Lack of Oxygen Lets Metals Cold-Weld in Space, Threatening 1 Stuck Mechanism
Updated
Updated · Livescience.com · Jun 28
Lack of Oxygen Lets Metals Cold-Weld in Space, Threatening 1 Stuck Mechanism
2 articles · Updated · Livescience.com · Jun 28
Summary
Space vacuum lets bare metal surfaces fuse because oxygen cannot rebuild the ultrathin oxide layer that normally blocks atomic bonds on Earth, experts said.
Solar and ionic radiation can scour surfaces clean, while pressure, sliding and vibration shear off existing oxide films and force jagged microscopic peaks into direct metal-to-metal contact.
Cold welding can jam spacecraft hardware—doors, screws and deployable structures—with NASA's Galileo probe a well-known case after its high-gain antenna failed to fully open in 1991.
Gold and platinum are especially prone because they do not form oxide layers, so engineers use anodizing, dry lubricants, dissimilar metal pairings and vacuum-chamber stress tests to reduce the risk.