Spectrolab's new solar cells have 28% efficiency
Production of this fourth-generation, radiation-hard triple-junction solar cell will begin in June 2003.
The UTJ cell builds on the extensive heritage of predecessor multi-junction GaAs/Ge solar cells: the Improved Triple-Junction or ITJ (with 37 kW operating in orbit), the Triple Junction or TJ (with 25 kW in orbit) and the Dual Junction or DJ (with 259 kW in orbit).
As solar cell efficiency rises, more of the sunlight spectrum is converted to electrical power, resulting in greater satellite payload capability or - for equivalent power output capability - smaller, lighter solar arrays.
"This is the highest performance space solar cell available anywhere in the world" said David Lillington, president of Spectrolab. "We are offering maximum flexibility to our customers by providing this state-of-the-art product at all levels of integration, from solar cell structures grown on epiwafers to fully-tested solar panels.
"Because the UTJ cell is an evolutionary improvement over our existing ITJ technology, we are immediately able to provide these products in very high volume, and at an affordable price, resulting in minimal technical and schedule risks for our customers."
In addition to improved power at beginning-of-life, the UTJ cell retains more it its initial performance with an end-of-satellite-life efficiency of 25.2 percent after 15 years* operation in geosynchronous orbit. (*After 15 years, the assumed radiation fluence is 5x1014 1 MeV electrons/cm2 and 28 degrees C.)
The UTJ cell also incorporates several improvements in the assembled configuration, including all-welded interconnection, monolithic bypass diode compatibility, and reduction in mass.
Spectrolab has been producing solar cells for the space industry since 1958 and since 1995 has boosted space solar cell efficiencies from 19 percent to 28 percent. It has also increased its solar cell production capacity to deliver nearly 1 megawatt of power per year (the equivalent of 60 typical 16 kW satellites) to global spacecraft manufacturers.
Spectrolab was the first company to introduce dual-junction and then triple-junction solar cells to the commercial marketplace. To date Spectrolab has delivered more than 1,500,000 multi-junction GaAs/Ge solar cells to flight programs - enough to generate more than 800 kilowatts of power combined.
