Description: 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 the 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 return 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 extreme temperatures ranging from -220°C on Europa to 462°C on Venus, and environmental pressures ranging 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 are therefore necessary to simulate relevant environments to mitigate mission risk. In Phase-I and Phase-II of this proposal, the team has developed a compact high temperature high pressure tribology test chamber simulating Venus conditions and tested tribo-pairs giving insight on the friction and wear behavior. Polymeric coatings were tested under lunar and Mars’ extreme abrasive temperature conditions proposing a possible solution. This proposal offers further development of the solution for these extreme conditions: 1. Long term durability test under 2.4 MPa/350 PSI CO2 pressure at 462 ℃. high temperature (HT) high pressure (HP) tribometer; 2. ATSP coatings’ rolling contact tribological performance with Lunar dust conditions; rolling bearing design recommendations by using ATSP coatings.

Benefits: We foresee several applications relevant for NASA's planned and future mission needs: 1. Verified tribo-pair for mechanical devices on Venus probes for the high-temperature and high-pressure requirements. 2. ATSP-based materials for abrasive Lunar and Mars conditions sealing, dust mitigation and rolling bearing applications. 3. ATSP material for sealing applications, especially in dynamic condition, this will give durable and reliable bearing material solutions for future hydrogen and oxygen storage (from electrolyzed water) in Mars.

A broad spectrum of users in the energy and industrial sectors may benefit from these advances towards part lifetime and reliability: 1. ATSP composite for precision liquid transfer and high-pressure fluid sealing applications: wear rings, components in the compressors, valves, pumps. 2. Hydrodynamic tilting pad bearing applications to extend the service life and reduce maintenance cost.