Wall-Climbing, Gecko Robot Could Scuttle in Space
The six-legged Abigaille climbing robot clings to surfaces using a gecko-inspired dry adhesive technology.
A wall-crawling robot inspired by the gecko has taken a small but important step towards a future in space, scientists said on Thursday. The tiny legged prototype could be the forerunner of automatons that crawl along the hulls of spacecraft, cleaning and maintaining them, the European Space Agency (ESA) said.
Its footpads are covered with dry microfibers modeled on the toe hair of the gecko, which is celebrated for its ability to scuttle up windows and along walls yet not leave a trace. The lizard does the trick through millions of ultra-fine hairs called setae, which interact with the climbing surface to create a molecular attraction known as the van der Waals force.
Researchers at Canada's Simon Fraser University first built a 240-gram (eight-ounce) tank-like gecko-bot, using tracks with microfiber treads. They then developed this into a six-legged climbing robot, nicknamed Abigaille.
"This approach is an example of biomimicry, taking engineering solutions from the natural world," said team leader Mike Henrey.
The "dry adhesive" that helps Abigaille climb walls has now been put through its paces at a materials-testing lab at ESA's European Space and Technology Center in Noordwijk, the Netherlands. Replicating the vacuum and temperatures of space, but not the zero gravity, the tests found that the adhesive worked like a charm, the agency said.
"A depth-sensing indentation instrument was used inside a vacuum chamber to precisely assess the dry adhesive's sticking performance," ESA specialist Laurent Pambaguian said in a press release." Experimental success means deployment in space might one day be possible."
Abigaille's six legs each have four degrees of freedom, which enables the "gecko-bot" to shift from horizontal to vertical environments. Dry adhesives in space are compelling because other options have to be ruled out for safety reasons. Sticky tape is a no-no because it collects dust, becomes less sticky over time and in a vacuum gives off fumes.
Magnets, too, are out as they cannot stick to composite surfaces and their magnetic field could affect instruments. And Velcro is also excluded, as it needs a mating surface of hooks -- and these can break off and become a hazard.
Gecko setae are microscopic: their ends are just 100 to 200 nanometers, or 100 to 200 billionths of a meter, across. By comparison, the human hair is gigantic, being around 100,000 nanometers in diameter.
"We've borrowed techniques from the micro-electronics industry to make our footpad terminators," said Henrey. "Technical limitations mean these are around 100 times larger than a gecko's hairs, but they are sufficient to support our robot's weight."
Abigaille can transition from vertical to horizontal surfaces in the vacuum conditions of space.
'Selfies' are all the rage these days. Every smartphone is attached with a camera and to the Internet, so it was inevitable that our vain species would take full advantage of the technology, snapping endless photos of cats and, of course, ourselves. Selfies -- or 'self portraits' to the uninitiated -- have become such a cultural phenomenon that Oxford University Press has declared 'Selfies' their word of the year. This may sound asinine, but Merriam-Webster Dictionary balanced it out
. In the spirit of fairness, I've combined the two words of the year and applied them to robots. Yes, robots. Robots that explore space, doing science. And just in case you didn't know, robots can be pretty vain too, taking snapshots of their junk for the whole Internet to see. To narrow the field down a bit, I've only selected robots that have photographed parts of their own structure, or attached components. I've also allowed the occasional robotic camera that was deployed for the sole purpose of taking a selfie
(nice effort, IKAROS).
The first robot that likely comes to mind is the undisputed
King of Selfies
, NASA's Mars Science Laboratory rover Curiosity. The car-sized rover impressed the world with its selfie prowess when mission scientists released a stunning high-resolution mosaic of the rover in November 2012, only a couple of months after it landed inside Gale Crater. Curiosity achieved the feat by holding its Mars Hand Lens Imager (MAHLI) at (robotic) arm's length, taking a truly authentic "selfie." The world applauded this effort.
But Curiosity certainly wasn't the first robot on Mars to snap its own picture, and it won't be the last. Although the Viking landers that touched down on the Red Planet in 1976 didn't have robotic arm-mounted cameras capable of taking a "true" selfie, they did their best.
from Viking 2 was snapped on Nov. 2, 1976, showing a part of the lander's deck, the American flag, the bottom of the robot's high-gain antenna and a boulder-littered Utopia Planitia, the largest identified impact crater on Mars.
Staying on Mars, some amazing panoramic shots and top-down self portraits have been attained by NASA's epic twin Mars Exploration Rovers Spirit and Opportunity. As you've probably guessed, commanding a robot on another planet to take self portraits isn't for fun (even though the outcome
a lot of fun), it actually serves a purpose. In the case of Viking and Curiosity, engineers on Earth can study the photos to see the condition of instruments on the robots' 'decks.'
, for solar powered rover Spirit, using its mast-mounted panoramic camera was very useful for capturing amazing 360 degree views of the surrounding terrain. It was also great for keeping track of the build-up of Martian dust on its panels. In this photo taken in 2005, Spirit's solar array shines in the sun, having collected only a very thin layer of dust two years after it landed.
Spirit's twin rover Opportunity soldiers on to this day, exploring the Martian surface after nearly a decade since landing. Jan. 25, 2014, is its 10 year Mars "birthday" (mark your calendars!). Currently exploring the edge of Endeavour Crater, helping to piece together clues of Mars' evolution (complementing the science being done by Curiosity), Opportunity is no stranger to taking its own photo. As Spirit and Opportunity were designed to the same specifications, Opportunity can also take 360 degree views and monitor dust build-up on its solar panels.
in 2011, its once shiny solar array is blanketed with a camouflaging coat of dust.
No, robotic Mars explorers aren't especially fond of sefies, it's just that NASA has sent a lot of Mars surface missions in the past few years. Seen here in 2008, NASA's Mars arctic lander Phoenix took its own photo using a mast-mounted panoramic camera in a similar style to Spirit and Opportunity. It seems that the first rule of robotic selfies is: If it ain't broke, don't fix it.
Now for something a little different. In 2007, the European comet-chasing spacecraft Rosetta made close approach with Mars, coming within 1,000 miles of the surface, using the planet for a fuel-saving gravity assist. The boost in speed is allowing Rosetta to catch up with comet 67P/Churyumov–Gerasimenko -- an encounter that is planned for 2014. But during the flyby, the spacecraft managed to snap this iconic photo of Mars from space. What makes
so special is that Rosetta also caught its own solar array in the shot.
Leaving Mars, we now head to Venus where, in 1982, the Soviet Venera 13 lander managed to survive the hellish conditions and transmit data for two hours. In that time it also returned some color photos of the Venusian surface. In those photos, the hardy lander was able to capture some of its jagged landing gear at the bottom of the shot. It may not be perfect, but while sitting in a pressure-cooker with a limited amount of time to return valuable data, it's a superb effort.
In a video released by the Chinese Space Agency of the Chang'e 2 lunar orbiter in 2010, the view shortly after launch was captured by a camera overseeing the deployment of the mission's solar panels.
, the video in its entirety
Whoa! What's that huge UFO that photobombs the shot?
Oh, that's Earth.
The Japanese Hayabusa asteroid sample return mission got a little creative with this selfie effort. In 2005, as it approached near-Earth asteroid Itokawa, with the sun at its back the mission snapped its shadow falling on the sunlit asteroid surface.
for leading me to Hayabusa!
In 2010, the Japanese space agency JAXA launched a pioneering mission. Using only the sun's energy for propulsion, the Interplanetary Kite-craft Accelerated by Radiation Of the Sun, or IKAROS, probe set sail through interplanetary space for a January 2011 rendezvous with the planet Venus. After the solar sail was launched, two miniature wireless cameras were ejected by IKAROS as it deployed in Earth orbit,
. Then, as IKAROS reached its destination eight months later, it took a snapshot of a crescent Venus (inset). (Thank you
for reminding me about these stunning IKAROS photos!)
Special thanks to all my Twitter buddies who engaged in Wednesday evening's conversation about robot selfies!
Can you think of more space mission "selfies"? Feel free to share them in the comments below.