Louise Shepard, wife of the pioneering Mercury astronaut Alan Shepard, died while traveling just a month after her husband's death, NASA officials said.
Friends said Louise Shepard suffered a heart attack Tuesday on a flight from San Francisco to her home in Monterey. She was believed to have been 74.She died while returning from a visit with a daughter in Colorado, friends said.
Her husband, one of the original seven astronauts on the United States' pioneering Freedom 7 Mercury voyage into space in 1961, died in his sleep last month at age 74 while being treated for leukemia.