A team of researchers at Universidad Carlos III in Madrid has developed a device that works as a windshield wiper to eliminate Mars dust from the sensors on the NASA spacecrafts that travel to the red planet.
The actuator, a type of brush made up of Teflon fibers that are moved by materials that have shape memory, was designed to clean the ultraviolet sensors that were part of the North American space agency's Curiosity mission, although, in the end, the device did not fly with the Martian rover. "In our laboratories, we demonstrated that it worked correctly in the extreme conditions that it would have to endure on Mars, with temperatures ranging between zero degrees and eighty below zero Celsius, and an atmospheric pressure one hundred times lower than that of the earth," explains the head of the project at UC3M, Luis Enrique Moreno, a tenured professor in the Department of Systems and Automatics Engineering.
This device, whose technology will be used to carry out other space missions that are already under way, solves a problem presented by the atmosphere of Mars: the accumulation of iron dust on the flat surfaces of sensors. The Spanish firm Crisa, part of Astrium España, charged UC3M with developing this device, so that it could be built into the Curiosity mission's meteorological station, REMS (Rover Environmental Monitoring Station), which was developed by a consortium of research centers under the direction of the Centro de Astrobiología (CSIC/INTA – Astrobiology Center).
One of the greatest challenges presented by this type of project is to reduce its weight, given that launching any type of material into space is very expensive. Because of this, the design used in this device relied on a type of actuators based on material with shape memory alloys (SMA), a very light nickel and titanium alloy that allows movement when the composite is heated. "The main advantage is that these alloys produce a material that is very strong as related to its weight, that is, a thread of less than one millimeter can lift a weight of 4 or 5 kilograms," states Professor Moreno. "The problem presented by these mechanisms," he continues, "is that, because they are based on thermal effects, they are not as efficient as motor technology, although they are much lighter, which is a very important consideration in space missions."
This group and other research groups at the UC3M are currently working on a second, more elaborate prototype based on SMA technology; it will be used to clean dust from fixed meteorological stations that will be deployed as part of the MEIGA-METNET mission, whose Mars launch is set for the year 2014. "We are also using this technology to develop the exoskeletons used to aid people with mobility problems, trying to substitute motors with these materials, in order to reduce the devices' weight and increase agility in their use," points out Luis Enrique Moreno. According to the researchers, this new product could even be used in the future to improve the joints on the gloves used by astronauts during their excursions out of the spacecraft.
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