Martian dust could be a serious health hazard for future missions to Mars. Credit: NASA/AI. SpaceFactory
To quote NASA associate administrator Jim Reuter, sending crewed missions to Mars by 2040 is an “audacious goal.” The challenges include the distance involved, which can take up to six months to traverse using conventional propulsion methods. Then there’s the hazard posed by radiation, which includes increased exposure to solar particles, flares, and galactic cosmic rays (GCRs). And then there’s the time the crews will spend in microgravity during transits, which can take a serious toll on human health, physiology, and psychology.
But what about the challenges of living and working on Mars for several months at a time? While elevated radiation and lower gravity are a concern, so is Martian regolith. Like lunar regolith, dust on Mars will adhere to astronauts’ spacesuits and inflict wear on their equipment. However, it also contains harmful particles that must be removed to prevent contaminating habitats. In a recent study, a team of aerospace engineers tested a new electrostatic system for removing Martian regolith from spacesuits that could potentially remove harmful dust with up to 98% efficiency.
Let’s not sugarcoat it. Exploring the Moon is not for the faint of heart! It’s an airless body, which means there is no atmosphere, the surface temperatures are extreme, and there’s lots of radiation. The low gravity also means you can never really walk on the surface and have to bounce around in a bulky spacesuit until you fall over. And you can bet your bottom dollar people will make a supercut of the footage someday (see below). Then there’s that awful moondust (aka. lunar regolith), which is electrostatically charged and sticks to EVERYTHING!
Looking to take advantage of this, researchers from the Massachusetts Institute of Technology (MIT) began testing a new concept for a hovering rover that harnesses the Moon’s natural charge to levitate across the surface. On the Moon, this surface charge is strong enough to levitate moon dust more than 1 meter (3.3 ft) above the surface. With support from NASA, this research could lead to a new type of robotic exploration vehicle that will help astronauts explore the Moon in the coming years.
A false-color view of Saturn's moon Hyperion taken during a Cassini flyby in September 2005. Credit: NASA/JPL-Caltech/Space Science Institute
Ever taken a balloon and rubbed it against your hair? That’s an example of electrostatic charging, which you see as the balloon briefly attracts strands of hair against your head. Turns out a similar process is taking place on Saturn’s moon Hyperion. More astounding, it wasn’t until recently that scientists saw a curious effect on the Cassini spacecraft in 2005.
As the machine whizzed by the small moon, Cassini was blanketed in electrons from Hyperion’s electrostatically charged surface. It’s the first time scientists have seen static electricity in effect on any airless body outside of the Moon.
The charge comes partly from massive Saturn’s magnetic field, which hits Hyperion’s spongy surface constantly with electrons and ions. The Sun also plays a role, sending ultraviolet light that also strikes the moon’s surface. Scientists found out this happens while studying old data on the Cassini spacecraft, when they discovered “something unexpected” during a close flyby of Hyperion in September 2005.
NASA’s Cassini spacecraft obtained this unprocessed image of Saturn’s moon Hyperion on Aug. 25, 2011. Image credit: NASA/JPL-Caltech/Space Science Institute
Specifically, the spacecraft — which is still in operation today — was briefly connected through magnetism to Hyperion’s surface, receiving a surge of electrons. Cassini emerged from the encounter unharmed, even though team members estimate that it received the equivalent of a 200-volt shock from the moon. Charging events can hurt spacecraft, making this a valuable thing to know about for future missions.
“Our observations show that this is also an important effect at outer planet moons and that we need to take this into account when studying how these moons interact with their environment,” stated Geraint Jones of Mullard Space Science Laboratory (MSSL), University College London. He is a member of the Cassini Plasma Spectrometer (CAPS) team and one of the study’s supervisors.
CAPS is not in operation any more, since the instrument was turned off due to drawing excess current in 2012. But perhaps some of its past data, and observations from other Cassini instruments, can help unveil evidence of charging on other moons.
The tumbling motion of elongated Eros creates a changing brightness. (via transitofvenus.nl)
Previous research concerning some of Saturn’s moons, and the asteroid Eros, suggests that charged dust can move across the surface and perhaps even be able to sail into space against the force of gravity.
Several other instruments were used to gather data for this analysis, including Cassini’s magnetometer, magnetospheric imaging instrument, and radio and plasma wave science instrument.
You can read more about the research, which was led by Tom Nordheim, an MSSL doctoral candidate, in Geophysical Research Letters.
