Superconductors

Once-famous superconductors may be about to step back into the limelight.

The audience awaits

The special "talent" of superconductors is that they have zero resistance to electric current. Absolutely none. In theory, a loop of HTS wire could carry a circling current forever without even needing a power source to keep it going.

In normal conductors, such as copper wire, the atoms of the wire impede the free flow of electrons, sapping the current's energy and squandering it as heat.

Today, about 6 to 7% of the electricity generated in the United States gets lost along the way to consumers, partly due to the resistance of transmission lines, according to U.S. Energy Information Agency documents. Replacing these lines with superconducting wire would boost utilities' efficiencies, and would go a long way toward curbing the nation's greenhouse gas emissions.

MRI scans, a powerful tool for medical diagnosis, use superconducting electromagnets to generate detailed images of body tissues. Most of today's MRI machines require expensive liquid helium to cool their low-temperature superconducting wire.

The fledgling "maglev" train industry would also welcome the availability of higher-quality, cheaper HTS wire. Economic realities stalled the initial adoption of maglev transit systems, but maglev development is still strong in Japan, China, Germany, and the United States.

NASA is looking at how superconductors could be used for space. For example, the gyros that keep satellites oriented could use frictionless bearings made from superconducting magnets, improving the satellites' precision. Also, the electric motors aboard spacecraft could be a mere 1/4 to 1/6 the size of non-superconducting motors, saving precious volume and weight in the spacecraft's design.

Should we ever establish a base on the moon, superconductors would be a natural choice for ultra-efficient power generation and transmission, since ambient temperatures plummet to 100 K (-173 C, -280 F) during the long lunar night - just the right temperature for HTS to operate. And during the months-long journey to Mars, a "table top" MRI machine made possible by HTS wire would be a powerful diagnosis tool to help ensure the health of the crew.