The Yutu rover on the Moon — a dirty job?
News reports are giving conflicting information about the state of the Chang’E 3 rover Yutu. Some claim that the rover is dead while others indicate that it is responding to radio signals, although it is uncertain whether it will obtain full functionality. Despite this uncertainty, I’m reading reports attributing the demise of Yutu to the baneful effects of lunar dust. The idea being advanced is that the angular and abrasive dust of the lunar surface has probably jammed the moving parts of the rover and possibly coated parts of the structure, resulting in increasing heating of the rover during the lunar day.
There is no reason to believe that Yutu’s problems are related to dust. Lunar dust was a known factor before the flight of Chang’E 3 and given how well things have progressed to date, I cannot believe that its builders were ignorant of the possible negative effects of dust. Fears of these effects are greatly exaggerated. Dust was a problem during the Apollo program because we did not fully understand all of its properties when the equipment used during those missions was being designed. We have since accumulated an enormous amount of information on dust and have developed a variety of different strategies to cope with and mitigate problems. It is much more likely that software or some mechanical-electrical component has failed on the rover. This is harder to diagnose and fix (if possible), but don’t believe all the horror stories you are seeing about the “deadly dust of the Moon.”
It is important to understand the properties of lunar soil, along with its challenges and advantages in order to properly report on our current understanding of the lunar surface. Two U.S. lunar orbital missions, LRO and LADEE (selected to fly during the last administration) are currently orbiting the Moon and collecting more data.
Linked below is information about our current understanding of the properties, problems and promise of the Moon’s regolith.
“Another idea is to keep the suits outside, leaving the interior of the habitat completely dust free. But no matter how carefully we avoid it, some dust will get into places we want to keep clean. Brushing only seems to grind it into porous surfaces. But amazingly enough, we have found that much of the dust is magnetic. Vapor-deposited metallic iron coats the surfaces of many mineral and glass dust grains. This so-called “nanophase iron” (from its extremely small size) makes the dust easily attracted to a simple magnet. A brush made with magnetic bristles will clean surfaces of most of the dust. Incidentally, this same property permits the lunar soil to be fused into glass using low-energy microwaves, allowing us to “pave” roads and landing pads near and around the lunar outpost and to make bricks for construction and radiation shielding…”
Regolith: The Other Lunar Resource
“…The ground up regolith is a readily available building material for construction on the lunar surface. It is an aggregate in the same sense as on Earth, but with some significant differences. We could make lime and water from the surface materials of the Moon but it is very time and energy intensive. Thus, we must adapt and modify terrestrial practice to take advantage of the unique nature of lunar materials. The fractal grain size in the regolith means that we can obtain any specific size fraction we want through mechanical sorting (raking and sieving). Instead of water-set lime-based cement, we can use glass to cement particulate material together. Regolith can be sintered into bricks and blocks, as well as roads and landing pads, using thermal energy (passive solar, concentrated by focusing mirrors) or microwaves that can melt grain edges into a hard, durable ceramic…”
LADEE: Measuring Almost Nothing and Looking for the Almost Invisible
The LADEE mission seeks the faintest of lunar phenomena
“…The day and night hemispheres have different fluxes of electrons from the solar wind and thus, the presence of the terminator can induce an electrical charge in surface materials. It is postulated that this charge might levitate smaller dust particles such that they would hover above the surface. LADEE will attempt to detect and map this dust, both by searching for scattered sunlight with its ultraviolet spectrometer and via the direct detection of dust particles in flight with an instrument on the top of the orbiting spacecraft…”
“-make bricks for construction and radiation shielding…”
That is what is needed for starters. With an HLV, lander, radiation sanctuary, water, and electricity- we can go and set up shop.
Thanks for the links to your earlier articles on this subject. They’re always very interesting and very informative!
The microwave sintering of paved habitat and landing areas would appear to be the easiest solution for mitigating dust around a lunar habitat. And some overalls might help to reduce the accumulation of dust on a pressure suit.
But not even Chester can save James Arness from those deadly electrodes:-)
Marcel
Before it was cancelled Constellation Systems had work going on to mitigate such problems (I was one of the engineers working on the subject). Dr. Spudis lists the generic areas being addressed very well.
I am now going to break my rule about not going off topic, but it is all Marcels fault for bring up the 1951 version of “The Thing form Another World”. Sorry but in addition to my other shortcomings I am an “old movie buff”
A great movie mixing a serious horror plot with iconic director Howard Hawks blend of humor, action adventure and fast paced dialog. Just watched it again in December. A great movie.
OK now everybody, back on topic. 🙂
Actually, Marcel is innocent — he brought up “The Thing” because I used a picture from it to accompany my article on lunar dust all those many moons ago:
http://www.airspacemag.com/daily-planet/the-deadly-dust-of-the-moon-152807519/
I stand corrected. Apologies to Marcel.
No apologies are necessary! I’m glad Dr. Spudis posted that classic scene from ‘The Thing’.
Science Fiction has a long history of inspiring young people into becoming scientist and engineers later on in their lives. Robert H. Goddard, Carl Sagan, and Wernher von Braun were all inspired in their youth by science fiction.
Marcel
Hi Marcel,
Was really just having a little fun with the reference to “The Thing from Another World” (as I said one of my favorite old movies).
But you make a serious point that is worth reinforcing. I went to work on the program, right out of college, in 1982.
At that there were still a number of people that were there that began their careers in the 1950’s in military programs and then transitioned to NASA to work on the Apollo Program. A number of them would tell you that what inspired them to become engineers and eventually work on actually landing people on the Moon was seeing the 1950 movie “Destination Moon”.
One of my favorite movies of all time; still plays well. That everyone keeps giving the pilot-hero a hard time about his crush on the scientist’s assistant is….really the best part of the movie. When they throw kerosene on the creature and light him on fire is still one of the great action sequences in cinema. The remake and prequel do not even come close to matching it.
Dr. Spudis could probably tell the Coast to Coast AM listeners the movie was based on a true story that took place on the Moon when Nazi rocket scientists escaped there from a secret Antarctic base and were attacked by a Lunite. Some of them would believe it.
One of the funniest aspects of The Thing is the attitude of Dr. Carrington, who is perfectly willing and happy to not only throw away his own life, but the lives of everybody at the base as well, all to protect a blood-sucking vegetable from space. A truer portrayal of the mentality of the academic scientist has seldom been realized on screen.
“-the mentality of the academic scientist-”
Craig Venter comes to mind. That guy truly terrifies me. One very good reason to have a Moon base. The genie gets out of the bottle and it could all end here quick.
Hard rock miners who drill and blast for gold in quartz veins with granite formations also have to deal with angular, unweathered dust, and yet they seem to manage…
Would it be practical to manufacture conventional explosives from Lunar Resources for blasting out tunnels to live in?
If all lunar dust is coated with nano phase iron making it very responsive to magnets, how can metals be separated from the regolith?
One would first separate the magnetic components of the soil and then melt the product. As metal is much denser than silicate glass, gravity would separate the two components.
Could one spin the magnet to separate silicates with a small amount of nanophase iron from metallic meteorite bits which are completely metal? Doing so could help reduce the amount of material you would have to melt before separating metal from dross.
Do you think opening and closing solar panels was generally good idea in terms of dealing with the lunar night?
Basically what are they doing? Are trying to keep solar panel warm during night or other parts of vehicle?
It seems with solar panel you may want them not to get very hot during day or accept they become less efficient due to them heating up. And may instead be concerned about how cool they get at night- though not sure cold solar panels are an issue.
If the issue is, as reported, that solar panels keep rest of spacecraft warm, would they make a big difference. Or how much warmer would folded panels keep the spacecraft.
I understand less surface area as general rule has large effect- so folding solar panel reduces total surface area of rover. But if solar panel by itself can survive a lunar night then this is not much of issue. Instead the issue is how well does panels kept rest of vehicle warm and is this a good way to keep them warm. Isn’t there better ways of doing this?
The Soviet Lunakhod rovers of the 1970’s used the same thermal management control as does Yutu — a tiny radioactive “heater” unit to generate warmth and then closing the deployed solar panels at night, which transfers heat to the structure via conduction and also keeps out the dreaded levitated dust. The Lunakhods 1 and 2 survived and operated successfully over the course of multiple lunar nights (11 months and 4 months, respectively).
http://www.businessinsider.com/work-on-seattles-underground-highway-stalls-2014-2
Not easy boring tunnels. I have a whole new respect for geology after this. Does not bode well for building cities underground. If the regolith goes down a certain depth and then hits rock then maybe a technique built upon that characteristic can to be worked out.
One thing is for sure- the radiation is not going away and a way to build sanctuaries may the critical problem in any Moon base plans. As commented on before I like just putting water overhead in an impact crater but that may not work or be efficient at all.
Has there been any real work (as in money spent and research/experiments performed) done on this subject of what we can build on the Moon I wonder?
Thanks for the post, interesting article, however it is not easy doing lots of things that are still worthwhile doing.
The failure of a newly designed seal is not necessarily a “show stopper” and an article that says simply says “some are wondering”, then quotes only one source (“Ben Schiendelman”) as saying there are better ways to spend the money is not definitive.
A skeptical observer would wonder if “Ben Schiendelman” was an opponent of the project before this setback occurred.
I do not know whether or not this concept is flawed (neither I suspect can you). But I do know that those who try to accomplish things always have a much more difficult task than those that simply want things to not be accomplished. The latter only have to wait for a setback (no matter how major or minor) then call for the project to be shut down.
I would suggest waiting for (a lot) more information before giving up on the tunnel and certainly before assuming such tunneling techniques cannot be used on the moon.
Just managed to get through to the source website for the “Ben Schiendelman” reference.
It describes him as follows:
Ben Schiendelman joined in 2007 to better consolidate news and information about our upcoming transit expansions, and to build a better base to further grow our system. He previously wrote the blog Higher Frequency, and worked on the 2008 Mass Transit Now campaign. Ben refuses to own a driver’s license.
Note the quote “Ben refuses to own a driver’s license”.
Nope, no bias there.
Radiation exposure on the lunar surface during the solar minimum is about 30 Rem annually. But it only requires 10 centimeters of lunar regolith to protect astronauts from heavy nuclei and about 2 meters of lunar regolith to reduce radiation exposure to below 5 Rem per year during the solar minimum.
5 Rem per year is the maximum exposure limit for nuclear workers on Earth.
During the solar maximum, of course, radiation levels would be less than half that.
However, there is a community of over 2000 people on Earth, in Iran, that is naturally exposed to 1 to 25 Rem of radiation annually with no signs of any deleterious physical or reproductive effects.
THE HIGH BACKGROUND RADIATION AREA IN RAMSAR IRAN
http://www.wmsym.org/archives/2002/Proceedings/10/434.pdf
Marcel