A NASA project is developing special gears that can withstand the extreme temperatures experienced during lunar missions and beyond. During NASA's Artemis missions, temperatures at the Moon's South Pole will drop drastically during the lunar night.
Farther into the solar system, on Jupiter's moon Europa, temperatures never rise above minus 162 degrees Celsius at the equator. Typically, in extremely low temperatures, gears - and the housing in which they are encased, called a gearbox -- are heated.
Gearboxes That Can Survive Extreme Cold
After heating, a lubricant helps the gears function correctly and prevents the steel alloys from becoming brittle and, eventually, breaking. NASA's Bulk Metallic Glass Gears (BMGG) project team is creating material made of "metallic glass" for gearboxes that can function in and survive extreme cold environments without heating, which requires energy.
Operations in cold and dim or dark environments are currently limited due to the amount of available power on a rover or lander. The BMGG unheated gearboxes will reduce the overall power needed for a rover or lander's operations, such as pointing antennas and cameras, moving robotic arms, handling and analyzing samples, and mobility (for a rover).
The power saved with the BMGG gearbox could extend a mission or allow for more instruments. The team recently tested the gears at NASA's Jet Propulsion Laboratory in Southern California where engineers mounted the motor and gearbox on a tunable beam designed to measure the response an item has to a shock or forceful impact.
Making Sure of Quality
Team members then used liquid nitrogen to cool the gears down to roughly to minus 173 degrees Celsius. Next, they fired a cylindrical steel projectile at the beam to simulate a "shock event." "Before NASA sends hardware like gearboxes, particularly those made with new materials, to extremely cold environments, we want to make sure they will not be damaged by the stressful events that occur during the life of a mission," Peter Dillon, BMGG project manager at JPL, said in a statement.
"This shock testing simulates the stresses of entry, descent, and landing, and potential surface operations." The motor and gearbox were shocks tested twice in three different orientations. Each test demonstrated that the gears could withstand a "shock event" at a temperature as low as minus 173 degrees Celsius. NASA Artemis program will land the first American woman or the next man on the lunar surface by 2024.
