The Key to Space Exploration may be Better Gears
The next generation of robots will require sophisticated and complex gears. To build these better gears, companies like NASA had to rethink everything.
From the most sophisticated technology to the most basic, machinery is only as good as the components that make it work. That is especially true when it comes to the robotics used in space. And given the huge advancements in the industry, that has caused manufacturers to rethink the way they create components.
Precision robotics only move efficiently when their gears are in working order. Finding high-quality gears that can maneuver in harsh temperatures has been a challenge to scientists for decades, both beyond the Earth and on it. The Second World War had several famous examples of this, especially on the Russian front where frigid conditions brought the Nazi war machine to a grinding halt, allowing the Red Army a chance to reorganize. You can make an argument that the weather combined with a lack of the proper components changed the course of the war, and with it the world.
Gears can become brittle with the extreme cold, and in robotics this can be devastating. Along with the risk of the gears being damaged, a robot may use too much power in an effort to heat the lubricant. That means the robot risks spending its fuel source too early, or it requires more fuel to compensate which adds more weight, and therefore requires even more fuel.
With thousands of pieces and factors needed to make a robot function, even a single flaw can lead to major issues. With robotics looking to play a major role in the exploration and eventually colonization of space, that makes the manufacturing even more vital. For astronauts at least, it may even be the difference between life and death.
The stakes aren’t quite as high, but in order for robots to travel into space and explore, it requires a new type of manufacturing.
Quality can Make the Difference
Using an injection-molding technology, NASA scientists have found a way to manufacture bulk metallic glass (BMG), also known as an “amorphous metal,” into gears that can withstand the temperatures of space. The material is technically glass and can be blow-molded. A similar process is used to make things like smartphones.
When faced with the cold temperatures of space, these high-quality metallic glass gears will not break down like average gears do. The average temperature in space is minus 455 degrees Fahrenheit. Missions can insulate craft and keep them in low power mode while in flight, but they need to be able to operate in brutal conditions.
NASA’s Jet Propulsion Laboratory (JPL) collaborated with Caltech and UC San Diego to test the metal alloy to prove it could work in harsh environments, such as the Jovian moon Europa, where temperatures of minus 260 degrees Fahrenheit (-160 degrees Celsius) are common on the equator.
The Mars Curiosity rover expends energy each time it needs to move just to heat up the lubricant. Durable gears that won’t crack are vital.
The Science Behind BMGs and Injection Molding Technology
When heated into a liquid, certain metals’ atoms lose their organized crystalline structure. To create BMG, the liquid metal is rapidly cooled at 1,832 degrees Fahrenheit (1,000 degrees Celsius) per second to trap the liquid in place.
The atoms remain randomized with a non-crystalline microstructure, also known as metallic glass. When the metallic glass is greater than one millimeter, it becomes BMG. The metal alloy has a low melting temperature, and scientists have found that injection-molding technology works well with BMGs to create durable gears that are less likely to experience teeth fracturing in extremely cold temperatures.
Injection-molding technology now uses the advancement of 3D printing in the manufacturing process of some materials. The advantages of using injection-molding include lower costs, versatility, mass production, stronger parts, reduced waste, use of multiple materials, and fully automatic manufacturing lines.
Strainwave gears, also known as harmonic drives, consist of a metal ring that flex as the gear moves. They are also typically expensive to mass-produce. BMGs can lower the production costs of these strainwave gears, which are necessary for robotics, such as robotic arms that will not shake in humanoid robots.
It is a complex process to create the pieces that make up even more complex machines. It’s also a necessary one.
The Future of Robotics is Better Gears
In the consumer world, bulk metallic glass has been around since 1960 and is in products all over the world. The science of using BMG to mold strainwave gears, however, is new and opens up possibilities in the robotics field and aerospace.
BMG gears can run smoothly at temperatures of -328 degrees Fahrenheit without lubricant. With the new BMG gears requiring less heated lubricant, missions can preserve battery power.
Due to lower production costs, companies will be able to mass-produce strainwave gears made from BMGs for consumer products on Earth, as well as necessary robotics aimed for space exploration. The next step is to design and test the gears for planetary gearboxes. We are one step closer to the reality of deep space exploration as scientists continue to investigate and solve these technological problems.