the thrust out of it, too.

    I don’t think there’s any reason we can’t do that, manufacture anti-hydrogen, cool it to micro-Kelvin temperatures, and suspend it electrostatically. Not just “snowflakes”, big chunks of it.

    Going way out there, if we had a good way of manufacturing higher elements, imagine two space craft, one automated and made of anti-matter, the other manned and normal matter. They’d fly in formation, trading fuel between each other. That would certainly solve the storage problems!

    • Charley March 14, 2018, 12:53

      look at my comment above.

  • Mark March 17, 2018, 10:13

    The solution to the storage of antimatter is so trivial that I’m surprised you guys haven’t thought of it yet.

    80% of the universe is composed of Dark Matter, which as we know doesn’t interact with regular matter except gravitationally.

    Simply construct a tank of Dark Matter and pour the antimatter in. Pour it back out when ready to blast off.

    • Ron S. March 17, 2018, 19:36

      “Doesn’t interact” means that the dark matter container can’t contain anti-matter or matter. The container itself may be impossible unless there exists a chemistry of (hypothetical) dark matter particles.

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