University of Tokyo tests a 'magnetic shield' for spacecraft

Researchers at the University of Tokyo have tested an innovative technology aimed at drastically reducing thermal loads on reusable spacecraft during atmospheric reentry. According to Ixbt.com, scientists have moved away from heavy thermal insulation and created a special experimental setup to study magnetohydrodynamic braking. In laboratory tests, a powerful electromagnetic device successfully altered the structure of the heated layer around the model. This is reported by Ixbt.com reports.

It is known that when a spacecraft enters the atmosphere at hypersonic speeds, a shock wave forms in front of it. The surrounding gas heats up to several thousand degrees, partially turning into plasma. Currently, special heat-resistant tiles or ablative materials are used to protect against these extreme temperatures. However, such protective measures significantly increase the structural mass and require constant maintenance.

Advantages of the magnetohydrodynamic approach

The proposed new approach is based on directly influencing the ionized gas. A strong magnetic field should expand the hot plasma layer and push it away from the spacecraft's surface. Theoretically, this not only reduces the heating of the hull but also increases aerodynamic drag, helping to decelerate faster. Previously, such experiments were mainly conducted using permanent magnets installed inside small models.

However, previous methods limited the ability to change the strength and configuration of the magnetic field. Japanese scientists instead used a compact pulsed electromagnet with a system of adjustable coils. During the tests, the model was subjected to a shock wave at speeds exceeding 7 kilometers per second.

Experimental results and prospects

Since the shock wave lasted only tens of microseconds, researchers had to synchronize its occurrence, the electromagnetic pulse, and high-speed camera footage with extreme precision. The experiment achieved magnetic field strengths of 1.24 and 1.58 Tesla. This result is twice as high as the capability of neodymium permanent magnets used in previous setups.

After the electromagnet was activated, the light-emitting layer of heated gas was observed to thicken by 15 percent. This indicates that the magnetic field indeed altered the state and structure of the plasma layer. While this is currently only a laboratory experiment rather than a ready-made space shield, the technology is expected to be tested in real-world conditions in the future.