The Search for the Next Big Idea in Magnetic Field Mapping

In August of 1905, a strange ship set sail from San Francisco Bay. The wooden brig, called Galilee—also the name of the sea where Jesus, riding in a boat himself, once allegedly soothed a storm—had been retrofitted for a new job: The Carnegie Institution‘s Department of Terrestrial Magnetism wanted to sail it around the Pacific Ocean, to measure and map the planet’s magnetic field. That field matters, in part, for navigation. To get around using a compass, you have to know how far off magnetic north is from the static north on your map. And for that, you need a pretty precise idea of how this field drapes across the planet.

To that end, workers removed all the magnetic parts they could from Galilee, swapping, for instance, the steel rigging out for hemp rope, and constructing a new spot high above the ship’s iron bolts, where the scientific equipment would feel their effects less acutely. Galilee swashbuckled through the seawater until 1908, but its science was always stormy: The material alterations were never quite good enough.

“There was too much metal in the boat,” says Mike Paniccia of the National Geospatial-Intelligence Agency. That agency, the NGA, is today in charge of distributing exactly the sort of magnetic-field information the Galilee sought. And it’s currently running a contest called MagQuest, whose final phase started on March 18, to find cool, novel ways to gather that data. The competition reaches out to universities, labs, and private companies, asking for their most innovative new ways to map magnetism.

Back in the early 20th century, the “innovative new way” was just to build a better ~~mousetrap~~ ship. So, soon, the Carnegie Institution constructed its own vessel from the waterline up—aptly named the Carnegie. It had almost no magnetic meddling. Its metal was limited mostly to copper and bronze, which don’t respond to the twists and turns of magnetism. The Carnegie sailed, sucking up data all the while, for 20 years. (Then it exploded during a refueling session—RIP).

You might wonder why, after making 20 years’ worth of magnet maps, people need more of them. It turns out that you can’t just one-and-done map Earth’s magnetic field, because it’s shifting all the time. One must redraw and redraw and redraw.

That perpetual updating was smoother sailing once airplanes could capture magnetic-field data. Today, the task largely falls (up) to satellites, whose readings feed into the World Magnetic Model, which the NGA releases every five years or so (sometimes sooner if the field is changing a lot). It’s part of a larger program called the World Geodetic System 1984, which also has models for gravity and geographic coordinates. Its mission, as Paniccia puts it, is “defining the Earth.” The majority of the magnetic data currently come from the European Space Agency’s Swarm satellites, with additional bytes from a ground-based system called Intermagnet.

Your ability to move about the world without getting lost actually depends on these measurements. Sure, GPS satellites tell us all where we are at any given moment, no matter how far into the woods we find ourselves. But there’s a hitch: GPS doesn’t know what direction you’re facing or moving. When you change direction, pointing your phone down the street till the arrow matches the block you want to head toward, you’re not just using GPS data; you’re also using your phone’s internal compass. Its matchup with your map depends on Earth’s magnetism. Your compass checks itself against the World Magnetic Model, lest it wreck itself and your car.

The model doesn’t just help you get from the office to Taco Bell: Ships and planes—civilian and military—also rely on it. “One of NGA’s biggest customers is the military,” says Paniccia. “If you’re sailing across the ocean in an aircraft carrier, it’s very important you know where you are and you’re not going into enemy territory.”

That requires information from the magnetic model, and hence uses data from the Swarm mission. Swarm uses satellites of the old-school sort: giant, expensive, full of lots of sensors measuring lots of different things, including but not limited to magnetism. “It was not launched for the purpose of collecting magnetic data,” says Paniccia. It’s currently funded through 2023 (and may get a life extension), but it won’t last forever, and it doesn’t belong to the US. So now is the time to start thinking about what a newer, better, potentially US-based mousetrap looks like.

“We’re looking for what’s the next best way to get the data,” says Paniccia. Is that small, specialized satellites? Tiny sensors on the ground? “That’s where this MagQuest idea comes from,” he continues. “Let’s open it up.” The agency staff want to see who—at a university, in a lab, or at a private company—has got a big idea.

When the agency opened the competition, officials weren’t sure anyone would have any ideas. “Our biggest worry when we started this was we’d get zero submissions. Or two,” says Paniccia. Instead, during the first phase, they got 40 competitors, all of whom sent in descriptions of the systems they’d like to construct.

The 10 winners of that phase each got $20,000—with no stipulations or earmarks, just cold cash. In the second phase, competitors had to drill down on the details of their instruments. They had to produce detailed designs and plans for how they would collect data, including what their sensor would be like, what platform it would be on, and how they would analyze the data. How would the system perform? What were its risks? And how might the team manage a future program? Based on those schemes, five winners split $1 million total.

Now, in the just-announced Phase III, innovators will bring their polar visions even closer to reality, vying for a $900,000 prize. The NGA isn’t under any obligation to buy the winning technology, or any magnetism-measuring technology, after the competition. But it may. “We have planted the seed that at some point in the future NGA is most likely going to put in a formal procurement for something,” says Paniccia. A winner of MagQuest would likely have a leg up in the quest for that hypothetical contract.

One of the teams, based at the University of Colorado Boulder, is planning to construct a small satellite: 10 centimeters wide and high, and 74 centimeters long, like a high-tech hot dog. That length isn’t for looks. The device that will measure the magnetic field—a magnetometer—will go on one end. The rest of the setup goes on the other end. That’s because the gear—like the metal on the long-gone boat—could mess up the magnetic measurements. Keeping the parts away from each other makes the data cleaner.

And keeping the whole apparatus small and uncomplicated—spacing out the instruments but not using a robotic arm to do so, for instance—is meant to appeal to NGA’s goal. Stuff that goes to space doesn’t live forever—radiation degrades it over time, for instance. So sometimes your best bet is to build clones that you can just keep launching. “If we’re going to have a solution that’s going to last for decades, we’re going to have to replace it,” says Boulder’s Bob Marshall, a professor at the Colorado Center for Astrodynamics Research and a leader of this MagQuest team. Small, simple satellites like this are inexpensive(ish). While it’s not trivial to send up reinforcements, it’s not nearly as costly as launching another Swarm.

Five other teams are also reaching for the MagQuest crown. The Royal Meteorological Institute of Belgium is developing a network of 103 magnetic sensors that will live on land and on the seafloor. Stellar Solutions is working on mini-magnetism-measurers that could ride aboard already-planned satellite missions, as well as on the ground. Spire Global, Iota Technology, and SB Technologies are all working on their own small-satellite solutions.

The material in SB Technologies’ magnetometer makes it a little different from the traditional sort: It involves a diamond. “A specially-engineered diamond,” says Rachel Taylor, SB’s cofounder and chief operating officer. The diamond, because of natural impurities, is super-sensitive to magnetism, and its quantum properties change as it encounters different magnetic conditions. The device shoots a green laser into the diamond, which excites it and makes it glow red. The red light changes with the magnetism in a quantifiable way, which allows researchers to measure the magnetic field.

Such shiny, compressed carbon devices should work well in space: Diamonds don’t react that much to the extreme temperatures or radiation, they’re small, and they don’t draw a lot of power. And by the end of MagQuest’s Phase III, perhaps SB Technologies will convince the NGA that those positives make their magnetometer the best design. Or perhaps one of the other teams will win out.

That decision will come in September (pandemic willing). The most important quality in a candidate? “In an ideal, perfect world, whatever it is we land on is something that can get data—good data—for many, many years,” says Paniccia. “Something that’s easily replenished.”

After all, the US has been taking this sort of data since 1905. “I expect we’ll still be collecting it in 2105,” says Paniccia.