Hey, Let's Burn Some Metal in Zero Gravity

Scientists just want to see what happens.

Firework spark in high speed with black background
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  • The European Space Agency and McGill University are collaborating on a rocket-powered fuel efficiency study.
  • Powdered metal burns more efficiently than other fires and makes power more efficiently than electric batteries.
  • Zero-gravity research touches all sciences, from engineering to biology and brewing.

    European Space Agency (ESA) researchers are heading a project to study discrete fires in zero gravity. Special craft called sounding rockets, which are comparatively cost-effective to launch, give researchers a chance to study inside zero-gravity environments for a few minutes at a time.

    The launch later this month will hold an experiment about burning metals, which scientists say burn in a form they call “discrete burning” rather than the continuous burning we associate with firewood or charcoal. Metals are combustible in certain conditions, and ESA scientists, working with McGill University scientists, believe they can find applications in automotive engine technology.

    Electric cars are less energy efficient in terms of the amount of energy produced from the materials involved. This fact is typically mitigated by how electric cars aren’t using fossil fuels to begin with, so if they’re “wasteful” in the way they generate propulsion, at least they’re wasting renewable and environmentally friendly energy. Scientists are working to increase this energy density.

    The researchers from McGill, facilitated into zero gravity by ESA systems engineer Antonio Verga, designed an experiment to study how much more energy efficiency comes from burning metal. Solid metal doesn’t really burn, but metal powder is very combustible when mixed with the right amount of air.

    This is where the zero gravity comes in, because particles of metal powder can distribute evenly instead of piling together. The resulting chemical reaction is similar to exploding fuel vapor in an engine or the mix of fibers and closed-off air supply that caused the Triangle Shirtwaist Factory fire. Having a proportionally huge amount of oxygen surrounding flammable particles increases combustibility.

    If metal powder in Earth’s gravity isn’t combustible enough, what will scientists learn from the artificial environment of zero gravity? Their hope is to prove the potential of their research in a perfect environment before bringing it, well, down to Earth. With a goal in mind of creating engine parts or other machines for combustion of aerated metal powders, industry could find new avenues for discovery and invention to capitalize on this energy-dense fuel source.

    Best of all, Verga says, the waste product of these discrete metal fires is just oxygenated, and therefore rusty, metal powder leftovers. This can be recycled into usable new metal powder through a chemical reaction that removes the oxygen that has caused the rust in the first place. “[F]uture cars might give a whole new meaning to driving a rust bucket,” Verga says in the press release.

    Before you imagine your new metal-burning car emerging like a phoenix from the flames of a rusty old ride, keep in mind this is preliminary research to help lay the groundwork for more stages of research that will eventually lead to new consumer technology. Zero-gravity environments give scientists across almost all disciplines a way to confirm computer simulation results or otherwise show that their idea works in “real life.”

    The ESA is a collaborative government organization, but scientists can also hire private sounding rockets, the same way they might reserve time in a wind tunnel or particle collider. The same companies that offer seats on zero-gravity human flights rent their rockets for science and take reservations from university researchers. And in the burgeoning private spaceflight industry, entrepreneurs can use existing sounding rocket infrastructure to get a sense of what their own startup could turn out to be.

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