Nestled on the foot of a steep, forested hill, 16 kilometers exterior Wellington, New Zealand is a slightly unassuming constructing; one amongst many on a analysis campus that was first established within the Forties. From exterior, there’s little to counsel that that is the birthplace of a exceptional piece of expertise sure for the International Space Station (ISS) within the coming months.
The constructing is dwelling to the Paihau-Robinson Research Institute, a part of Victoria College of Wellington. And the expertise being developed there might in the future scale back the house trade’s reliance on chemical rockets.
“Our focus right here is applied-field magnetoplasmadynamic [AF-MPD] thrusters. It’s a category of electric propulsion that makes use of an utilized magnetic subject to speed up ions to extraordinarily excessive speeds,” says Randy Pollock, the chief engineer for house at Paihau-Robinson, throughout a go to to their labs.
This group isn’t the primary to work on AF-MPD thrusters—the expertise has been tinkered with because the Nineteen Seventies—however Pollock and his workforce have overcome a serious hurdle to their utility in spacecraft. Fairly than use typical copper electromagnets to create the magnetic subject, their magnet is made with high‐temperature superconductors (HTS); a category of supplies which have close-to-zero electrical resistance, permitting them to generate sturdy magnetic fields whereas consuming minimal energy.
How Electrical Propulsion Works
In 2023, Paihau-Robinson put in the primary model of their superconducting electromagnet onto an existing ion thruster at Nagoya College in Japan. The magnet operates on the “excessive temperature” (so far as superconductors are involved) of -198.15 °C (75 kelvin). To achieve that temperature, the researchers used a cryocooler—successfully a miniaturized mechanical fridge—that had beforehand been certified for spaceflight. This did away with the necessity for a steady circulation of pricy liquid helium.
They efficiently fired the thruster over 100 occasions, and generated magnetic fields of 1 tesla with lower than 1 watt of magnet energy. That was a 99 % discount in enter energy in comparison with a copper electromagnet, whereas producing a subject 3 times as sturdy.
Again on the lab in Wellington, the workforce are actually creating their very own thruster, which they take a look at inside a car-sized vacuum chamber. Atop the chamber is a mushy toy kōkako—the mascot for his or her mission, and its namesake. The kōkako is a species of chicken native to New Zealand, immediately recognizable because of a wealthy blue wattle below its beak. “To call these missions, we labored with Professor Rawinia Higgins, who’s the deputy vice-chancellor (Māori) at Victoria,” says Betina Pavri, a senior principal engineer at Paihau-Robinson. “Kōkako comes from the truth that the plasma glows a particular blue-purple shade when the thruster is in operation.”
The HTS magnet, barely seen contained in the vacuum chamber, is comprised of four “double-pancake” coils of superconducting tape. It’s in regards to the dimension of a dinner plate, and the ion propellant line runs via the outlet within the middle of it. The cryocooler is simply out of view, but it surely’s the identical space-qualified mannequin the workforce trialed in Japan. The subsequent stage of the undertaking will contain transferring to a smaller magnet, with roughly the identical dimensions as a bagel, with the aim of constructing the system extra suited to spaceflight.
Hēki Will Check Kōkako’s Tech
Kōkako is one half of the analysis effort—the ground-based growth of a sensible AF-MPD thruster. The opposite half has been on constructing a expertise demonstrator that can quickly be mounted onto the outside of the ISS through a industrial experiment portal known as the NanoRacks External Platform. Pavri describes the demonstrator as “a critically essential precursor to the Kōkako thruster,” which is why it’s named Hēki, the phrase for ‘egg’ within the Māori language.
“As I wish to say, we took a place on the chicken-egg query,” says Pollock.
On 7 November, Hēki was packed up and shipped to Houston, the place it’ll bear closing exams at Voyager Space’s amenities. (Voyager Area can be the corporate behind the NanoRacks platform.)
The Hēki demo resulting from arrive on the ISS later this 12 months carries an outline of the story of how the Kōkako chicken bought its blue wattle.Laurie Winkless
Hēki is, in impact, the whole lot wanted for Kōkako, excluding the ion line. Within the middle of the baseplate is a metal bagel—light-weight exterior shielding for his or her smaller superconducting magnet. When in operation, this magnet will generate a subject of as much as 0.5 T, “related in stage to what you’d see inside an MRI machine however in a really small house,” explains Pavri.
“To our information, that is probably the most highly effective electromagnet that can have ever flown,” Pollock says. “So, it took a whole lot of design work to fulfill the very stringent stray magnetic subject necessities of the ISS.”
Sitting simply above the defend is a flux pump—one other new part constructed at Paihau-Robinson. It acts as an inductive power supply that steadily builds present within the magnet over a number of hours. As a result of it additionally makes use of superconductors, the flux pump doesn’t warmth up, which helps keep the magnet’s temperature. It too is new to the house setting. The soda-can-sized cryocooler and the entire help electronics for the system sit on the underside of the baseplate—a choice motivated by thermal management wants.
Testing the Magnets in Area
When put in on the ISS—which on the time of publication, will most definitely be June—the magnet will probably be operated remotely, biking via numerous subject strengths, and testing shutdown situations. Pavri describes the general aim as “an indication that these new applied sciences—the excessive temperature superconducting magnet and flux pump energy provide—can survive and function reliably within the house setting.”
Zenno, an area startup primarily based in Auckland, New Zealand, says it has been testing a superconducting magnet in orbit since 2023. Zenno has not but printed any knowledge on their experiment.
The Paihau—Robinson workforce additionally has a secondary goal for the mission; “an experiment of alternative,” says Pollock, made attainable by their high-field magnet. “Folks have talked because the sixties about utilizing sturdy magnetic fields for shielding in house. Whereas Hēki shouldn’t be the best setup for measuring it, I used to be eager to include sensors to see what impact our magnet may need on the radiation setting.” He sourced two sensors from the Czech Technical University in Prague, putting in one instantly above the magnet, and the opposite a brief distance away inside the enclosure. “As we ramp the sector up and down, I consider we’ll see an impact.”
The ultimate view of Hēki earlier than it’s packed away is its protecting cowl. The coated sheet of steel features a listing of the workforce members who labored on the undertaking, and people who funded its growth. However it’s the entrance that’s most eye-catching. Adorned with the work of latest Māori artist Reweti Arapere, the imagery tells the story of how the Kōkako chicken bought its blue wattle.
“When the astronauts pull this out, we wish to not go away any doubt about the place this instrument has come from,” says Pollock.
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