Historically, the aerospace industry has relied on thrusters, or a combination of reaction wheels and magnetic rods, to control the attitude, control, and positioning of spacecraft. But these all take up a lot of space and mass, and limit how long the spacecraft can stay in orbit. New Zealand-based Zenno Astronautics has come up with an alternative to these heavy and time-limited propulsion systems. The core technology is an electromagnet that generates a very strong magnetic field, which can interact with other magnetic fields, such as those on other spacecraft, or even the magnetic field of the Earth itself, to generate torque.
The startup’s first propulsion system is called the Z01 or Supertorquer, and as the company’s founders explain it, it’s fairly simple: with a coil of wire (for engineers, it’s also called a solenoid) Create an electromagnet. The electromagnet generates a strong magnetic field, which then interacts with Earth’s magnetic field, enabling the satellite to connect itself to Earth.
Previous attempts to develop this technology have been limited by how much current you can push through a piece of conventional wire. Zenno’s breakthrough is the use of a high-temperature superconducting wire that has zero resistance to the flow of current, so it can push large amounts of current through it. The greater the amount of current, the stronger the magnetic field. The company also addressed other bottlenecks, such as the need for wires to operate at around 80 Kelvin, or minus 193 degrees Celsius, which is much cooler than the vacuum of space.
The result is a system that the company says takes up 20 times less space than conventional propulsion systems. In addition to pointing to satellites, electromagnetic systems can be used for inter-satellite interactions, such as orbital debris removal, spacecraft docking, or in-orbit servicing. Most spacecraft have things that interact with electromagnets, like magnetic moment rods, so the technology is compatible with older spacecraft, even if they don’t have Zenno-equipped systems.
The company is also working to use its technology to shield the interior of spacecraft from the massive amounts of radiation in outer space. Magnetic fields can be used to deflect charged particle radiation, which could extend the life of spacecraft in orbit or protect crews. This is a key question for deep space crewed missions, including to Mars.