2 images. Solar cells and vanguard, 18 March 1958. I.J. Kaar (Vice President and Engineering Director of Hoffman Electronics Corporation).; Caption slip reads: "Photographer: Wyman. Date: 1958-03-18. Reporter: Donoghue. Assignment: Solar cells and vanguard. Special instructions: Daily. 41/45: I.J. Kaar, vice president and engineering director of Hoffman Electronics Corporation, with exact scale model of Vanguard satellite, as he explains how solar (sun power) converters are used to generate electric impulses for the satellite's radio. Kaar holds solar disk crystal of silicon from which disk was sliced".