Fwd: R2-D2 rovers could defend against Moon dust

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: July 4, 2013 10:33:11 AM GMT-06:00
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: R2-D2 rovers could defend against Moon dust

 

 

R2-D2 rovers could defend against Moon dust
BY KEITH COOPER
ASTRONOMY NOW
3 July 2013

Robotic rovers sent to explore the Moon will face a major hazard in the form of electrostatically elevated dust, according to a report being presented today at the National Astronomy Meeting (NAM) by Professor Farideh Honary of the University of Lancaster.

An astronaut's boot print in the lunar dust, or regolith. Image: NASA.
 
Rovers have been exploring Mars since NASA's little Sojourner rover in 1997 and have occasionally struggled in dust - Spirit and Opportunity's solar panels became covered in Martian dust, for example. On the Moon, however, dust is a far greater threat. Apollo astronauts reported dust clinging to everything and its abrasive nature could be harsh on a rover's electronics and machinery. The situation becomes worse, says Honary, at the lunar terminator between day and night, where a potential difference builds up, creating an electric field that can charge dust particles and levitate them.

Honary, working with the ONERA, the French Aerospace Lab, simulated a rover on two patches of the Moon, one in full daylight and the other at the terminator. Dust was then added to the simulation and in both cases dust would rise up above the rover. However, in full daylight the dust would move away from the rover, while at sunset or sunrise the dust moves inward towards the rover before accumulating directly above it. This would potentially lead to a rover gathering large amounts of dust on top of it. Given the slow length of the lunar day - 14 days of daylight followed by 14 days of night, sunset and sunrise can last quite a bit longer than they do on Earth.

Astronaut Gene Cernan pictured inside the lunar module of Apollo 17 following a spacewalk on the Moon. Image: NASA.
 
"Both the Moon and Mars have dust but the difference is their atmosphere," Honary tells Astronomy Now. "The atmosphere on Mars has a mitigation effect since charged dust particles can lose their charge to the neutral molecules that make Mars' atmosphere." In addition, Mars' gravity is greater than the Moon's, which can affect how high the dust levitates.

Although more tests need to be conducted to determine exactly how much dust would gather on a lunar rover and what would be considered a safe amount, one possible solution she says is to build a dome shaped rover so the dust simply falls to the ground rather than gathering on flat surfaces. Consequently, perhaps lunar rovers will end up looking more like R2-D2 than Short Circuit in the future.

 

© 2013 Pole Star Publications Ltd. 

 

 

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Moon Dust Could 'Engulf' Lunar Rovers — Especially During Sunrise and Sunset

by Elizabeth Howell on July 3, 2013

http://www.youtube.com/watch?feature=player_embedded&v=0GbRMn3kKvo

That video above is perhaps the ultimate off-roading adventure: taking a rover out for a spin on the moon. Look past the cool factor for a minute, though, and observe the dust falling down around that astronaut.

The crew aboard Apollo 16 (as well as other Apollo missions) had a lot of problems with regolith. It got into everything. It was so abrasive that it wore away some equipment in days. It smelled funny and probably wasn't all that good to breathe in, either. Many have said that when we return to the moon, dust must be dealt with for long-term survival.

Things could get worse at sunrise and sunset. One new study (not peer-reviewed yet) finds a "serious risk" that rovers "could be engulfed in dust." That's because lunar dust appears to have electrostatic properties that, somehow, is triggered by changes in sunlight. (NASA is already doing some serious investigation into this matter using its orbiting missions.)

An Apollo 17 astronaut digs in the lunar regolith to study the mechanical behavior of moon dust. Credit: NASA

What the researchers did, in conjunction with ONERA (The French Center of Aerospace Research) was conduct simulations for two types of lunar regions — the terminator (the day/night boundary) and an area experiencing full sunlight.

"Dust particles were introduced into the simulation over a period of time, when both the surface and the rover were in electrical equilibrium," the Royal Astronomical Society stated.

"In both the test cases, dust particles travel upwards above the height of the rover, but results suggest that they move in different directions. On the day side, the particles are pushed outwards and on the terminator the dust travels upwards and inwards above the rover, regrouping in the vacuum above it. The terminator simulation began with a region void of dust which was later filled by lunar dust particles."

The bottom line? A lunar rover could accumulate a significant amount of dust on the moon, especially if it's sitting at or near the terminator. This could be addressed by using dome-shaped rovers that would see the dust fall off, added lead author Farideh Honary, a physicist at the University of Lancaster, in a statement.

The work was presented at the RAS National Astronomy Meeting today (July 3). A paper has been submitted to the Journal for Geophysical Research, so more details should be forthcoming if and when it is published.

Credit: Royal Astronomical Society

 

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