NASA is developing new robotic gears made from bulk metallic glass (BMG). The specially crafted alloy is built to withstand extreme cold, which is ideal for machines operating on icy planets or moons.
While metal and glass are two fundamentally different elements, the secret to BMG, according to the agency, is in its atomic structure. Similar to how glassblowers manipulate matter to create vases and impress Renaissance Fair crowds, scientists melt then rapidly cool metals to trap their non-crystalline, "liquid" form. This creates what NASA says is "technically a glass," which—when produced in parts greater than 1 millimeter—is called "bulk" metallic glass.
Similar components were first developed in 1960, and have since been used in everything from cell phones to golf clubs, but "understanding how to design and implement them into structural hardware has proven elusive," according to Douglas Hofmann, technologist at NASA's Jet Propulsion Lab in California, who is working with the California Institute of Technology and University of California, San Diego on the effort.
"Our team of researchers and engineers…have finally put BMGs through the necessary testing to demonstrate their potential benefits for NASA spacecraft," he continues. "These materials may be able to offer us solutions for mobility in harsh environments, like on Jupiter's moon Europa."
Initial testing suggests that gears made from BMGs can operate without lubricant, even in extreme conditions (like -328 degrees Fahrenheit). The Mars Curiosity rover currently expends energy simply heating up a grease lubricant every time it needs to move.
"Being able to operate gears at the low temperature of icy moons, like Europa, is a potential game changer for scientists," JPL technology R. Peter Dillon said.
Even better, Hofmann believes BMGs can help reduce the cost of robots that use strain wave gears, which include "a metal ring that flexes as the gear spins [but] is tricky to mass produce and ubiquitous in expensive robots," NASA says.
"Mass producing strain wave gears using BMGs may have a major impact on the consumer robotics market," Hofmann says. "The performance at low temperatures for JPL spacecraft and rovers seems to be a happy added benefit."