 He pursued his postdoctoral work at New York University.Working from NASA's Langley Research Center in the mid- to late-1970s, Dr. Soffen was project scientist for the NASA's Viking program of Mars landers, the first successful missions to perform unmanned experiments on the surface of the planet.In that role, he oversaw all scientific investigations conducted by the landers, coordinating the work of more than seventy scientists around the nation.