Rovers have very crucial roles in every mission NASA launches. To prevent a problem similar to the one Spirit encountered on Martian soil nine years ago, scientists are now looking for ways to improve the ability of space exploration vehicles to adopt to challenging terrains on other planets.
At the March meeting of the American Physical Society in Boston, a team of engineers presented the experiments they conducted on robot movement. Their goal was to ensure that rovers on the Moon, Mars and other planetary bodies won’t get stuck in future explorations.
Spirit, nonetheless, beat expectations when it managed to last more than 2,266 Earth days or sols after landing on the Red Planet in January 2004. Scientists initially thought that it would only last 90 days. Its explorations also paved the way for scientists to have a glimpse into the wet history of Mars after it found evidence of carbonate and hematite on the Red Planet.
Considering Spirit’s remarkable discovery and legacy in its six years of active explorations, there’s always that lingering thought on what more it could have uncovered had it not gotten stuck in sand. Because of this, Daniel Goldman’s lab at Georgia Tech in Atlanta is looking into ways to prevent future rovers from meeting the same fate as Spirit.
“You can see that the wheel kept trying to rotate and paddle and sweep, and no matter what it did, it wasn't able to free itself,” Georgia Tech undergraduate student Siddharth Shrivastava said of Spirit’s demise at the recent meeting.
According to Space.com, it’s not just Martian rovers that are at risk of ending their missions too soon because of rough and challenging terrains. Even rovers sent to Earth’s natural satellite are not safe, particularly when they are near the lunar poles where water ice has been spotted.
At the meeting, the team presented new gaits for a proposed lunar rover that would enable the space exploration vehicle to pick up each of its leg and swing it forward similar to how humans take a step. This walking pattern is said to be initiated once the rover has detected a “risky substrate.”
“In the most trivial case, the rover will roll, it will get stuck, and after it's stuck, it will add this legged motion in addition to the rotational motion of its wheels. This gait works pretty well, and it's independent of how deep the rover is,” Shrivastava said.
The team said that after analyzing the experiments they conducted with a mock-up of the rover, the combination of spinning wheels and walking motion is better than just the walking gait. The combination is said to enable a rover to keep moving even at higher inclines. Unlike Spirit and other rovers, however, this approach is bound to actively change the land the rover is exploring because the combination will bring changes to the terrain.
“Essentially, you're intentionally terraforming in order to locomote, which is quite contrary to what Spirit and previous rovers have done, where they're intentionally trying not to model their terrain,” Shrivastava said.
