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Mars Rover: Tumbleweed Models
An anonymous reader writes "A North Carolina State project has prototyped a wind-blown Mars exploration rover. It draws its inspiration from the lowly tumbleweed, to cover large distances with low-power requirements. For collecting atmospheric, thermal or geological samples across great distances, the 'single-wheel' tumbleweed has some advantages over the usual four-wheeling approach to tough terrain."
I quickly read over the article, and I failed to see any reference to direction of this thing. Now, it would seem to me that it could get blown into a place that it could not get out of. Without some sort of steering mechanism how do they ever plan to work this thing? And of course, since there are no GPS satellites around Mars they couldn't even determine the location, especially if it was picked up by the wind or something. It sounds like a good idea in theory, but it seems to me that the data would be nearly irellivent without positional data to accompany it.
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This is an interesting idea.... but its entire basis for movement -- the wind on Mars -- seems to limit its usefulness to gathering data only on the areas of Mars where winds blow the strongest. Not that there isn't valuable information to be gathered there, but aren't windy areas somewhat of a scientific dead-end? I mean, if this thing ends up following the prevalent wind currents, wouldn't it just sort of follow a relatively smooth path worn away by centuries of wind erosion? The "juicy bits" of Mars are those that have been left more or less untouched for millenia -- those are the areas that give us the greatest insight into the history of the planet... which are precisely the areas that this thing won't be blown to -- and I suspect, where one would find just the sort of rough terrain this probe is built for. Wind has a bad habit of mixing things up -- ie. are these mineral samples native to the area, or have they been carried from the other side of the planet by this wind system?
Optical mouse technology might be the key in atleast determining speed. Assuming there is enough in the way of magnetics on mars, atleast some means of determining direction, in conjuction with an altermeter to determine it's relative height based on known factors. And provided you did some form of arial recon to verify it's position in reality at any given time, the location of such a device can be determined on a planet and (just about) any given time, assuming you have adquate maps to begin with.
Steering, or some form of manual control to actually get this device into or out of a specific location seems somewhat vague to me... but one *could* do it with gyros.
Seems like a great means of getting a land scanner about, provided you happy with where the wind takes you.
There is no sanctuary. There is no sanctuary. SHUT UP! There is no shut up. There is no shut up.
This thing can move around easily and efficiently - fine. But how are we supposed to make it go where we want to go? On Mars, with its sandstorms, etc, control would probably be vital. OTOH, these could be deployed en masse and just keep beaming data back - durable, mobile, sensors.
By knowing the landing location, you can extrapolate where you have gone if you have am original bearing and known travel direction.
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A link about things like this:
http://www.nasatech.com/Briefs/Nov01/NPO21235.h
Also you could remote view it if a non landing craft kept track of it
On the other note, the winds are lacking on mars:
Perhaps a solar wind collector?
http://science.nasa.gov/headlines/y2001/ast31ja
If you could put 50 of these things down at once, scatter them around.... (They are terribly light-weight, right? Supposed to be blown around by the thin martian wind?) You sprinkle them on mars from orbit, and they expand to catch the wind for re-entry. They bounce a few times, then start tumbling along.
So what if a few get stuck in a crevasse here and there? As far as location tracking, I'd assume they would each have their own radio frequency, and the orbiter would only be able to pick them up when it was over the horizon. Shouldn't be too terribly hard to get a rouch idea where the thing is. (Data sent back from the probe, compared against current mapping images ought to tell the rest of the story)
I like this idea better than building one (or two) big clunky rovers that have a 50/50 chance of surviving Nasa's re-entry math.
That kind of makes me nervous. I don't really like the idea of any sort of "seed" probing like that. For one, it seems like an invasion of sorts. Two, its a recipe for spreading bacteria all over the planet -- despite NASA's stringent cleanliness, the fact of the matter is that some bacteria CAN survive space flight and reentry -- if that happens, and 20 years after we send these things to fly willy-nilly around Mars, how can we tell if these bacteria or whatever are originally from Mars or from Earth? It just seems a wee bit risky to me. *shrug*
This kind of thing has been done since the 1960s at NASA's JPL. See http://www.jpl.nasa.gov/adv_tech/rovers/tmblweed.h tm
SegFault
Seriously, you don't need to control it. After all, you would get much more data if this thing would last for years being blown in random locations then say....the rover having limited access next to base an only lasting for a short period of time. In the end, it amounts to data and cost effectiveness of getting it. I'm all for this concept.
Life is not for the lazy.
This is smart, off-the-wall thinking.
Exactly the kind of thing NASA needs these days.
...until it gets stuck in a fence or run over on the interstate.
Good judgment comes from experience, and a lot of that comes from bad judgment.
Kinda weird, but the article claims that "While working as a 2002 summer intern at NASA Langley, team leader David Minton initiated the idea to study a "Mars Tumbleweed" for the class project." Well, that'd be all great and everything if JPL hadn't already come up with the idea: Exploring Mars: Blowing in the Wind?. The JPL article is dated August 10, 2001.
Someone probably should have told David Minton about Jack A. Jones' research at JPL. "Jack A. Jones...is leading JPL's research into various inflatable machines for exploring space. JPL's Inflatable Technology for Robotics Program aims to create rugged, all-terrain vehicles and other devices with low mass and low-packing volume."
Either these are geniune female geeks...
or these guys have groupies!
Picture here and here!
Now I respect their project!
AC
if bacteria can survive in space then it would already be there. the earth is already "contaminating" the solar system with spores. What, you think a bacteria spore is actauly stuck in our gravity well? No. stuff is leaveing our planet all the time. Now I don't know if it would grow on mars or any where else....that has yet to be discovered.
So please take you psuedo space enviornmentalism and shove it where the sun don't shine.
She doesn't seem to mind.
NASA girls rock.
I think there is a slight problem, because the Mars surface isn't really that flat like the deserts on earth. There are lots of cracks, mountains and just bottomless pits. Not that ideal a hunting ground for a probe that essentially can't be steered in any predictable way.
So I imagine they would either have to choose the landing site very precisely (even if successful the rover probably wouldn't have much room to travel until it gets stuck somewhere) or the other approach might be to deploy not one but more of those probes so you can count on the probability of at least one getting far enough to be efficient.
Keep in mind, we're talking NASA here, it would be ridiculously expensive to put anything up there. So why not build probes that can really be controlled (or at least be able to control themselves) while youre at it?
Couldn't they try a cluster bomb approach? have tiny little sensors communicating to a main section using radio. When the device is falling into the atmosphere, these sections could be ejected over a large area.
Donkey years ago, I read a book by Heinlein where one of the Martian creatures was modeled on a tumbleweed. Art inspires science again.
Every University round the globe that has an even remotely competent Aeronautical/Mechanical/Electronics/CompSci/Vision department, takes part in a "Mars Rover" project, funded by xyz.
So, what's so differne about these folks, that necessitates (correct spelling? I doubt it) front page status?
/. Where the truth
Design the tumbleweed sphere with a helium bottle inside. Add a valve to vent the helium to the outside. If there has been no detected movement of the sphere for a day or two, inflate with helium until it attains slightly positive bouyancy. Drift off for a few hours and then open the vent, settling back to the ground. Let the wind blow it around in tumbleweed mode until it stops.
Rinse.Repeat.
You were 80% angel, 10% demon. The rest was hard to explain. - Over The Rhine
"Math in a song is good."-Linford
I don't really like the idea of any sort of "seed" probing like that
/.
Too late; it's been going on for a couple of billion years already.
In the 1960's (and probably earlier) a number of astronomers did detailed studies of the Earth's dust tail, which is formed by the solar wind blowing off the outermost atmosphere. It's pretty thin, but it's thick enough that it interferes with some sorts of astronomy.
They basically reported that the Earth's tail does contain particles of dust up to the size of bacterial spores. Tests had already shown that many bacterial spores can survive for long periods in space, the conclusion was obvious: The Earth has been spraying the outer solar system with bacterial spores for as long as bacteria have been making airborn spores, probably several billion years.
So there is life on all the outer planets in the solar system, and it came from Earth. Whether any of those spores can survive elsewhere isn't known. But conditions on Mars are not all that dissimilar to conditions in the dry valleys in Antarctica, and some bacteria do survive and grow there. So it's possible that some of the bacteria from Earth are surviving and growing there, though probably not very well. OTOH, some have been there for a couple billion years, so there has been time for natural selection to do its thing.
Some of the astronomers also pointed out back then that the Earth's dust tail doesn't stay within the solar system. It eventually reaches interstellar space. Considering that the Earth orbits the galaxy about 4 times per billion years, and bacteria have been here for around 4 billion years, the dust tail of Earth has pretty much permeated the galaxy with spores. Similar calculations would apply to any other Earth-like planet in the galaxy.
This sort of calculation is part of the basic of the "panspermia" hypothesis that has gotten a bit of discussion in some circles. Of course, it's a bit difficult to collect real evidence on such a topic.
But if we do find living bacteria on Mars or Titan that have chemistry similar to bacteria on Earth, it will be weak supportive evidence.
This isn't the first time this topic has come up on
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
NASA-Langley had a section of the "science" building at the State Fair in Richmond, VA last year, and invited both civil servants and contractors (like me) to help man it. One of the displays, which I was at, was a large aquarium tank with a fan attached to one end, and little rocks and sand and junk cemented to the bottom to simulate the Martian landscape. I had six different models of potential "tumbleweed" craft, designed by schoolchildren, that you would drop into the tank and see how well it tumbled. The fan speed was low, MUCH less than some of the crazee whirlwinds on Mars, and pretty accurately approximated the volume of air moving given the much greater air density on Earth.
The only model that consistently tumbled over half the length of the tank was a small Styrofoam ball, with wooden sticks poked into it with little plastic discs attached to the ends of them. It had the most outside surface area of any of the models.
They also had a full-scale model of the Sojourner robot. That was cool. It looked expensive.
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As far as steering, several options I remember hearing their team members discuss throughout the year were actuating the planar sails on the inside of the carbon fiber ribs, some sort of anchor for times when prevailing winds were in unfavorable directions, and changing the mass distribution and inertial characteristics. However, I think the point is that they wanted a simple, lightweight, easily reproducible design; the whole idea of a tumbleweed is based on utilizing what you don't have to bring along (interestingly enough, it was first thought of when a test rovers wheel blew away and escaped the crew out in the desert, I believe).
I remember their presentations mentioning research they did on the atmosphere and typical wind climate, average surface qualities (rock size, etc), and how it would affect their design. The biggest concern I heard judges from industry at the southeast AIAA student conference (http://www.AIAAstudentconference.org) echo was over oddly shaped debris gathering inside the design and weighing it down.
The pictures you see on their website are from the senior design picnic less than a month ago. The actual design is even larger. The wind was calm, but it would only take about a 10 knot gust to start rolling. And yes, the girls in the pictures are real engineering students, and I know them all- don't worry, they're a lot smarter than to let you guys explore any surfaces. But I'll let them know you brought it up. Also, Dustin isn't copping a feel. I think his family was a few yards outside that picture, but it does look sort of funny.
If anyones curious, look up our design project too (http://www.mae.ncsu.edu/courses/Mae478-479/team3/ webpage/frameset.htm)
on a hopefully soon-to-be autonomous 200 knot jet aircraft (pretty decent for
~12 lb. thrust). The section pages are still empty, but there are lots of pictures
and a couple videos.
Question: how difficult is it to put satellites into geosynchronous (or Areosynchronous
and 2), I'm a bit ignorant of the calibration methods for GPS. Just how would the three Martian satellites get their position calibrated? Drop a retro on the planet's surface or something?
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