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NASA Science News for February 5, 2003

Living up to the Hype: Superconductors
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NASA research is unlocking the amazing potential of high-temperature
superconductors. 

February 5, 2003:  Few technologies ever enjoy the sort of rock-star
celebrity that superconductors received in the late 1980s. 

Headlines the world over trumpeted the discovery of "high temperature" 
superconductors (abbreviated HTS), and the media and scientists alike 
gushed over the marvels that we could soon expect from this promising 
young technology. Levitating 300-mph trains, ultra-fast computers, and 
cheaper, cleaner electricity were to be just the beginning of its long 
and illustrious career. 

Today we might ask, like a Hollywood gossip columnist: what ever
happened to the "high-temp" hype? 

"It was the hottest potato of its time, but it all fizzled out," says
Louis Castellani, president of the Houston-based HTS company Metal
Oxide Technologies, Inc. (MetOx).

The problem was learning to make wire out of it. These superconductors 
are made of ceramics--the same kind of material in coffee mugs. 
Ceramics are hard and brittle. Finding an industrial way to make long, 
flexible wires out of them was going to be difficult. 

Indeed, the first attempts were disappointing. So-called "first
generation" HTS wire was relatively expensive: 5 to 10 times the cost
of copper wire. Furthermore, the amount of current it could carry
often fell far short of its potential: only 2 or 3 times that of
copper, versus a potential of more than 100 times. 

But now, thanks to years of research involving experiments flown on
the space shuttle, this is about to change. 

The NASA-funded Texas Center for Superconductivity and Advanced
Materials (TcSAM) at the University of Houston is teaming with MetOx
to produce the "smash hit" that scientists have been seeking since the 
'80s: a "second generation" HTS wire that realizes the full 100-fold 
improvement in current capacity over copper yet costs about the same 
as copper to produce.

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.

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. 

Worldwide, the current market for HTS wire is estimated to be US$30
billion, according to Castellani, and it is expected to grow rapidly. 


A backstage pass
----------------
The University of Houston has licensed this new wire-making technology 
to MetOx, a company founded in 1997. MetOx plans to begin full-scale 
production of this high-quality HTS wire in 2003, Castellani says.

Not surprisingly, the primary scientist for the NASA group at TcSAM,
Dr. Alex Ignatiev, can't reveal exactly how they make their HTS wire.
The technologies springing from these NASA/industry research
partnerships must be patented to achieve NASA's goal of using space to 
benefit American businesses, Ignatiev says. 

He will, however, share the dinner-napkin sketch.

Basically, the wire is made by growing a thin film of the
superconductor only a few microns thick (thousandths of a millimeter)
onto a flexible foundation. This well-known production method was
improved upon in part through "Wake Shield" experiments flown on the
space shuttle to learn about growing thin films in the hard vacuum of
space. 

"We learned how to grow higher-quality oxide thin films from the
shuttle experiments, and used that in the lab to improve the quality
of our superconducting films," Ignatiev says. 

In the years to come, that quality will translate into improvements in 
dozens of industries from power generation to medical care. Keep an 
eye on this one: the glamorous career of superconductors has only just 
begun. 

Credits & Contacts
Author: Patrick L. Barry 
Responsible NASA official: Ron Koczor 
Production Editor: Dr. Tony Phillips 
Curator: Bryan Walls 
Media Relations: Steve Roy

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