Extreme Environment Tribological Characterization of Advanced Bearing Materials

This proposal addresses subtopic S4.04 Extreme Environments Technology and specifically interest in long life bearings, tribological surfaces, and lubricants. NASA is expanding its ability to explore deep atmosphere and surface of gas giants, moon surfaces, asteroids, and comets through use of long-lived balloons and landers. Dragonfly will launch in 2026 and arrive in 2034 on Titan. Future Mars missions will returnnbsp;samples from the surface of Mars to Earth. The Artemis program will land humans on the Moon by 2024. Conceptual landing probes for Europa and Venus have been proposed. These missions will experience extremenbsp;temperatures ranging from -220deg;C on Europa to 462deg;C on Venus, and environmental pressures rangingnbsp;from vacuum on the Moon to 9.3 MPa on Venus. At these extreme atmospheric conditions, traditional oil lubricants and greases are infeasible, resulting in dry sliding conditions with detrimental effects on component performance. Tribological experiments arenbsp;therefore necessary to simulatenbsp;relevant environments so as to mitigate mission risk. This proposal offers unique solutions for these extreme conditions:We will develop a compact high temperature (HT) stage for an existing high pressure (HP) tribometer - providing a unique capacity to simulate wear and friction onnbsp;Venusnbsp;(462deg;C and 9.3MPa gas pressure)ATSP coating vs. ATSP coating has low coefficient of friction (COF) and ldquo;zero wearrdquo; from -196deg;C to 300deg;C. This excellent tribological performance leads us to introduce ATSP-based coatings for Lunar and Marsrsquo; abrasive conditions and wide thermal demands.nbsp;We further proposenbsp;use of this coating to resolve wear issues for a cam-follower tribo-pair in the rotary-percussion drill for the Titan Dragonfly mission.For hard coatingsnbsp;in Phase II, tribo-pairs for Venus conditions will be identified by doing tribological study for tribo-pairs, including PS400 vs. Inconel and PS400 vs. DLC, under Venus simulating conditions: 462deg;C and 9.3MPa 96.5%CO2 + 3.5%N2