The digital data were displayed on a standard TV monitor, where engineers observed moving images of a human hand and simulated spacecraft.

"This demonstration marks an important step toward better and cheaper satellite-based infrared imaging for commercial, space science and military missions," said Larry Eaton, TRW's superconducting electronics program manager.

"The improved imaging capability will help sensors track and image very faint or very cool objects in space, such as distant stars or incoming ballistic missiles in their midcourse phase.

"Superconducting circuits greatly boost the speed of imaging systems, which operate at temperatures near absolute zero (10 degrees Kelvin or -273 degrees Celsius), while dramatically cutting overall size, complexity, power consumption and cost -- all key advantages for any satellite."

At the heart of the breakthrough is a tiny, TRW-developed superconducting chip that performs high-speed digital signal processing like a conventional silicon integrated circuit, but consumes 1,000 times less electrical power. The superconductor chip is also hundreds of times smaller and lighter.

Superconductivity is a phenomenon exhibited by certain materials in which all resistance to electrical current disappears when the material is cooled to a very low temperature. In theory, a current introduced under superconducting conditions will flow forever without experiencing any electrical losses.

Funded jointly by the Ballistic Missile Defense Organization and NASA, the imaging system was integrated by TRW and NASA at JPL's facilities in Pasadena, Calif. It includes the TRW-built superconducting analog-to-digital converter (ADC) chip coupled to the sensor, a Boeing-supplied focal plane array cooled to about 10 degrees above absolute zero.

No-Heat Chip Allows Integration With Focal Plane Array

The project represents the first time that a superconducting chip has been integrated with a focal plane array. "TRW's ADC circuit itself uses less than 40 microwatts, while the full chip consumes barely one-third of a milliwatt -- about 1,000 times less power than a comparable silicon circuit -- hence, it generates almost no heat," Eaton said.

"As a result, we were able to put the chip in the same compartment as the infrared sensors, which must be kept at about 10 degrees above absolute zero." The test bed illustrates graphically how the insertion of small, low-power superconducting electronics can simplify the design and construction of focal plane array systems, Eaton added.

Placing the ADC chip next to the focal plane sensor leads to major improvements in the performance of space-based imaging systems. "By converting the incoming signals to digital form at the focal plane, we eliminated the noise-susceptible analog transmission lines previously needed to carry the signals away from the focal plane," Eaton said.

"The removal of this potential noise source helps preserve the quality of the original signal, which will allow us to produce images of fainter objects at greater distances."

TRW's ADC chip, whose key electronic elements are made from niobium nitride, was designed, fabricated and tested at the company's superconducting electronics foundry in Redondo Beach, the only facility of its kind in the world. In production quantities, the chip is expected to operate 10 times faster and consume about 1,000 times less power than a comparable silicon-based ADC chip.