Their names sound as if they are part of some science fiction universe: yttrium, dysprosium, samarium, neodymium. They are rare-earth elements (REEs)—little-known but crucial ingredients in much modern US military aerospace technology.
Take lasers. Lockheed Martin is working on a small, high-power laser weapon that the Air Force Research Laboratory wants to test in a tactical fighter aircraft by 2021. Its active gain medium is a flexible optical fiber infused with a rare-earth element such as erbium or neodymium.
Rare-earth elements are widely used in strong, permanent magnets impervious to temperature extremes. They are used in fin actuators, in missile guidance, and control systems; disk drive motors installed in aircraft and tanks; satellite communications; and radar and sonar systems.
As might be expected given their importance to national security, these elements used to come from the United States. From the 1960s to the 1980s, the US was the global leader in rare-earth mining and production.
That is no longer the case.
In recent decades China has become the source of 90 to 95 percent of world rare-earth oxides and the producer of a majority of the globe’s strongest rare-earth magnets…