Soon you can take a portable version of the Earth's magnetic field to outer space

She started big.

A likely contender for human missions to Mars

The Earth's magnetic field helps protect humans on Earth's surface. According to D'Onghia, a possible solution would be to have a spacecraft that would bring along its equivalent magnetic field.

Considering NASA's upcoming Artemis mission to send humans back to the Moon in 2024 and travel to Mars in the next decade, D'Onghia's concept could not be more timely. Along with her friend and collaborator, Paolo Desiati - senior scientist at the Wisconsin IceCube Particle Astrophysics Center - D'Onghia developed Cosmic Radiation Extended Warding (CREW) using a Halbach Array.

A Halback array refers to a specific arrangement of permanent magnets that makes the magnetic field on one side of the array stronger. It cancels the field to near zero on the other side. The magnetic field formed is different from that around a single magnet in which an equal strength magnetic field forms on either side of the magnet.

CREW HaT, a new concept for a Halbach Torus, comprises light, deployable, mechanically supported magnetic coils activated by a new generation of high-temperature superconducting tapes which have recently become available.

D'Onghia's configuration produces an enhanced external magnetic field that diverts cosmic radiation particles, integrated by a suppressed magnetic field in the astronaut’s habitat. Basically, a portable version of Earth’s magnetic field to protect astronauts from deadly radiation exposure.

For her brilliant and futuristic concept, D'Onghia was among the 12 researchers who received the NASA Innovative Advanced Concepts (NIAC) program Phase I grants, valued at $175,000, in 2022.

Decades-old concept, but almost forgotten

Space contains radiation from within our solar system, from the sun, and from outside our solar system, called galactic cosmic rays (GCRs).

Radiation can be either non-ionizing or ionizing. Ionizing radiation consists of particles or photons that have enough energy to remove an electron from its orbit, creating a more positively charged atom. Non-ionizing radiation is less energetic and does not have enough energy to remove electrons from the material it traverses. Ionizing radiation includes alpha particles (a high-speed helium nucleus), beta particles (a high-speed electron or positron), gamma rays, X-rays, and galactic cosmic radiation (GCR). Non-ionizing radiation includes radio frequencies, microwaves, infrared, visible light, and ultraviolet light.

Although non-ionizing radiation can be damaging, it can also be easily shielded against. Ionizing radiation, however, can more easily move through substances and so is harder to avoid.

GCRs are a source of chronic space radiation exposure - the heavy ions in GCRs can penetrate both many types of shielding and human tissue. 

Currently, there are two main types of radiation shielding approaches: passive and active shielding. While passive shielding requires a material physically located between a person and a given source of radiation, active shielding utilizes electromagnetism to create the radiation shield. 

Passive shielding could be simple in daily life - an example would be a patient wearing a lead apron over their vital organs while being exposed to X-rays at a hospital. However, in space, it is more complicated, as variations in particle composition and energy spectra can make it difficult to develop a comprehensive shield. 

The best material choices for passive radiation shielding in space are multi-purpose and have a small atomic mass. Materials like polyethylene are considered one of the most effective tools against space radiation.

"Our concept isn't, of course, for the Artemis mission, which is a relatively short trip to the moon. I think the current solutions in place - such as vests that can protect vital organs - are more related to passive shielding. Our approach is more futuristic, in terms of long-term lunar and Martian missions," says D'Onghia.  

Because passive shielding works best to reduce radiation for low-energy (non-ionizing) particles. Therefore, it is considered an immediate solution, not a long-term one.

"The idea for active shielding has been there for decades, but the difference is that we now have new materials and superconductors that can make this concept more feasible than it was. With appropriate research, I believe this is the most promising solution for the future," she says.

What next?

"Right now, we've been awarded the grant for Phase I. We will work on the optimization of this idea. Our initial study must be made more robust and conclusive to show that the proof of concept can work," says D'Onghia.

The team is currently working on solving the weight of the structure - it needs to be lighter. Once proven feasible, the next step would be to explore ways of testing the same in space. Eventually, we will build a prototype, which will hopefully be a game-changer, she adds. 

"I think NASA is fascinated by the novelty of our project - We have proposed a system that is lighter than previous ones. The magnetosphere in our concept is more interesting than the past concepts as it will utilize new-generation superconductors that are lighter and more powerful. Also, the HaT geometry has never been explored before in this context or studied in combination with modern superconductive tapes," explains D'Onghia.

According to the project abstract, the configuration could divert over 50 percent of the tissue-damaging cosmic rays and higher energy ions. "This is sufficient to reduce the radiation dose absorbed by astronauts that is less than five percent of the lifetime excess risk of cancer mortality levels established by NASA," she says. 

The project also proposes a geometric configuration for the magnetic field that doesn't create one in the vicinity or habitat of the astronaut. The previous generation of magnetic fields employed was confined to the spacecraft and trapped secondary particles generated from the primary cosmic rays impacting the spacecraft, D'Onghia tells us.

"Our concept relaunched the idea of active shielding. Ten years ago when the concept was proposed, the structure intended was too heavy and unfeasible because of a lack of new materials. So, it was impossible to get them to space. This may have discouraged NASA because they eventually proceeded with passive shielding. Yet there is a gap for a concrete solution," she adds.

A lasting solution would be working on both, active and passive shielding, and combining them for lunar and Martian missions.

Study Abstract: 

The 21st century will be when human space exploration gets off the ground. NASA’s priority is to send humans back to the Moon in 2024 with the Artemis mission and travel to Mars in the next decade. In parallel, SpaceX and Blue Origin companies are developing the technology to make human access to space routine.

However, achieving this goal is only possible if we can protect the humans we send to space from the damaging effects of cosmic rays and energetic solar radiation. The health risks to astronauts associated with chronic exposure to radiation in space include carcinogenesis, cardiovascular damage, and degradation of the central nervous system. Since the Earth’s magnetic field is responsible for protecting us on Earth’s surface, a logical solution to the problem would be to have a spacecraft bring along its equivalent magnetic field.

Here we propose CREW HaT, a new concept for a Halbach Torus (HaT), which consists of light, deployable, mechanically supported magnetic coils activated by a new generation of high-temperature superconducting tapes which have recently become available. This configuration produces an enhanced external magnetic field that diverts cosmic radiation particles, complemented by a suppressed magnetic field in the astronaut’s habitat.

The HaT geometry has never been explored before in this context or studied in combination with modern superconductive tapes.  It diverts over 50% of the biology-damaging cosmic rays (protons below 1 GeV) and higher energy high-Z ions. This is sufficient to reduce the radiation dose absorbed by astronauts to a level that is <5% of the lifetime excess risk of cancer mortality levels established by NASA.