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Tumbleweed Rover for Marathon Martian Journeys
An anonymous reader writes "A prototype Mars rover, the Tumbleweed, has completed its 40 mile trek across the Antarctic, driven only by winds even in rough terrain over eight days. While the current rovers are designed for flat, equatorial regions, the tumbleweed design is geared to cover longer distances across what many consider the more interesting and dangerous polar regions on Mars."
(dives for cover)
Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
More like anti-escape orb from The Prisoner.
Rover Bowling!
Along the way, the beach-ball-shaped device, roughly two meters (six feet) in diameter, used the global Iridium satellite network to send information about its position, the surrounding air temperature, pressure, humidity and light intensity to a JPL ground station.
Note that the wind-propelled rover used an existing overbuilt satellite constellation to communicate its data back to the engineers. The implication there is that the rover couldn't use the sort of non-androsynchronous communications satellite that is currently available on Mars. So unreliable communications is one notable problem.
Also, look at the data that were being recorded... position, air temperature, pressure, humidity, and light intensity. Position is likely hard to determine without a Martian GPS system. Even so, the rest of those parameters can be deduced from current orbiters, especially "humidity". I can tell you that now -- it's somewhere close to 0%. It's a dry heat^w cold.
The nature of the object means that those are pretty much all the sensor readings you're going to get, too... add pretty pictures to the mix, of course. But this isn't something that can bore holes in rocks or take detailed spectra of interesting spots, because there's no way to anchor the ball to the ground.
If it can be done "fast and cheap", go for it. It might give some good close-up photos of places to send a more capable lander. But I'd suggest launching another Beagle (with airbags) first, if we're wanting best bang for the buck.
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
I suspect it was inspired by this rover.
I built a robot for a class once. And after completing it, I have much more respect for the people trying to design these things.
It's not so hard to make a robot that works. It's all the possible problems that make it hard. And if your robot happens to be on Mars when it breaks... you're SO screwed!
All the little things... unanticipated terrain, sensor malfunction, wheel gets stuck... the list is endless. Of course, during my project I kept to the smooth carpet and just moved the robot whenever something happened. But these guys have got their work cut out for them.
No pressure, its just a 3 million dollar robot!
Slashdot Syndrome: the sudden, extreme urge to correct someone in order to validate one's self.
I would imagine the lack of directional control would make this unit perform very generic atmospheric readings/mapping whatever. What does that solve that an orbiter and beagle type unit combo couldn't?
Or even relatively shallow craters? These would appear to end such missions prematurely. Is the plan, then, to drop multiple such probes (IE, faster/cheaper)?
Roving Web-Teleoperated Robot
The ultra-durable ball reached speeds of 30 kilometers per hour (10 miles per hour) over the Antarctic ice cap
Do you think that someone should tell Astrobiology Magazine that 30 kph is about 18 mph? That's almost double the mph that they give the rover credit for.
"values of beta will give rise to dom!"
For some reason I remember back in the late 1980s the University of Arizona students considered doing something like this. Rather than simply having the wind roll it around, they thought about using pumping fluids. (iirc). They decided against the ball design for fear that it might get stuck somewhere and couldn't get out.
Instead they came up with 'rover' that had two wheels that were inflated in pie sections. It looked like a giant axel with no car attached. It had a nonrotating middle where the instruments, etc, were supposed to be placed. IIRC, they actually tested it out in the desert.
A quick google doesn't turn up anything. IIRC, it was called the 'Mars Ball' and I read about it in Discovery magazine circa 1988, but I might be off +/- a couple years. At the time, I loved it. It was simple, yet seemed rather well thought out and flexible.
Anyone have any good pictures or articles online?
Do you know why the road less traveled by is littered with the bones of the unwary?
I like this part: "[image of] The spherically-wheeled rover [tricycle with 3 ballon wheels] that inadvertently gave birth to the idea for a giant tumbleweed ball. When one of the wheels broke loose during a test, it traveled across the terrain only too well."
Table-ized A.I.
I am not a number, I am a FREE MARTIAN!
THINK
The article says that they wanted to test the durability of the design in a cold environment. That's proven to be a success. Don't start talking about the limitations of the device based on one experiment. The point was to test how well the wind transport design will work, and track its position using a simple, cheap, and pre-existing satelite network. This test is but one test in an ongoing process.
AccountKiller
They are referred to as 'rover' in the series..
Rather scary creatures... Much more so then the orginal 'robot car'that Patrick had envisioned...
---- Booth was a patriot ----
There are many interesting designs that take "unguided" tours of terrain. These include the "tumblers" like the one pictured, as well as a number of "glider" or "floater" designs. The gliders are basically "hover around over a spot and go where the winds take you" approach. They often have a *little* bit of navigation capability (but are mostly at the mercy of winds). The balloon idea is pretty smart. Basically, attach a bunch of sensors along a serpentine "spine" that is attached to a helium balloon. During the day, the balloon warms up and the rover flies to a new destination (wherever the winds take it). Sensors useful in the air (radar, atmospheric, etc.) take over. At night, the helium cools and it touches back down. Sensors useful on the ground (spectrometers, RATs, etc.) now fire up. Brilliant idea because of the simplicity and cost effectiveness.
There exists no way of exchanging information without making judgments. --Bene Gesserit Axiom
Isn't the atmosphere of Mars only a few percent as dense as Earth's atmosphere?
Doesn't seem like the swooshing of the diffuse Martian atmosphere would provide enough force to shove even a highly-engineered tumbleweed around...
This means that it would require a wind about 10x as strong as here to produce the same amount of force on something like this rover.
Fortunately, the gravity on Mars is about 1/3rd of ours, so in theory you'd need only about 1/3rd as much force to move your giant beach ball, so I guess you could get the same amount of movement on Mars as you do here with only 3x as much wind.
(Some more thoughts along this line can be found here, which is a page about a simulated plane flying on Mars.)
Apparantly Mars does have strong winds, so maybe this isn't as crazy as I first thought :)
As an example, the article talks about a 20 m/s wind on Mars -- that would produce the same thrust on a stationary object as a 2 m/s wind would here on Earth -- not very much. But once the object started moving, the thrust would not drop off as fast as it does here (after all, wind won't usually push something faster than the wind is going) so if the ball was light enough, it might actually move at a decent clip. But it would have to be very light.
I vote for the rover in the form of a McDonald's cheeseburger wrapper. This will blow around across half the planet (at least until Val Kilmer's robot dog finds it and eats it)
Don't blame Durga. I voted for Centauri.
First off, to get some of the positional data in a fashion similar to using the Earth's Iridium satellite network, NASA could drop some RF triangulation devices on Mars. This seems like a cheap, viable option to me.
I would think NASA would like to have their "tumbleweeds" stay parked when something fantastic was found. Perhaps the probe could drop anchor now and then. I'm thinking a magnetized metal disc could be dropped outside the ball and attract to an electromagnet inside the ball. When the engineers are ready to let the ball move again, they switch off the electomagnet's current. Given six disposable discs, a ball could be anchored six times and no need for a motor or drilling system.
Also, how about a kite and harness rig? If the ball/probe needs to make a long run, it could have a harness around it attached to an axle running through it. A kite, attached to the harness, would then be launched from the probe and set it off on a faster run than just having air blowing against a ball on the Martian surface. The harness and kite could be dropped if the probe needed to "be free".
BTW, I highly recommend actually reading the links referenced as I am already seeing a lot of duplicate comments here as in previous discussions. Moderators in particular should check those links, unless you like modding up dupes...
In principio erat Verbum.
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For news, status, updates, scientific info, images, video, and more, check out:
(AXCH) 2004 Mars Exploration Rovers - News, Status, Technical Info, History.
That the rovers that go there will move faster than a few feet per day?
That is an exaggeration. The rovers can go at least about 100 feet a day, but often stop to look around or poke rocks. Look how far Spirit has gone. It's lander is little more than a spec in this scene. I bet Opportunity will go even further per day when it moves out of the crater because there are less rocks in the way to study or stump the rover.
Table-ized A.I.
For a real Tumbleweed-type probe more specific hardware would be used. It would undoubtedly take advantage of the martian orbiters that are already in fairly polar orbits (thus the current irregular communications windows). However for now Iridium is cheap, doesn't require extra-paperwork or expensive custom hardware, and frankly they're focusing on the novel bouncy-stuff rather then the rather straightforward comms issues.
Um, no. Again, this is stuff that could trivially and cheaply be tossed onto a proof-of-concept, not specifically what would be included on a Mars-bound probe.However we DON'T know those things about Mars particularly well. Indeed after the rovers landed a bright person figured out how temperatures could be identified for the radio transmission path and it turns out the martian atmosphere is more chaotic with all kinds of thermal upwellings then had been assumed. Getting some widely dispersed numbers of local values would be useful, particularly for confirming assumptions used in interpreting remote sensing guesstimates.
Well, ionization, lighting under clouds, dust volumes, "pretty pictures" of more of the place up close, particularly from non-flat parts, etc. All very valuable. Sure areology is important but there's a lot that can be learned from the surface and ground-level environment that doesn't require drilling holes.For comparison imagine what you can learn just walking down a street with your native senses, information that can't be gained from a spy satellite, particularly one not already calibrated for your environment. Not even manipulating anything you'll learn a lot, be able to infer and correlate a lot more. Sure a Tumbleweed probe is more limited in some sorts of sensing, on the other hand it'll likely be able to go farther and longer then a Beagle-type probe.
The question is what bang you're looking for, and what kinda bucks you can afford.Beagle-type probes can do some things, Tumbleweeds look like they'll be complimentary for others. Is it more valuable to intensely study, and even interact with, a handful of flat places or get measurements of a far wider swath of the plant? At least now we know that we've got alternatives to wheeled carts for exploring.
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
but can a hamster really survive on Mars?
"The problem with internet quotations is that many are not genuine" -Abraham Lincoln
"Oh, look...there went that interesting outcropping we could have explored. Wait, wait...no, wind still hasn't died down. Damn this is the third time around the planet and we still haven't gathered any useful data."
What do you do for solar panels when the thing is round? Could a round panel-covered object still gather sufficient power to run the computers that will be inside, or is the wind supposed to power that as well? Off to read the article... =)
"Beware of he who would deny you access to information, for in his heart, he dreams himself your master."
Nasa's site has a lot more info, especially if you do a search on their site for 'tumbleweed'.
Some early research
Video from June 2001.
J
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For news, status, updates, scientific info, images, video, and more, check out:
(AXCH) 2004 Mars Exploration Rovers - News, Status, Technical Info, History.
Why not make a rover that is sail powered, but with a movable sail that could be lowered in order to stop. The same priciple as a sailboat, but with wheels. The rover would be able to travel long distances with minimal power usage.