For telescopes operating in the vacuum of space, or optical equipment in extreme environments, existing coatings are often insufficient. In the Journal of Vacuum Science & Technology Aresearchers in China turned to atomic layer deposition and developed an ultrablack thin-film coating for aerospace-grade magnesium alloys. The team used alternating layers of aluminum-doped titanium carbide and silicon nitride and together the materials prevent nearly all light from reflecting off the coated surface. The coating absorbs 99.3% of light while being durable enough to survive in harsh conditions.