Posted by: robotnews | March 22, 2006

Just need the Sun & Wind to travel around Mars

U0204912 Lin Zhiqiang
Explore Mars with Robots

There are a number of limitations and factors that are affecting exploration in distant planets and stars like Mars. One of them is battery life. NASA scientists are always looking for sustainable and renewable engergy sources to run their probes and vehicles that roam around space. The 1997 Sojourner rover was only able to move about 100 meters on Mars in one month and the Mars rover planned for 2003 will travel only about one kilometer during the entire mission.

This can be hardly be called Mars exploration when only such a small area of Mars can be covered. As shown above, surely batteries are not the way to go for space exploration. How about utilizing what is abundant out there – Sunlight and Wind!

A sun-seeking rover and a probe shaped like a giant beach ball are among the newest robots being tested for their potential to explore the Martian landscape.

Basking in the Sun

A robot called Hyperion weaves through hills and around obstacles, all the while avoiding shadows as it calculates a path that maximizes its exposure to sunlight, which it relies on for power. Named for the Greek word meaning “he who follows the sun,” Hyperion was designed and programmed to always point its solar panel directly at the sun.


“What makes Hyperion different is that it is more aware of its surroundings. We have added intelligence to this machine,” said engineer Ben Shamah of the Robotics Institute at Carnegie Mellon University in Pittsburgh, Pennsylvania.

For the past two and a half weeks, Shamah and his colleagues have been testing Hyperion in one of the bleakest and most remote places on Earth—Devon Island, north of the Arctic Circle.
Devon Island, part of the Canadian territory of Nunavut, is uninhabited. Its cold, barren, and rocky terrain is the closest simulation of Martian terrain on Earth. The other advantage of the location is that it has 24 hours of sunlight—perfect for testing this solar-powered robot.
A milestone for Hyperion was completing a 24-hour, 6.1-kilometer (3.8-mile) circuit over hilly, rocky terrain and returning to its starting point with fully charged batteries. One concern had been that the robot would travel too fast or not keep its panels directed toward the sun, causing it to run out of battery power before completing its mission.

Although Hyperion must be further developed before it will be capable of exploring Mars, said Shamah, the current model has demonstrated that “sun-synchronous navigation can provide an unlimited source of energy enabling a rover to explore vast areas.”

Under good conditions Hyperion plods along at about 30 centimeters (one foot) per second. This is a fairly good speed compared to previous battery dependent models. Now lets look at the other energy source that is abudant in Mars and scientists can harness it for their robots’ power.
Blowing in the Wind

Scientists at the Jet Propulsion Laboratory in Pasadena, California, have designed an explorer that can hurtle across the Martian landscape at up to 40 miles (64 kilometers) per hour.
The speedy explorer is a huge inflatable ball about six meters (19 feet) in diameter that is propelled entirely by wind power.

“Mars is very windy but the air is thin, which is why we need to use a big ball—it acts like a huge sail and catches a lot of wind,” said Jack Jones of the Jet Propulsion Laboratory, who is leading the research.
The “tumbleweed ball,” as it is called, carries a payload of scientific instruments at its center, which are held in place with tension cords. Among the instruments is a radar for detecting underground water and a magnetometer for determining the location of tectonic plates. Neither task can be done from an orbiting craft.

The roving ball is also outfitted with cameras, which sit in recessed nooks on its outer surface. When the rover enters an interesting area that merits a closer look, scientists can send a signal to partially deflate the ball and stop it from rolling. When the ball has finished taking measurements, it can be reinflated to enable it to roll onward.

The idea of inflatable rovers is not new, Jones pointed out.
Beach ball-size tumbleweeds, about 0.5 meters in diameter, were tested in the past but abandoned because they frequently became wedged between rocks, making them impractical as remotely operated rovers.

The idea of using a bigger ball came when Jones and his colleagues were testing a robot with three spherical wheels in the Mojave Desert.
“One wheel just fell off and the wind caught it—carrying it up and down, and down and up, the sand dunes,” said Jones. “It must have gone about a mile before we could catch up with it and stop it.”
A tumbleweed ball six meters in diameter is unlikely to get stuck or wedged. It can easily roll over the mostly small rocks that litter the Martian terrain.

One concern the research team has about the tumbleweed ball rover is its lack of controllability. “I hate to admit it, but these rovers are pretty dumb,” said Jones. “They just go where the wind takes them.”
The research team is developing a steering mechanism, which involves shifting the payload off center to force the ball to the left or the right.

Next year, if funding permits, Jones wants to test the tumbleweeds on Devon Island. “There are not many places on Earth where we can just unleash giant tumbleweeds and let them roam around,” he said.

Jones has no doubt that the tumbleweeds will dramatically increase the potential for Mars exploration. The 1997 Sojourner rover was only able to move about 100 meters in one month, he noted, and the Mars rover planned for 2003 will travel only about one kilometer during the entire mission.

“But tumbleweeds,” he said, “could potentially cover hundreds of kilometers per day.”

References:
Hyperion solar powered robot: http://www.spaceref.com/news/viewpr.html?pid=5288
Tumbleweed wind powered robot: http://centauri.larc.nasa.gov/tumbleweed

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Responses

  1. U0300637 Choo Peng Yeow

    First off, I did not know that there were wind in mars… Hahaha….

    Back to the topic, I think that the robot that uses sunlight is rather bulky and looks like several bicycles put together. It looks rather weak and could collaspe anytime.

    Also, although I’m not someone who is very interested in space exploration news, but I think the last robot that was sent to mars for exploration uses solar cell which could mean that it should already be using sunlight as an energy source. At least I know that the robot in the Heineken advertisement does (or is it Carlsberg???)

    As for the robot that depends on wind… How does it control where it is heading??? What if the wind keep blowing the robot into a trench, then it would be stuck inside and never be able to come back to Earth!!!

  2. u0204438 Huang Shichao Alvin

    Somehow I can just imagine a spaceship flying over Mars and unloading a bunch of beach balls that all float gently through the air and bounce all over the place. With the distinctly old-bicycle look of the solar-powered robot, it feels like our “exploration” of Mars is starting to look like we’re just dumping our trash there. =)

    Seriously, looking at where we are now in terms of exploring Mars, we are still a long way from the age of Star Trek and zooming around the galaxy in large spaceships powered by ion drives. Given the short life spans of humans and large distances in between objects in space, conceivably the only way humans will ever get to explore another planet will be to implant a human brain in a robotic body. Assuming the brain can somehow survive, this would solve the problem of the human dying before reaching the planet. All that stands in the way now is the technology, which will come someday soon, and of course, a small question of the ethics involved.

  3. u0303819 Ang Yong Chee

    Well , i thought the article focused more on how the energy required by the exploration robots are generated through the sunlight and the wind .

    I wonder how these robots are actually controlled . Are they self controlled by their AI and possibly “learning ” at the same time .
    Or more practically , are they “manned” by a team of human operators in some control station somewhere ?

    Even so , are there like considerable time lags if the radio signals are to be sent from mars to earth and back? Are the signals able to penerate the mars atmosphere ? or how is the robot to send a strong enough signal to be received back on earth ?

  4. I think this is quite interesting, I felt that the tumbleweeds resemble in some way like the flying saucers stories that we heard about in the past, about UFOs and stuff. Perhaps, over time, the tumbleweeds can be further improved such that it is capable of moving rapidly, not just on the ground, but in the air as well, as long as the contents in the middle can be secured properly.

    The solar panels seem like an ever-present power source for space exploration, but I guess if the ability to track the path with the highest amount of sunlight is good, it would really allow the robot to move fast enough to cover the entire planet in a human life time perhaps?

  5. u0204779 Pang Sze Yong

    “A tumbleweed ball six meters in diameter is unlikely to get stuck or wedged.”

    I find that this statement by the scientists is really ridiculous. What makes them think that a six meters in diameter tumbleweed ball would not get stuck in a 6 meter gap?

    I believe what the scientists should do is modify the tumbleweed ball such that it can change its diameter by inflating or deflating itself to add another 1 meter or reduce by 1 meter its diameter. By inflate itself a further 1 metre (for example) in diameter it can avoid getting stuck in gaps that are 6 meters wide and by deflating itself such that its diameter can reduce by 1 metre, would allow it to become smaller than the gap it is currently stuck in and be blown out by the wind.

    The tumbleweed ball would need to be able to ‘see’ that it is going to be blown into a gap in which it will get stuck and make itself bigger or smaller so that it doesn’t get stuck. This would be a more active kind of solution. A more passive approach would be to let the tumbleweed ball get itself stuck in the gap and when it senses that it is no longer moving, it should shrink itself and by doing so it can hopefully escape the gap.

  6. u0300654 Li Junbin

    Relying on wind for locomotion and solar system for power purpose is a very innovative design. As the world is progressing towards energy-saving route. However, according to the author, more has to be done in terms of controlling the orientation of the “tumbleweed ball” to the desired direction. But i believe that “rolling” will be an ingenious alternative on the top of legged and wheeled locomotion, which can still be explored in many areas.

    Due to scarcity of fuel and other energy resources, solar system has been one of the alternative area of research. This kind of research not only benefit the robotic industry, but also in other significant areas like power electronics industry.

  7. U0204790 Lim Wee Kiang

    Firstly, i think the idea of facing the solar panel to the direction where there is greatest sunlight is a great idea! This perhaps can be incorporated during the periods when the robot’s battery cells are below a certain percentage. The robot stops moving and its cells are optimally charged before the robot gets going again so I certainly am optimistic about the robot being able to last a human lifetime.

    As for the tumbleweed explorer, it is very cool idea with a feasible renewable energy source but like others I am concerned about what if the tumbleweeds get stuck in a trench, or worse still, get sucked into strong cyclone-like winds, and get damaged.


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