On a roll: Designing the next rover to explore Mars

Jun 02, 2010
The new computer model allows engineers to test the attributes of various Mars rover designs, such as those pictured here, before spending the time and money necessary to create prototypes for testing in real-world conditions. Credit: North Carolina State University Space Systems Laboratory

The concept of a wind-powered vehicle that can be used to explore the surface of Mars - a so-called "tumbleweed rover" that would roll over the surface of Mars like a tumbleweed - has been around for more than 10 years, but so far there has been no consensus on exactly what that vehicle should look like. Now researchers from North Carolina State University have developed a computer model that allows engineers to test the attributes of different vehicle designs. This will allow researchers to select the best design characteristics before spending the time and money necessary to create prototypes for testing in real-world conditions.

"We wanted a way to determine how different tumbleweed rover designs would behave under the various conditions that may be faced on the Martian surface," says Dr. Andre Mazzoleni, an associate professor of mechanical and at NC State and co-author of a paper describing the research. "The model that we've developed is important, because it will help NASA [the National Aeronautics and Space Administration] make informed decisions about the final design characteristics of any tumbleweed rovers it ultimately sends to Mars."

The developed at NC State determines how tumbleweed rover designs will function, based on their various design characteristics. For example, the model can show how a rover's diameter, elasticity and overall mass will affect its ability to navigate the successfully.

NASA's Jet Propulsion Laboratory and Langley Research Center are both pursuing the idea of sending tumbleweed rovers to Mars - but researchers are still exploring various options for exactly how the rovers should be designed. "We're optimistic that our model can serve as a mission design tool that can use to choose appropriate design parameters," Mazzoleni says.

"You can't just build hundreds of different rover designs to see what works - it's too expensive," says Alexandre Hartl, a Ph.D. student at NC State who co-authored the paper. "This model allows us to determine which designs may be most viable. Then we can move forward to build and test the most promising candidates."

And the model doesn't just test different rover designs in a stable environment. The model is flexible enough to allow researchers to look at how various designs would perform under different wind conditions and in different terrains - from Martian rock fields to craters and canyons. This is important, because the surface of is marked by significant changes in landscape.

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More information: The research, "Dynamic Modeling of a Wind-Driven Tumbleweed Rover Including Atmospheric Effects," was funded by NASA and the North Carolina Space Grant Consortium. The paper was published online June 1 by the Journal of Spacecraft and Rockets.

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gwrede
3 / 5 (3) Jun 02, 2010
Instead of simulating vehicle designs, they should simply do simulations on where the rover ends up. Simply, put a globe on virtual Mars terrain and let winds blow it around. Sooner or later it will get stuck in a ditch or crater, and that's it. So, unless they plan on releasing hundreds of these on Mars, I see no point in the concept.

Such a "globe-trotter" would travel faster, but with little chance to actively steer it to the interesting sites. So, we'd end up with more data about uninteresting sites, and even less interesting data than the slow-moving rovers.

Besides, the rovers can rove for several years, whereas a globe will get stuck by the fifth storm.
Mayday
2.7 / 5 (3) Jun 02, 2010
One big crater and gulp. It needs backup locomotion. A simple idea would be a releasable anchor and winch. It would be sort of an undo button, for trouble spots. It could also be upgraded with a simple system to fire an anchor out some distance. With two, it could climb hills.

And the entire sphere would need to be quite large not to get hung up on all the smaller, sharp, jutting rocks scattered about.

I love the idea and wish them luck.
Caliban
not rated yet Jun 02, 2010
Large numbers of such a device could collect useful data in aggregate, but I see problems in terms of powering sampling/telemetry eqipment.
Seems like some type of low-bouyancy, near-surface floating sampler would be better, since it would be less liable to capture from terrain.
Long story short- gotta keep the self-powered rovers deployed, in order to have some control over the mission.
antialias_physorg
3 / 5 (1) Jun 02, 2010
I'm asking myself: where's the power source on that thing for its instruments?

Solar panels are out because they would be constantly damaged (or at least smudged) by being dragged over the Mars surface.

Wind energy seems to be not reliable enough (and if you get stuck in the lee of a dune then that's it)

All in all not a very promising concept.

I'd actually favor some form of small airship which will just float to where it wants to go and then descend to take measurements. This would make you independent of the terrain. It would need some power source that could be used to synthesize hydrogen (or another lighter-than-martian-atmosphere-gas) from available sources (either the 'air' or the rocks on the ground) and some way to weather martian storms, though.
JCincy
not rated yet Jun 02, 2010
Instead of simulating vehicle designs, they should simply do simulations on where the rover ends up.


Agreed.

If they send a multitude of these wind driven balls, the pictures sent back from Mars will simply show other vehicles that have collected together at the bottom of crater or pit.
trekgeek1
5 / 5 (1) Jun 02, 2010
I'm thinking American Gladiators. Put a wheeled robot into a sphere made of a lightweight strong material, possibly with a transparent skin on the inside that is structurally protected by the sphere, but protects against dust and small debris. It would be similar to their design but have a tighter spacing on the sphere to accommodate wheels.You get the benefit of the tumble weed, but the control you get from a wheeled rover.
Quantum_Conundrum
1 / 5 (1) Jun 02, 2010
The sad thing is, this is P.H.D. engineers and scientists coming up with this crap.
GaryB
not rated yet Jun 03, 2010
Like the rest say -- these "rovers" will rapidly and efficiently find things on the landscape to get stuck in. Weather balloons would be better.
MarkyMark
not rated yet Jun 03, 2010
The sad thing is, this is P.H.D. engineers and scientists coming up with this crap.

The sad thing is, this is P.H.D. engineers and scientists coming up with this crap.


That is a bit wrong Quantum. This is just a concept idea to test the thesabilaty of the tumbleweed idea. Over time they will [as they refine the design] solve the MANY problems this idea poses such as the power problem. \Just wondering why not supliment solar power with wind by including a small wind turbine in each sail?
MarkyMark
not rated yet Jun 03, 2010
Like the rest say -- these "rovers" will rapidly and efficiently find things on the landscape to get stuck in. Weather balloons would be better.


I agree that floating rovers would be a good idea but i do see 2 problems such as high winds dashing the rover about and even colliding with the ground due to a storm. Also a floating rover might find it difacult to sample soil.
Quantum_Conundrum
1 / 5 (1) Jun 03, 2010
The obvious problem for a floating rover on mars is atmospheric density is too low.

Even with 1/3rd gravity, the atmosphere is only 1/100th as thick as earth atmosphere, so it'd be kinda hard to maintain enough bouancy for a "balloon" type rover.

However, some insect-scale scouting robots might be useful to assist a comprehensive "all technologies included" rover mission in the future. This is because the smaller the scale the greater the surface area per mass, which means a winged insect robot with solar panels sprayed onto it's wings, could probably fly well. Suggested model would be a dragon fly, becaue you can give it a camera in the front, and a decent sized robotic arm for a tail.
ubavontuba
1 / 5 (2) Jun 03, 2010
Okay then, why does the picture accompanying this article (which is purportedly used to illustrate a "computer model") have pine trees in the background? Are they expecting to find pine trees on Mars now?
PPihkala
1 / 5 (1) Jun 03, 2010
How about putting current rover inside a big transparent balloon, like 2-3 meters across? That would probably prevent it from getting stuck onto soil, but unfortunately it would also prevent or make it more difficult to study the ground it's running on. Might also give problems with strong winds.