January 20th, 2013 by James Ayre
NASA is currently in the early planning stages of an entirely new type of exploration rover. Think “Angry Birds”. The new rovers, which look a great deal like the birds from the popular IOS app, would launch from a mother ship and then swarm the Mars moon Phobos.
The researchers think that the new type of rover is perfect for the extremely low gravity environment of Phobos. And would hopefully give researchers much more insight into the mysterious moon. Not much is known about it, researchers aren’t even clear if it’s a true moon, or a captured asteroid.
The rovers, which are small, spiky, and spherical, will be the backbone of a proposed mission known as the Phobos Surveyor. “The rovers would take advantage of the low gravity on the Mars moon Phobos, its sister moon Deimos, or asteroids in the solar system. Engineers have designed the devices to work in concert with a nearby mother ship.”
“The hedgehogs would work well in the low gravity of the 16-mile-wide Phobos, a force 1,000 times weaker than the gravity on Mars itself, where NASA’s Curiosity and Opportunity rovers currently explore, said researcher Marco Pavone of Stanford University. Gravity on Mars is about one-third that of the Earth.”
“The problem with [regular] rovers is, in low gravity, you don’t have any traction. That means your wheels spin and you do not move,” said Pavone, the primary developer of the mission concept.
Rather than relying on wheels to move around, the new rovers would utilize internal, rotating discs. Currently the plans are for three discs to be encased in every hedgehog. The rovers will measure around 2 feet in total diameter. A prototype of the rover has already been created by NASA.
“The three discs inside a hedgehog point in different directions, giving controllers the ability to move the devices with precision,” Pavone said. “Slightly speeding up the discs can send the hedgehogs tumbling, and a quick spin can make the hedgehog hop to a nearby location,” he added.
The rovers will potentially catch their ride to Phobos inside of the proposed Phobos Surveyor, which NASA officials are considering funding as a Discovery-class mission. What that means is, a roughly $250 million dollar budget, and a fast, streamlined development schedule. Best case scenario, it could launch in about 10-20 years.
The concept isn’t entirely new though. “The exploitation of inertial motion is not entirely new to space exploration, as the Japanese Space Agency’s Hayabusa spacecraft pursued a similar idea. That craft released a small lander while above the asteroid Itokawa.”
“Dubbed MINERVA (for MIcro/Nano Experimental Robot Vehicle for Asteroid), Hayabusa’s tiny lander was supposed to bounce on the asteroid using rotating actuators. But it never made it to the surface.”
The new rover would be a good deal more versatile though, possessing the ability to tumble in addition to the hopping mechanism.
“Pavone’s team has already built two versions of the hedgehogs, but the rovers still require several design changes before they could make it to space. The researchers also plan further testing, including flying the hedgehogs on parabola flights that simulate low gravity, just to see how they behave.”
As it stands, the plan is for 5-6 of the rovers to make the 2-year journey to Phobos, and then to release the rivers one-by-one at different sites.
The mother ship could then remain orbiting, and working to map the moons composition. The mother ship would also serve as the communication hub for the rovers, transmitting their data back to Earth for them.
Image Credits: ESA/DLR/FU Berlin (G. Neukum); Stanford University
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