Boeing Spectrolab reaches an industry milestone for solar cells

Boeing Spectrolab Inc., the world’s largest manufacturer of space solar cells, has reached an unprecedented industry milestone by producing more than one million multijunction gallium arsenide solar cells.

“I am proud of our team’s accomplishment in delivering over one million advanced solar cells and the quarter-megawatt of power they provide to operating spacecraft using this technology,” said David Lillington, president of Spectrolab. “This is a direct reflection of our ability to continuously improve our technology and provide our customers with high-quality, competitive power system design choices.”

The million multijunction solar cells produced by Spectrolab are a combination of dual-junction, triple-junction, and improved triple-junction solar cells. “Multijunction” refers to a layered structure that captures solar energy and converts it into electricity. Each junction converts a different portion of the solar spectrum. Increasing the number of junctions tends to improve a solar cell’s ability to convert light into electricity.

The dual-junction solar cell, first produced in 1997, provides a beginning-of-life efficiency—the amount of sunlight converted into energy—of 21.5 percent. In November 2001, triple-junction solar cells made their inaugural commercial satellite flight on DIRECTV-4S, providing a beginning-of-life efficiency of 24.5 percent.

Improved triple-junction solar cells first flew on Galaxy IIIC in June. This model already represents over 20 percent of the multijunction cells produced to date and boasts a beginning-of-life conversion efficiency of over 26.5 percent.

“This volume of solar cells provides our satellite customers with a solid inflight record of performance backed by years of on-orbit operation,” Lillington said. “Our objective continues to be to make timely, evolutionary improvements to our solar designs, thereby building on our very extensive flight heritage.”

Production of the next-generation Spectrolab solar cell, the ultra-triple-junction solar cell, will begin in the fourth quarter of this year. The solar cell will achieve over 28 percent conversion efficiency. Spectrolab is developing cells capable of more than 30 percent efficiency and expects to begin manufacturing them around 2004.

Spectrolab has produced solar cells for the space industry since 1958. Its customers include most of the world’s prime spacecraft and solar array manufacturers.