The Spirit rover got stuck in a patch of sand on May 1st, 2009, after five years on the Martian surface. NASA officials declared that the Opportunity rover had ended its mission after a planetary dust storm forced it into hibernation. The wheels of the rover showed signs of wear in March of last year. Sending rover missions to other planets to look for discoveries that can lead to scientific breakthrough is a risk.
What is an acceptable risk for a robotic mission, and when should mission controllers take them? The new approach for weighing the risks against the scientific value of sending planetary rovers was developed by a pair of researchers from the Robotics Institute. Future robotic missions to the Moon, Mars, and other potentially hazardous environments in the Solar System will be implemented by the researchers.
David Wettergreen is a research professor at the RI and a data scientist at NASA. The paper that describes their approach was presented at the International Conference on Intelligent Robots and Systems in Kyoto, Japan.
Scientific value is measured by the mission's confidence in interpreting mineral data. It might decide to explore somewhere else if it concludes that it has identified the mineral composition of rocks. It might decide to study the current area to improve its accuracy if it's low. The models wettergreen and Candela combined weighed the scientific value of the region against any potential dangers to the rover.
According to a NASA press release, Wettergreen has worked on autonomously planetary exploration for decades.
“We looked at how to balance the risk associated with going to challenging places against the value of what you might discover there. This is the next step in autonomous navigation and to producing more and better data to aid scientists.”
Wettergreen and Candela used a model to determine how difficult it will be for the rover to get to its destination. There is a high level of risk associated with sloped terrain with loose sand, as the rover might cause a slide if it attempts to ascend the slope. When the Spirit rover got stuck in a dune in 2004, its wheels slipped as it tried to move.
The team used a simulation to test their framework. They used a simulation rover to navigate through the terrain and evaluate the scientific obtained from the missions. The rover did a good job on its own. There were still lots of areas for the rover to explore even under high-risk simulations.
Researchers have proposed and demonstrated methods that would allow rovers to navigate across the surface of other planets in the 1980's. The six-meter tall, six-legged robot that was tested in the 1990s is included. The robot demonstrated how rover missions could prioritize their goals and chart their own paths.
Ratler is a four-wheeled, skid-steered robot that is being used as a testbed for lunar navigation software. In the summer of 1997 there was a demonstration rover called Nomad. There was a project led by Wettergreen that built a rover that would follow the sun to keep its batteries charged. The Zo rover has been used as a testbed by researchers since 2004.
The method was developed by Wettergreen and Candela. Zo traveled hundreds of kilometers to test systems in the Atacama Desert. The rover decided to drill at a site that led to the discovery of highly-specialized microbes in order to demonstrate how a system like that can result in valuable scientific returns. They hope to use Zo to test their new method in the Utah desert. As Wettergreen stated.
“Our goal is not to eliminate scientists, not to eliminate the person from the inquiry. Really, the point is to enable a robotic system to be more productive for scientists. Our goal is to collect more and better data for scientists to use in their investigations.”
They think that their research could be useful to future lunar exploration, including NASA's long-awaited return to the Moon. Before sending crewed missions to the lunar surface, robotic missions need to investigate the local terrain, scout resources, and assess potential dangers to astronauts. Wettergreen and Candela's new approach could be used to map out potential routes in advance and balance the risk of traveling them with the potential for major scientific finds.
Next- generation rovers sent to distant locations could benefit from their approach. Evidence of life beyond Earth can be found on bodies such asEuropa, Titan, and others. Mission controllers would no longer have to focus on scientific data when interpreting missions close to home.
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