Magnetic wand and lint rollers may be among the tools NASA uses to keep dangerous lunar dust at bay when it returns to the Moon around 2020.

While hailed as a potential source of oxygen and metals, Moon dust is a concern because doctors fear the smallest grains could lodge in astronauts' lungs, possibly causing long-term health effects.

Now, NASA is working on a number of ways to reduce the amount of lunar dust astronauts are exposed to - from simple grates on the floor to streams of liquid usually used to flush contaminants out of photocopiers.

Even during the relatively short Apollo Moon landing missions nearly 40 years ago, astronauts reported difficulty breathing.

"It turns out what we did in Apollo was probably the worst way we could have handled it operationally," says Kriss Kennedy, project leader for architecture, habitability and integration at NASA's Johnson Space Center in Houston, Texas, US. That is because the Apollo landers did not have airlocks, so the astronauts had to live among the dust for days.

Air showers

So the agency plans to set up an airlock on the first lunar trips, which are expected to last just a week. That way, astronauts can take off their spacesuits and boots in a sort of 'mudroom' or entryway without tracking dust into their living quarters.

The airlocks on subsequent missions will become more advanced, with metal gratings outside them to collect lunar soil, or regolith. Inside, they may also be fitted with "air showers", wherein blasts of air from above whisk dust to a grated floor below - just like those used outside of cleanrooms on Earth.

These measures could help remove 90 to 95% of the dust coming into the spacecraft, Kennedy told New Scientist.

The methods may be especially good at removing large particles of dust. But getting rid of smaller particles - which some scientists believe pose more health risks - may require more ingenuity.

Magnetic wand

That is because they harbour strong forces between their molecules, known as van der Waals forces, which make it tricky to free them once they stick to a surface.

So engineers have come up with a variety of solutions that exploit different properties of the powder.

Some lunar dust carries an electrostatic charge thanks to ionising radiation hitting the Moon's surface. So air filters could be built to attract charged dust particles.

Because some of the particles are magnetised, the air filters could also be equipped with magnets, and astronauts could wave a magnetic wand over their suits to attract the dust after a Moonwalk.

NASA might also try to blow the dust away with cans of compressed air - the same kind usually used to clean off computer keyboards on Earth.

Flush out

Another technique borrowed from Earth-bound offices involves carbon dioxide snow cleaning systems, which are used to clean photocopiers and telescopes. These systems flush out contaminants with a stream of liquid CO2.

But getting heavy carbon dioxide tanks to the Moon may be too much of an undertaking given all the other gear that must be transported there, say engineers. Instead, they say the system might be better suited for Mars, where carbon dioxide could be extracted from the atmosphere.

A lighter-weight option takes a page from pet owners the world over. NASA may simply use sticky surfaces - rather like lint rollers - to remove dust.

They may also use coveralls that could go over the spacewalker's pressure suit and be thrown away after a trip outside the lunar habitat. Engineers at Johnson Space Center are also investigating spacesuit materials that are impervious to dust.

Resistant materials

But much of NASA's research is likely to focus on simply designing good seals to keep it outside key modules and spacesuits and coming up with materials that are resistant to the dust's abrasiveness.

"I think that a lot of the solution is kind of boring - good old-fashioned engineering," says Sandra Wagner, head of planetary environment management and integration at Johnson.

Dust may be a niggling problem for NASA in its plans for the Moon, but it's not insurmountable, says Rajiv Kohli of Johnson.

"There are no showstoppers per se," Kohli told New Scientist. "Most of the problems that we think we have are manageable."