How will the future Mars Space Suit Helmet design protect Astronauts from Martian Radiation?

Question

Mars Space Suit Helmet Visor's were mostly made up of polycarbonate [1], the same material used for EMU's visor for performing EVA in earth orbit. Meanwhile, Mars' radiation is 2.5x higher. How are we planning to tackle those issues? What new material might be used?

[1] Lousada, Joao & Kamaletdinova, Guzel & Patel, Divyesh & Ramawickrama, Yasith & Oluwafemi, Funmilola Adebisi & de la Torre, Andrea & Heshani, Uthpala & Onevsky, M. & Skvortsov, Sergey. (2017). Approaches and Solutions for Martian Spacesuit Design.

Answer 1

When talking about by "Mars' radiation" and "those issues" it's important to distinguish ionizing radiation from thermal radiation.

Thermal radiation

From the following questions and their answers we can see that it was very important to shield astronauts from thermal radiation.

• What dangers are astronauts exposed to when facing the sun?
• How does the thin gold film in the glass of spacesuit helmets block thermal IR but transmit visible? What's the property?
• Why did the Apollo lunar suits have two visors?
• Does sunlight warm an astronaut's face during a spacewalk?
• Why is gold used in space technology to protection from heat radiation?

Why? because they are wrapped in a suit and will quickly overheat if they aren't being constantly cooled by their "backpacks"

• How have space suits dissipated the heat removed from astronauts? great answer and diagram
• Will suits worn on Mars lose kilograms of "expendable water" each time they are used?
• How were Apollo spacesuits cooled during simulations/rehearsals on Earth?
• Does sunlight warm an astronaut's face during a spacewalk? again, answer estimates 40 watts of heating through the faceplate alone!

Ionizing radiation

I don't have hard numbers but I will estimate that the faceplate is already at least as thick in areal density (grams per square cm) than the suit which covers most of the body. I don't think it makes sense to make the faceplate thicker in order to increase it's ability to shield ionizing radiation because the rest of the body is less protected than the head.

There is of course some UV from the Sun which can produce a nasty sunburn and cataracts in the eyes, but of course since sunlight drops as $1/r^2$ it will be significantly lower at Mars than at 1 AU. The face shield material(s) will be chosen to be absorbing of harmful UV light.