NASA says some of the particles are small enough to reach deep into the lungs and enter the bloodstream.

The bloodstream is the flow of blood through the body.

Fine particles can reach deep into the lungs and enter the bloodstream.

The bloodstream is the flow of blood through the body.

And what does “ultrafine” mean here?

“Ultrafine” means extremely small.

It also found ultrafine particles around 100 nanometers.

Here, “ultrafine” describes particles that are extremely small.

NASA also says studies have shown that ultrafine particles can travel from the nose to the brain along a nerve involved in smell.

Here, “ultrafine” describes particles that are extremely small.

These particles are much smaller than the dust that earlier measurements on Mars could resolve.

Here, “resolve” means to detect or show clearly with a measuring instrument.

It looked at dust that had settled on different materials.

Here, “settled” means came to rest on a surface.

NASA reports that a Teflon sample readily collected fine dust.

“Readily collected” means gathered the dust easily.

The results could help engineers choose materials and protective coatings for future suits and habitats.

Protective coatings are thin layers put on a surface to help protect it.

These include perchlorates, a type of chemical salt that can disrupt thyroid function, and reactive iron, which can damage cells.

Here, “disrupt” means interfere with the thyroid’s normal work.

Mars dust is less abrasive than lunar dust, but its very small particles still raise concerns about health and keeping dust out of living spaces.

Here, “abrasive” means able to scrape or wear away a surface.

It scratched visors, wore down outer layers of spacesuits, and damaged seals.

“Wore down” means gradually damaged or weakened through rubbing.

NASA’s report also points to suitports, where astronauts enter suits attached to the outside of a habitat, and to airlocks with two chambers.

Suitports are openings where astronauts put on suits that are attached to a habitat’s outside.

NASA’s report also points to suitports, where astronauts enter suits attached to the outside of a habitat, and to airlocks with two chambers.

An airlock is a space with doors that lets people move between areas without letting all the air escape.

And the central point is that this is a measured hazard to plan for, not a report of astronauts becoming ill.

A hazard is something that could cause harm.