S  K  Y  L  A  B
Skylab used traditional silicon based solar panels

Silicon based space solar cells have a maximum theoretical efficiency around 23%
In 1958, the U.S. Vanguard space satellite carried a small array of PV cells to power its radio. The cells worked so well that PV technology has been part of the space progaram ever since. Today, solar cells power virtually all satellites, including those used for communications, defense, and scientific research.